tag:theconversation.com,2011:/au/topics/convergent-evolution-10224/articlesConvergent evolution – The Conversation2024-01-14T19:05:59Ztag:theconversation.com,2011:article/2195772024-01-14T19:05:59Z2024-01-14T19:05:59ZDo they see what we see? Bees and wasps join humans in being tricked by illusions of quantity<figure><img src="https://images.theconversation.com/files/565690/original/file-20231214-18-xu49z8.jpg?ixlib=rb-1.1.0&rect=404%2C0%2C2068%2C1213&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Scarlett Howard</span></span></figcaption></figure><p>If you’ve ever been tricked by a visual illusion, you know the feeling of disconnect between what your eyes perceive and what is actually there. Visual illusions occur due to errors in our perception, causing us to misperceive certain characteristics of objects or scenes.</p>
<p>As it turns out, many non-human animals also experience these effects, including illusions of item size, brightness, colour, shape, orientation, motion or quantity. We study these illusions and the differences between animals as it can tell us how visual systems evolved.</p>
<p>Our latest study, published in <a href="https://www.cell.com/iscience/fulltext/S2589-0042(23)02774-8">iScience</a>, shows that European honeybees and European wasps see illusions of quantity in a similar way to humans.</p>
<figure class="align-center ">
<img alt="Muller-Lyer illusion; Vertical-horizontal illusion; Ponzo illusion; Illusory contour; Delboeuf illusion; Ebbinghaus illusion" src="https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568540/original/file-20240110-21-nn3vhp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Examples of different visual illusions where the eye is tricked to perceive incorrect proportions of objects.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<h2>An illusion perceived by several species</h2>
<p>The study of visual illusions provides interesting windows into how brains operate. Visual illusions are perceptual errors, which likely enable us to process complex natural information efficiently.</p>
<p>The Solitaire illusion causes a misperception of quantity based on the configuration of dots in an image. Those who perceive the illusion will overestimate the quantity of dots when they are clustered together and/or underestimate the number of dots when unclustered.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two images containing a cross shape made up of yellow and blue dots" src="https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=313&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=313&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=313&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=393&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=393&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565938/original/file-20231215-20-ftnpzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=393&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An example of the Solitaire illusion. The yellow elements generally appear more numerous on the right than the left, despite both images having an identical quantity of yellow and blue elements.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<p>We know the Solitaire illusion is perceived by <a href="https://psycnet.apa.org/record/2014-33482-001">humans, capuchin monkeys</a>, <a href="https://psycnet.apa.org/record/2017-55920-001">guppies</a> and <a href="https://www.biorxiv.org/content/10.1101/2023.08.22.554303v1.abstract">bumblebees</a>. <a href="https://psycnet.apa.org/record/2014-33482-001">Chimpanzees, rhesus monkeys</a> and <a href="https://www.mdpi.com/2076-2615/10/12/2304">domestic dogs</a> do not appear to perceive the illusion. Interestingly, in humans age appears to impact the perception of the Solitaire illusion – younger children are less susceptible than <a href="https://www.sciencedirect.com/science/article/pii/S0022096515002258">older children</a>.</p>
<p>A possible evolutionary reason humans and other species may experience this misperception of quantities is it may allow us to process and compare large numbers of items more efficiently and quickly.</p>
<p>For quantities greater than about five, fast decisions may be more important than absolute accuracy, which would require manual, sequential counting.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/one-then-some-how-to-count-like-a-bee-138815">One, then some: how to count like a bee</a>
</strong>
</em>
</p>
<hr>
<h2>Testing honeybees</h2>
<p>Some insects, including bees and wasps, are very “motivated” to participate in behavioural experiments. European honeybees and wasps are central-place foragers: they will return to the location of a high-quality food source.</p>
<p>We provided freely flying bees and wasps with a reward of sugar water for participating in experiments. This allows us to train and test individually colour-marked insects throughout a day, with them returning by their own choice.</p>
<p>We have used this method to show honeybees can perform a variety of numerical tasks such as <a href="https://theconversation.com/bees-join-an-elite-group-of-species-that-understands-the-concept-of-zero-as-a-number-97316">understanding the concept of zero</a>, <a href="https://theconversation.com/bees-can-learn-higher-numbers-than-we-thought-if-we-train-them-the-right-way-124887">discriminating between quantities</a>, <a href="https://theconversation.com/can-bees-do-maths-yes-new-research-shows-they-can-add-and-subtract-108074">performing simple addition and subtraction</a>, <a href="https://theconversation.com/we-taught-bees-a-simple-number-language-and-they-got-it-117816">matching symbols with quantities</a>, and <a href="https://theconversation.com/honeybees-join-humans-as-the-only-known-animals-that-can-tell-the-difference-between-odd-and-even-numbers-181040">categorising quantities as odd or even</a>.</p>
<p>Honeybees are also known to perceive some <a href="https://theconversation.com/which-square-is-bigger-honeybees-see-visual-illusions-like-humans-do-87673">spatial</a>, movement and colour illusions. These past skills make them an ideal candidate to study and see if they are fooled by illusions of quantity.</p>
<p>Wasps are far less tested than honeybees for their behaviour and cognition, but recent <a href="https://theconversation.com/many-people-hate-wasps-but-theyre-smarter-than-you-might-think-and-ecologically-important-212706">studies</a> show they are also capable of advanced learning. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A grey circular screen displaying stimuli to insects" src="https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=706&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=706&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=706&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=888&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=888&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565683/original/file-20231214-29-eewqnt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=888&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The circular rotating screen used to present stimuli to insects during training and testing. Insects were trained one at a time and rewarded with a sugar water drop for landing on the correct stimulus option during training.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<h2>Bees, wasps and the Solitaire illusion</h2>
<p>We tested the European honeybee (<em>Apis mellifera</em>) and the European wasp (<em>Vespula vulgaris</em>) using an identical method for both species.</p>
<p>We presented each insect with images containing blue and yellow dots. For 70 trials, the insects were trained with a sugar reward to visit an image with a higher quantity of yellow dots versus blue.</p>
<p>We then presented them with the Solitaire illusion – one image with the yellow dots clustered in the middle and the blue dots unclustered, versus one image of the opposite. </p>
<p>The images actually contained an identical number of blue and yellow dots. So, if the insects perceived the illusion, they would choose the option with the yellow dots clustered in the centre, revealing an overestimation of the quantity of yellow dots.</p>
<p>We found both honeybees and wasps perceived the illusion in a similar way to humans, capuchin monkeys and guppies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A wasp sits on a platform in front of an image of yellow and blue dots. A honeybee is approaching to land" src="https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565942/original/file-20231215-15-307y5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A bee and wasp in front of one of the training images.</span>
<span class="attribution"><span class="source">Scarlett Howard</span></span>
</figcaption>
</figure>
<h2>Is there an evolutionary clue here?</h2>
<p>We now know the perception of the Solitaire illusion occurs across a range of species including humans, non-human primates, fish and insects. There are also primates and other mammals that appear not to perceive the illusion.</p>
<p>This could suggest two potential evolutionary pathways of experiencing the illusion. </p>
<p>One is <em>convergent</em> evolution, where different species separately developed the ability to perceive this illusion due to the requirements of their environment.</p>
<p>The other pathway is that the perception occurred through <em>conserved</em> evolution, where a common ancestor perceived the illusion, and subsequently some species either retained or lost the illusion perception.</p>
<p>One important consideration is that while the Solitaire illusion is considered an illusion of quantity, it could also be perceived as an illusion of colour area, size, line length, or perimeter. More research will be needed to determine whether the illusion induces the misperception of quantity or other cues that correlate with quantity.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/which-square-is-bigger-honeybees-see-visual-illusions-like-humans-do-87673">Which square is bigger? Honeybees see visual illusions like humans do</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/219577/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scarlett Howard receives funding from the Australian Research Council, Monash University, Australian Academy of Sciences, and the Hermon Slade Foundation. She is affiliated with Triple R.</span></em></p><p class="fine-print"><em><span>Adrian Dyer receives funding from the Alexander von Humboldt Foundation, the Air Force Office of Scientific Research and the Australian Research Council.</span></em></p>Being susceptible to visual illusions is part and parcel of life not just for humans, but many other species – including bees.Scarlett Howard, Lecturer, School of Biological Sciences, Monash UniversityAdrian Dyer, Associate Professor, Department of Physiology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2021522023-03-24T19:20:10Z2023-03-24T19:20:10ZMarsupials and other mammals separately evolved flight many times, and we are finally learning how<figure><img src="https://images.theconversation.com/files/516876/original/file-20230322-174-mlvqar.jpg?ixlib=rb-1.1.0&rect=1818%2C745%2C3145%2C2031&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Anom Harya/Shutterstock</span></span></figcaption></figure><p><a href="https://www.goodreads.com/quotes/4324-shoot-for-the-moon-even-if-you-miss-you-ll-land">Shoot for the moon</a>. Even if you miss, you’ll land on the next tree. Many groups of mammals seem to have taken this evolutionary advice to heart. According to our <a href="http://dx.doi.org/10.1126/sciadv.ade7511">newly published paper in Science Advances</a>, unrelated animals may even have used the same blueprints for building their “wings”.</p>
<p>While birds are the undisputed champions of the sky, <a href="https://doi.org/10.1016/j.cub.2015.08.003">having mastered flight during the Jurassic</a>, mammals have actually evolved flight more often than birds. In fact, as many as seven different groups of mammals living today have <a href="https://doi.org/10.1111/evo.14094">taken to the air independently of each other</a>.</p>
<p>These evolutionary experiments happened in animals scattered all across the mammalian family tree – including flying squirrels, marsupial possums and the colugo (cousin of the primates). But they all have something in common. It’s a special skin structure between their limbs called a patagium, or flight membrane. </p>
<p>The fact these similar structures have arisen so many times (a process called <a href="https://doi.org/10.1098/rstb.2019.0102">convergent evolution</a>) hints that the genetic underpinnings of patagia might predate flight. Indeed, they could be shared by all mammals, even those living on the ground. </p>
<p>If this is true, studying patagia can help us to better understand the incredible adaptability of mammals. We might also discover previously unknown aspects of human genetics.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A cute grey and cream striped animal on a tree branch with distinctive skin folds visible on its side" src="https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=498&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=498&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=498&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=626&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=626&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516879/original/file-20230322-18-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=626&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sugar gliders are one of several mammals that have independently evolved the ability to fly through the air.</span>
<span class="attribution"><span class="source">apiguide/Shutterstock</span></span>
</figcaption>
</figure>
<h2>A deceptively simple membrane</h2>
<p>Despite being seemingly simple skin structures, patagia contain several tissues, including hair, a rich array of <a href="https://doi.org/10.1073/pnas.1018740108">touch-sensitive neurons</a>, <a href="https://doi.org/10.1071/ZO9870101"></a><a href="https://doi.org/10.1038/ncomms2298">connective tissue and even thin sheets of muscle</a>. But in the earliest stages of formation, these membranes are dominated by the two main layers of the skin: the inner dermis and outer epidermis.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A pink baby animal looking much like an embryo with a red arrow pointing at a thin membrane it its armpit" src="https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=780&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=780&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=780&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=980&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=980&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516542/original/file-20230321-22-8mhzbz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=980&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The patagium in sugar gliders (red arrow) forms after birth when the newborn, or joey, is in its marsupial mother’s pouch.</span>
<span class="attribution"><span class="source">Charles Feigin</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>At first, they hardly differ from neighbouring skin. But at some point, the skin on the animal’s sides starts to rapidly change, or differentiate. The dermis undergoes a process called condensation, where cells bunch up and the tissue becomes very dense. Meanwhile, the epidermis thickens in a process called hyperplasia.</p>
<p>In some mammals, this differentiation happens when they are still an embryo in the uterus. Incredibly though, in our main model species – the marsupial sugar glider (<em><a href="https://australian.museum/learn/animals/mammals/sugar-glider/">Petaurus breviceps</a></em>) – this process begins after birth, while they are in the mother’s pouch. This provides us with an incredible window into patagium formation.</p>
<p>Starting with the sugar glider, we examined the behaviours of thousands of genes active during the early development of the patagium, to try and figure out how this chain of events is kicked off.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-rare-discovery-we-found-the-sugar-glider-is-actually-three-species-but-one-is-disappearing-fast-142807">A rare discovery: we found the sugar glider is actually three species, but one is disappearing fast</a>
</strong>
</em>
</p>
<hr>
<h2>From gliders to bats</h2>
<p>We discovered that levels of a gene called Wnt5a are strongly correlated with the onset of those early skin changes – condensation and hyperplasia. Through a series of experiments involving cultured skin tissues and genetically engineered laboratory mice, we showed that adding extra Wnt5a was all it took to drive both of these early hallmarks of patagium formation.</p>
<p>Interestingly, when we extended our work to bats, we found extremely similar patterns of Wnt5a activity in their developing lateral patagia to that in sugar gliders. This was surprising, since bats (placental mammals) last shared a common ancestor with the marsupial sugar glider around 160 million years ago.</p>
<p>Perhaps even more remarkably, we found a nearly identical pattern in the outer ear (or pinna) of lab mice. The pinna is a nearly universal trait among mammals, including innumerable species with no flying ancestry. </p>
<figure class="align-right ">
<img alt="A dark bat with an upturned nose with its wings spread out" src="https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=527&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=527&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=527&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=663&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=663&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516878/original/file-20230322-22-kkqk3x.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=663&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Seba’s short-tailed bat has a lateral patagium (connected to the flank of the body) activated by Wnt5a.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/110870566">Irineu Cunha/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>A molecular toolkit</h2>
<p>Together, these results suggest something profound. Wnt5a’s role in ushering in the skin changes needed for a patagium likely evolved long before the first mammal ever took to the air.</p>
<p>Originally, the gene had nothing to do with flight, instead contributing to the development of seemingly unrelated traits. But because of shared ancestry, most living mammals today inherited this Wnt5a-driven program. When species like gliders and bats started on their separate journeys into the air, they did so with a common “molecular toolkit”.</p>
<p>Not only that, but this same toolkit is likely present in humans and working in ways we don’t fully understand yet.</p>
<p>There are definite limits to our recent work. First, we haven’t made a flying mouse. This may sound like a joke, but demonstrates we still don’t fully understand how a region of dense, thick skin becomes a thin and wide flight membrane. Many more genes with unknown roles are bound to be involved.</p>
<p>Second, while we’ve shown a cause-and-effect relationship between Wnt5a and patagium skin differentiation, we don’t know precisely how Wnt5a does it. Moving forward, we hope to fill in these gaps by broadening the horizons of our cross-species comparisons and by conducting more in-depth molecular studies on patagium formation in sugar gliders.</p>
<p>For now though, our study presents an exciting new view of flight in mammals. We may not be the strongest fliers, but trying is in our DNA.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mysterious-poles-make-road-crossing-easier-for-high-flying-mammals-11323">Mysterious poles make road crossing easier for high flying mammals</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/202152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charles Feigin has received fellowship funding from the National Institutes of Health National Institute of General Medical Sciences </span></em></p>Mammals have evolved flight more often than birds. By studying the genes of the sugar glider, biologists have found a ‘molecular toolkit’ for flight membranes that’s been in us all along.Charles Feigin, Postdoctoral Fellow in Genomics and Evolution, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1691272021-10-18T12:11:42Z2021-10-18T12:11:42ZHow to nurture creativity in your kids<figure><img src="https://images.theconversation.com/files/426475/original/file-20211014-7324-1u31syx.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4998%2C3344&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Creativity has many academic, professional and personal benefits.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/four-children-drawing-with-chalk-on-pavement-royalty-free-image/AB15713">Stephen Simpson/Stone Collection via Getty Images</a></span></figcaption></figure><p>Parents who want their kids to be more creative may be tempted to enroll them in arts classes or splurge on STEM-themed toys. Those things certainly can help, but as a <a href="https://scholar.google.com/citations?user=OzW_dWUAAAAJ&hl=en&oi=ao">professor of educational psychology</a> who has <a href="https://doi.org/10.1017/9781316979839">written</a> <a href="https://www.springerpub.com/creativity-101-9780826129529.html">extensively</a> <a href="https://doi.org/10.1037/a0013688">about creativity</a>, I can draw on more than <a href="https://doi.org/10.1037/h0063487">70 years of creativity research</a> to make additional suggestions that are more likely to be effective – and won’t break your budget. </p>
<h2>1. Be cautious with rewards</h2>
<p>Some parents may be tempted to reward their children for being creative, which is traditionally defined as producing something that is <a href="https://doi.org/10.1207/s15326985ep3902_1">both new and useful</a>. However, rewards and praise may actually <a href="https://doi.org/10.1037/0022-3514.50.1.14">dissuade your child’s intrinsic interest</a> in being creative. That’s because the activity may become <a href="https://www.springer.com/gp/book/9780306420221">associated with the reward and not the fun</a> the child naturally has doing it. </p>
<p>Of course, I am not saying you should not place your child’s artwork on your fridge. But avoid being too general – “I love every bit of it!” – or too focused on their innate traits – “You are so creative!” Instead, <a href="https://doi.org/10.1017/9781316832134.028">praise specific aspects</a> that you like in your child’s artwork – “I love the way you made such a cute tail on that dog!” or “The way you combined colors here is pretty!” </p>
<p>Some rewards can be helpful. For example, for a child who loves to draw, giving them materials that they might use in their artwork is an example of a reward that will <a href="https://doi.org/10.1017/9781316979839.020">help them stay creative</a>. </p>
<p>It is also important to note that there are many activities – creative or otherwise – for which a child may not have a particular interest. There is no harm – and much potential benefit – in using rewards in these cases. If a child has an assignment for a creative school activity and hates doing it, there may not be any inherent passion to be dampened in the first place.</p>
<figure class="align-center ">
<img alt="Boy draws at table partially covered with art supplies" src="https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/426576/original/file-20211014-7324-vetody.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">If a child already enjoys a creative activity, offering rewards or nonspecific praise for it may actually dampen their enthusiasm.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/young-boy-at-home-drawing-at-the-table-royalty-free-image/1257515701">Noel Hendrickson/DigitalVision Collection via Getty Images</a></span>
</figcaption>
</figure>
<h2>2. Encourage curiosity and new experiences</h2>
<p>Research shows that people who are <a href="https://doi.org/10.1017/9781316228036">open to new experiences and ideas</a> are more creative than those who are more closed off. Many parents have children who naturally <a href="https://doi.org/10.1016/j.jrp.2014.07.004">seek new things</a>, such as food, activities, games or playmates. In these cases, simply continue to offer opportunities and encouragement. </p>
<p>For those whose children may be more reticent, there are options. Although personality is theoretically stable, it is <a href="https://doi.org/10.1111/1467-6494.694157">possible to change</a> it <a href="https://doi.org/10.1037/bul0000088">in subtle ways</a>. For example, a study – although it was on older adults – found that <a href="https://doi.org/10.1037/a0025918">crossword or sudoku puzzles</a> can help increase openness. Childhood and adolescence is a <a href="https://doi.org/10.1037/0033-2909.132.1.1">natural period for openness to grow</a>. Encouraging curiosity and intellectual engagement is one way. Other ways might include encouraging sensible risk-taking – such as trying a new sport for a less athletic child or a new instrument for one less musically inclined – or <a href="https://doi.org/10.1177/0022022110361707">interest in other cultures</a>. Even very simple variations on an evening routine, whether trying a new craft or board game or helping cook dinner, can help normalize novelty. </p>
<h2>3. Help them evaluate their best ideas</h2>
<p>What about when children are actually being creative? Most people have heard of brainstorming or other activities where <a href="https://www.sciencedirect.com/topics/psychology/divergent-thinking">many different ideas are generated</a>. Yet it is equally important to be able to <a href="https://doi.org/10.1207/s15326934crj1803_13">evaluate and select one’s best idea</a>. </p>
<p>Your child might think of 30 possible solutions to a problem, but their creativity will not be expressed if they select the one that’s least interesting – or least actionable. If giving praise can be tricky, feedback can be even tougher. If you are too harsh, you risk <a href="https://www.doi.org/10.1037/a0036618">squashing your child’s passion</a> for being creative. Yet if you are too soft, your child may not develop their creativity <a href="https://doi.org/10.2190/EM.28.1.b">to the fullest extent possible</a>.</p>
<p>If your child seeks out your input – which in adults can be a <a href="https://doi.org/10.5465/amj.2011.64870144">good indicator of creativity</a> – make sure to give feedback <a href="https://doi.org/10.1080/10400410802391827">after they have already brainstormed</a> many possible ideas. Ideally, you can ensure your child still feels competent and focus on <a href="https://doi.org/10.3102/003465430298487">feedback that connects to their past efforts</a>: “I like the imagery you used in your poem; you are getting better! What other metaphors might you use in this last line?”</p>
<figure class="align-center ">
<img alt="Girl walks over an aerial bridge made of rope and planks surrounded by trees" src="https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/426574/original/file-20211014-28-ysbysf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">More guarded kids may need to be encouraged to try new foods or activities.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/girl-walks-through-one-of-the-circuits-of-the-aventura-news-photo/1335426205">Rafael Bastante/Europa Press via Getty Images</a></span>
</figcaption>
</figure>
<h2>4. Teach them when not to be creative</h2>
<p>Finally, <a href="https://doi.org/10.1080/02783193.2013.799413">creativity isn’t always the best option</a>. Sometimes, straightforward solutions simply work best. If the toilet is clogged and you have a plunger, you don’t need to make your own from a coat hanger and bisected rubber duck. </p>
<p>More notably, <a href="https://doi.org/10.1207/s15326934crj0801_1">some people</a>, <a href="https://doi.org/10.1002/j.2162-6057.2005.tb01247.x">including teachers</a>, say they like creative people but actually have negative views of creative kids without even realizing it. </p>
<p>If your child is in a class where their creativity is causing some blowback, such as discipline issues or lowered grades, you may want to work with your child to help them understand the best course of action. For example, if your child is prone to blurt out their ideas regardless of whether they are related to the discussion at hand, emphasize that they should <a href="https://doi.org/10.1080/13598139.2014.905247">share thoughts that are directly relevant</a> to the class topic. </p>
<p>If, however, you get the feeling that the teacher simply does not appreciate or like your child’s creativity, you may want to suggest that your child keep an “idea parking lot” where they <a href="https://brill.com/view/book/edcoll/9789462091498/BP000003.xml">write down their creative thoughts</a> and share them with you – or a different teacher – later in the day.</p>
<p>Creativity has a host of <a href="https://doi.org/10.1037/aca0000433">academic</a>, <a href="https://doi.org/10.1111/j.1744-6570.2001.tb00234.x">professional</a> and <a href="https://doi.org/10.1177/1745691618771981">personal</a> benefits. With some gentle nudges, you can help your child grow and use their imagination to their heart’s content.</p>
<p>[<em>Over 110,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/169127/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James C. Kaufman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Art classes and STEM toys are nice, but there are simple and free ways parents can encourage their child’s creativity – or keep it from getting squashed.James C. Kaufman, Professor of Educational Psychology, University of ConnecticutLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1599322021-05-13T02:27:32Z2021-05-13T02:27:32ZHow snake fangs evolved to perfectly fit their food<figure><img src="https://images.theconversation.com/files/399366/original/file-20210507-23-7ectsj.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4486%2C2991&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Mark Kostich / Shutterstock</span></span></figcaption></figure><p>Few structures in nature inspire more fear and fascination than the fangs of venomous snakes. </p>
<p>These needle-like teeth are used by snakes to pierce their prey and inject deadly venom. With more than 3000 species of snake inhabiting our world, we wondered: are all their fangs the same? Or are their fangs differently shaped depending on what they eat, as we find in other animal groups? </p>
<p>To uncover the answer, we examined the three-dimensional shape of snake fangs in 81 species and found that fangs have indeed evolved to suit the snake’s preferred prey, from hard-shelled crabs to furry mammals. Our results are published in the journal <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/evo.14239">Evolution</a>. </p>
<h2>Differences across snake families</h2>
<p>Venomous snakes are found all over the world and belong to five big families: vipers, atractaspidids, elapids, colubrids and homalopsids. Throughout evolution, each of these families independently “designed” their fangs and venom delivery systems, which led to slight differences.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Overview of the skulls across the different venomous snake families" src="https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=256&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=256&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=256&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397640/original/file-20210428-19-jvnlor.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Overview of the skulls across the five venomous snake families. Note the difference in the position of the fang inside the mouth, the size difference and the size of the (maxillary) bone the fang is attached to.</span>
<span class="attribution"><span class="source">Silke Cleuren</span></span>
</figcaption>
</figure>
<p>Vipers and atractaspidids have long tubular fangs that flip out when they strike, elapid snakes have short tubular fangs that are fixed to the jaw, and colubrids and homalopsids have grooved fangs all the way at the back of their mouths.</p>
<h2>Teeth are adapted to diet across the animal kingdom</h2>
<p>Variations in tooth shape according to diet are common in the mammal kingdom. Carnivores often have bladed cheek teeth to tear flesh, and herbivores have ridged molars to grind down leaves, roots, and other plant matter. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-teeth-can-tell-about-the-lives-and-environments-of-ancient-humans-and-neanderthals-104923">What teeth can tell about the lives and environments of ancient humans and Neanderthals</a>
</strong>
</em>
</p>
<hr>
<p>Venomous snakes vary in the types of prey they target. Some specialise in small mammals such as mice, some go for fish, shrimps or crabs, and some hunt reptiles and even other snakes. There are also generalists, which almost anything they can fit in their mouths. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Variation of tooth shapes across the animal kingdom" src="https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397649/original/file-20210428-23-ftwsgb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Variation of tooth shapes across the animal kingdom. This illustration shows that depending on the food you eat different optimal tooth shapes have evolved that are good at coping with the preferred food source of the animal.</span>
<span class="attribution"><span class="source">Silke Cleuren</span></span>
</figcaption>
</figure>
<h2>Linking fang shape to diet</h2>
<p>We examined the three-dimensional shape of fangs from 81 snake species belonging to four families, with the exception of the rare atractaspidids. By measuring differences in the strength and sharpness of the fangs, we were able to show how fang shape is closely tied to prey preference.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph showing variation in fang robustness and tip sharpness across snake diets" src="https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397586/original/file-20210428-21-1i9ltnm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Variation in fang tip sharpness (x-axis) and robustness (y-axis) for each of the different diet categories found in snakes. The fang shapes found in snakes with a specific diet are represented by the coloured lines.</span>
<span class="attribution"><span class="source">Silke Cleuren</span></span>
</figcaption>
</figure>
<p>Fangs are more robust and blunt in species that target tougher prey, such as lizards and crabs, and more slender and sharp-tipped in species that target prey with softer skins, such as mice. Additionally, we found fang shape demonstrated “<a href="https://theconversation.com/like-a-jackal-in-wolfs-clothing-the-tasmanian-tiger-was-no-wolfish-predator-it-hunted-small-prey-159343">evolutionary convergence</a>”: the fangs of distantly related species with the same diet are more similar than those of closely related species with different diets.</p>
<h2>Predicting the diet of rare and fossil snakes</h2>
<p>Knowing more about the foods each type of snake likes can be valuable for the future success of both snakes and their prey. In Australia, most threatened snake species are affected by loss of habitat, which likely also results in the inability to catch their preferred prey. </p>
<p>By investigating their fangs we can now predict the group of prey it most likely prefers. If we were to relocate snakes, we could use this information to choose a suitable habitat that contains its favourite meal. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/like-a-jackal-in-wolfs-clothing-the-tasmanian-tiger-was-no-wolfish-predator-it-hunted-small-prey-159343">Like a jackal in wolf’s clothing: the Tasmanian tiger was no wolfish predator — it hunted small prey</a>
</strong>
</em>
</p>
<hr>
<p>This knowledge can also be used in the other direction, for the conservation of threatened prey species, by protecting them against snakes that are a threat to them. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=442&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=442&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=442&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=555&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=555&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397632/original/file-20210428-15-16cpwjw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=555&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Silke Cleuren</span></span>
</figcaption>
</figure>
<p>Investigating the fangs from fossils of ancient snakes can shed light on which prey they likely targeted and how their habitat might have looked. Knowing the fang shapes of fossil snakes can help explain the wide variation in fangs we see today and how this variation ensured the continued success of some of nature’s most specialised predators.</p>
<h2>Can we use this to improve protective clothing?</h2>
<p>Given the threat snakes can pose to humans, understanding how fang shape varies can also help us to design better protective clothing. By testing how easily different fangs penetrate fabrics and other materials, we can make better choices of materials that actually protect against snake bites. </p>
<p>This could result in the improvement of clothing like hiking pants or shoes that will keep us safe if we accidentally get too close to a grumpy snake while trekking through their habitat. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=261&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=261&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=261&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=328&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=328&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397634/original/file-20210428-13-xs3x1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=328&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Protective clothing - snake gaiters.</span>
<span class="attribution"><span class="source">Snakeprotex</span></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/159932/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Silke GC Cleuren receives funding from the Monash Graduate Scholarship (MGS)
and the Monash International Tuition Scholarship for her doctoral studies. The research was also funded by the Holsworth
Wildlife Research Endowment – Equity Trustees Charitable Foundation & the Ecological Society of
Australia.</span></em></p><p class="fine-print"><em><span>Alistair Evans receives funding from the Australian Research Council and Monash University, and is an Honorary Research Affiliate with Museums Victoria.</span></em></p><p class="fine-print"><em><span>David Hocking does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Some snakes have tough, blunt fangs for cracking crabs. Others have sharp needles for getting a grip on mice.Silke Cleuren, PhD candidate, Monash UniversityAlistair Evans, Associate Professor, Monash UniversityDavid Hocking, Curator of Vertebrate Zoology and Palaeontology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1593432021-04-22T04:30:39Z2021-04-22T04:30:39ZLike a jackal in wolf’s clothing: the Tasmanian tiger was no wolfish predator — it hunted small prey<figure><img src="https://images.theconversation.com/files/396409/original/file-20210421-17-sohn8m.png?ixlib=rb-1.1.0&rect=81%2C0%2C1441%2C773&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>The thylacine (<em>Thylacinus cynocephalus</em>), commonly known as the Tasmanian tiger, is an Aussie icon. It was the largest historical marsupial predator and a powerful example of human-caused extinction. And despite being extinct <a href="https://www.nma.gov.au/defining-moments/resources/extinction-of-thylacine">since 1936</a>, it still gets featured in <a href="https://www.nytimes.com/2021/03/10/science/thylacines-tasmanian-tigers-sightings.html">popular media</a>.</p>
<p>Yet much is still unknown about the thylacine, as its extinction left us with almost no direct observational data. Several mysteries remain regarding its specific ecology, including the question of how wolf-like it was. </p>
<p>In a new study published in <a href="https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-021-01788-8">BMC Ecology & Evolution</a>, my colleagues and I tackle this question. We show the thylacine was indeed similar to canids, a family which includes dogs, wolves and foxes. </p>
<p>But more specifically, it was similar to those canids which evolved to hunt small animals — as opposed to the wolf (<em>Canis lupus</em>) or wild dog/dingo (<em>Canis lupus dingo</em>), which are large-prey specialists. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-tasmanian-tiger-was-hunted-to-extinction-as-a-large-predator-but-it-was-only-half-as-heavy-as-we-thought-144599">The Tasmanian tiger was hunted to extinction as a 'large predator' – but it was only half as heavy as we thought</a>
</strong>
</em>
</p>
<hr>
<h2>Moulded by our environments</h2>
<p>When European colonisers first saw the thylacine, they noted its wolf-like appearance and judged it based on that assumption: like the wolf, it would pose a threat to their livestock.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395987/original/file-20210420-17-4hmty5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The thylacine and its canid comparatives.</span>
<span class="attribution"><span class="source">Thylacine photo by E.J.K. Baker and colourised by D.S. Rovinsky; wolf photo by Neil Herbert; dingo photo by Jarrod Amoore.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This superficially wolf-like appearance has been taken to mean the thylacine is a textbook example of convergent evolution: where two unrelated animals evolve similar traits in response to similar pressures. The similarities are so striking it’s even sometimes called the “marsupial wolf”.</p>
<figure class="align-center ">
<img alt="Swordfish, extinct dolphin and ichthyosaur." src="https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395989/original/file-20210420-23-6oajrw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Although <em>Eurhinosaurus</em> (bottom) is a reptile and <em>Eurhinodelphis</em> (middle) is a mammal, both are strikingly convergent with the modern swordfish. Thus, we can infer a great deal about their ecology.</span>
<span class="attribution"><span class="source">D.S. Rovinsky</span></span>
</figcaption>
</figure>
<p>Studying convergent evolution is a promising way for scientists to infer the behaviour and ecology of extinct animals that can’t be directly observed. Ecology is the study of how species interact with their physical surroundings. So, if an extinct animal shares a similar shape with one living today, we can assume they probably filled a similar ecological niche.</p>
<p>Since the thylacine’s ecology is uncertain, comparisons with comparable species are one of the only ways to understand it. And it’s wolf-like appearance at face value has led to the thylacine and its ecology being assumed similar to that of the grey wolf and its closest relatives, such as the dingo.</p>
<p>But what if that was wrong?</p>
<h2>Getting into the right headspace</h2>
<p>We decided to put this assumption of ecological similarity to the test. To do so we needed a wide range of ecologically meaningful animals to compare with the thylacine. After all, even though the thylacine was a marsupial (like a koala) it’s fair to say it wasn’t hanging out in trees munching on eucalyptus! </p>
<p>Using hand-held 3D scanners, we scanned hundreds of skulls from 56 different species of carnivorous mammals, with specimens obtained from more than a dozen museums around the world. This enabled us to build a skull “shapespace” to then see where the thylacine would fit among the others.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Evolutionary tree of comparative species" src="https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395990/original/file-20210420-15-4p63dz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A broad selection of ecologically-meaningful species, shown on this wheel-shaped evolutionary tree, were selected to compare to the thylacine.</span>
<span class="attribution"><span class="source">D.S. Rovinsky</span></span>
</figcaption>
</figure>
<p>We looked for evidence of convergent evolution by observing which of the other carnivorous mammals’ skulls were shaped most like the thylacine’s. </p>
<h2>A case of mistaken identity</h2>
<p>It turns out the skull shape of the thylacine is significantly convergent with that of some canids, but not with the usual suspects. We found no meaningful level of convergence with either the grey wolf or the dingo, and only a small degree with the red fox. </p>
<p>What we did find, however, was strong support for convergent evolution between the skulls of the thylacine and another rag-tag group of canids: African jackals and South American “foxes” (which aren’t actually foxes). Ecologically, these canids are vastly different from the wolf and dingo. Also, unlike the wolf, they specialise in hunting small prey.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Skulls showing difference between wolf, thylacine and small prey-hunting dogs" src="https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395994/original/file-20210420-15-934ote.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The wolf skull on the left is more different (shown by colour) to the thylacine skull than the skull in the middle, which is the average skull shape of the significantly convergent canids. White areas are more similar to the thylacine skull, while blue and red respectively show constriction or expansion. The difference is especially strong in the facial area, where the biting happens!</span>
<span class="attribution"><span class="source">D.S. Rovinsky</span></span>
</figcaption>
</figure>
<p>This brings us back to one of the more powerful uses of studying convergent evolution: the ability to infer the ecology of an extinct animal. Since the thylacine’s skull shape was more similar to that of the African jackals and South American “foxes” than the wolf, it likely shared a similar ecological niche with the former.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Group of delicate-faced dogs, looking like the thylacine." src="https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395995/original/file-20210420-23-uee4be.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The canids most like the thylacine are all small-prey hunters with relatively delicate faces — not robust big-biters like the wolf or dingo.</span>
<span class="attribution"><span class="source">D.S. Rovinsky</span></span>
</figcaption>
</figure>
<p>Therefore, the thylacine probably also <a href="https://theconversation.com/thylacine-misrepresented-no-jaws-for-alarm-3181">preferred hunting relatively small prey</a> such as pademelons, bettongs, bandicoots and young wallabies.</p>
<p>Interestingly, however, one of the most striking findings was that the thylacine did not actually overlap with any of the other predators, canid or otherwise. While it was <em>similar</em> to some canids, it was not identical. This highlights that even our more precise analysis may paint the thylacine with too broad a brush.</p>
<h2>Judged by appearance</h2>
<p>The thylacine was hunted to extinction for its wolf-like appearance. This reaction, like most based on first glance, was devastatingly wrong. Although the thylacine turns out to not be very wolf-like, it’s still a wonderful example of convergent evolution. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-did-the-tasmanian-tiger-go-extinct-11324">Why did the Tasmanian tiger go extinct?</a>
</strong>
</em>
</p>
<hr>
<p>Then again, it truly was different enough from other carnivorous mammals that we still can’t say we precisely understand its ecological niche. When we lost the thylacine, we lost something truly unique for its time. </p>
<p>Our understanding of the thylacine is, even now, that of a faded and blurry snapshot. Perhaps, with more research in the coming years, we can make it a little more clear.</p><img src="https://counter.theconversation.com/content/159343/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alistair Evans receives funding from the Australian Research Council and Monash University, and is an Honorary Research Affiliate with Museums Victoria.</span></em></p><p class="fine-print"><em><span>Justin W. Adams receives funding from the Australian Research Council and Monash University, and is an Honorary Research Affiliate with Museums Victoria.</span></em></p><p class="fine-print"><em><span>Douglass S Rovinsky does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Tasmanian tiger’s superficial appearance was so similar to a wolf’s that European colonisers assumed it was a threat and hunted it to extinction.Douglass S Rovinsky, Associate research scientist, Monash UniversityAlistair Evans, Associate Professor, Monash UniversityJustin W. Adams, Senior Lecturer, Department of Anatomy and Developmental Biology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1527202021-01-20T13:31:45Z2021-01-20T13:31:45ZStickiness is a weapon some plants use to fend off hungry insects<figure><img src="https://images.theconversation.com/files/377854/original/file-20210108-15-ukf9cf.JPG?ixlib=rb-1.1.0&rect=23%2C17%2C3858%2C2549&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A coat of sand makes an effective armor.</span> <span class="attribution"><span class="source">Eric LoPresti</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Imagine the texture of a plant. Many may come to mind – the smooth rubberiness of many tropical houseplants, the impossibly soft lamb’s ear, the sharp spines of cacti, or the roughness of tree bark. But stickiness, in the flypaper-stick-to-your-fingers sense, probably isn’t at the top of your list. </p>
<p>Nevertheless, a great many <a href="https://www.doi.org/10.1890/15-0342.1">plants have evolved sticky leaves</a>, stems and seeds, including some you likely know – such as petunias and tobacco. </p>
<p>In evolutionary biology, a trait that has evolved many times is interesting, since it suggests that over and over this trait serves some benefit. While people have noticed and discussed this odd characteristic for a great many years, <a href="https://scholar.google.com/citations?hl=en&user=7l5UAp4AAAAJ">biologists like me</a> are finally beginning to understand what stickiness is for – and why so many plants have it. </p>
<h2>Sand and stickiness</h2>
<p>Sticky plants are widespread. They are found in temperate and tropical areas, in wet and dry places and in forests, fields and dunes. In each of these environments, stickiness functions somewhat differently. </p>
<p>I am naturally drawn to sand dunes, whether in dry deserts or along beautiful coastlines, and stickiness has some interesting functions for plants in these locations. Shifting sand presents a challenging environment for plants – sand-blasting winds, potential burial and the lack of water retention are just a few.</p>
<p>Interestingly, hundreds of <a href="https://www.doi.org/10.1002/fedr.19961070510">plant species in sand dunes have evolved sticky surfaces</a>, suggesting utility in that habitat. Windblown sand coats these sticky surfaces – a phenomenon known as psammophory, which means “sand-carrying” in Greek. While a sandy coating may limit light from reaching plant surfaces, it also likely protects plants from abrasion and reflects light, reducing leaf temperature. It also defends plants from hungry predators.</p>
<p>A few years ago, my colleagues and I <a href="https://www.doi.org/10.1890/15-1696.1">studied yellow sand verbena (<em>Abronia latifolia</em>) plants in coastal California</a>. When we gently removed sand from leaves and stems, those leaves and stems got eaten by hungry snails, caterpillars and other herbivorous animals at twice the rate of sand-intact leaves and stems.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close up of plant leaves covered in green tinted sand." src="https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378083/original/file-20210111-23-my6dah.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Leaves covered in colored sand to test whether camouflage is a factor.</span>
<span class="attribution"><span class="source">Eric LoPresti</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We wondered if the sand might be protecting plants by camouflaging them. With a second experiment, we carefully cleaned and re-coated some verbena leaves with tinted sand that didn’t match the background. It turned out the color of the sand didn’t matter – <a href="https://www.doi.org/10.1890/15-1696.1">predators ate the sand-covered leaves at the same rate</a>, regardless of whether they blended with their background or not – showing sand protects plants as a physical barrier, rather than as a camouflage.</p>
<h2>Wearing down mouthparts</h2>
<p>This result makes intuitive sense – after all, who wants to eat something covered in sand, even if it is nutritious? Yet I’ve observed over the years that a great many herbivorous insects do indeed eat sandy leaves. It got me wondering what effect the sand might be having on them, so we did a series of simple experiments. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A microscopic view of two different sets of mandibles. One shows pointy 'teeth,' while the other looks worn down." src="https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=242&fit=crop&dpr=1 600w, https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=242&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=242&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=305&fit=crop&dpr=1 754w, https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=305&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/377857/original/file-20210108-23-1w4o9js.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=305&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The mandible of a caterpillar eating clean leaves (left), versus the worn-down mandible of one eating sand-encrusted leaves (right).</span>
<span class="attribution"><span class="source">Eric LoPresti</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>When we gave caterpillars a choice between eating sand-free and sand-covered plants, <a href="https://www.doi.org/10.1111/een.12483">they overwhelmingly chose to eat sand-free plants</a>. When we gave caterpillars no choice – one group getting only sandy leaves, the other getting clean leaves – we observed the mandibles, or mouthparts, of the sand eaters were noticeably worn down. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close up shot of a caterpillar's stomach contents, which show grains of sand amid digested leaves." src="https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378319/original/file-20210112-21-15ryy0c.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The gut contents of a caterpillar fed sand-coated leaves. Note the many grains of sand present.</span>
<span class="attribution"><span class="source">Eric LoPresti</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The sand-eating caterpillars also <a href="https://www.doi.org/10.1111/een.12483">grew about 10% more slowly</a> than those fed on nonsandy foliage, we suspect in part because they were ingesting some sand.</p>
<h2>Sticky seeds</h2>
<p>In sandy areas, it’s also common to find seeds that become sticky when moistened. Such seeds are coated in mucilage, which are simple carbohydrates that, in the presence of water, become a sticky mess. Even when they dry out, they can become sticky again, virtually indefinitely. You may be familiar with this phenomenon in chia seeds – mucilage is what gives chia pudding its distinctive texture. </p>
<p>When a mucilage-coated seed falls into sand, gets moistened by rainfall or dew and then dries, it becomes encrusted in a heavy coating of sand. This extra weight <a href="https://www.doi.org/10.1002/ecy.2809">makes it difficult for carpenter ants to carry the seeds back to their nests to consume</a>. </p>
<figure>
<img src="https://cdn.theconversation.com/static_files/files/1413/ezgif.com-optimize-1.gif?1609965144">
<figcaption><span class="caption">The struggle is real. <i>Eric LoPresti</i></span></figcaption>
</figure>
<p>We demonstrated this by making feeding stations where we could measure removal rates of sand-covered seeds and bare seeds. In nearly all of the 53 plant species we tested, the <a href="https://www.doi.org/10.1002/ecy.2809">sandy seeds were removed far more slowly than the bare seeds</a>.</p>
<p>While plant stickiness in sandy areas creates a barrier to stop herbivores, in other habitats it operates differently. For example, some carnivorous plants use stickiness to catch prey. </p>
<p>Every bit of a plant is shaped, over millions of years, by having to confront the challenges of the world around it while remaining rooted in a single place. Stickiness is one of thousands of strategies plants have stumbled on to survive the onslaught of hungry animals in nature. </p>
<p>[<em>Understand new developments in science, health and technology, each week.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-understand">Subscribe to The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/152720/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eric LoPresti received funding from the National Science Foundation. </span></em></p>For some sand-dwelling plants, stickiness is a defense tactic that keeps predators at bay.Eric LoPresti, Assistant Professor of Plant Biology, Ecology and Evolution, Oklahoma State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1461152020-09-16T19:52:33Z2020-09-16T19:52:33ZAustralian stinging trees inject scorpion-like venom. The pain lasts for days<figure><img src="https://images.theconversation.com/files/358049/original/file-20200915-22-1fqns6s.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fig B Dexcelsa</span> </figcaption></figure><p>Australia is home to some of the world’s most dangerous wildlife. Anyone who spends time outdoors in eastern Australia is wise to keep an eye out for snakes, spiders, swooping birds, crocodiles, deadly cone snails and tiny toxic jellyfish. </p>
<p>But what not everybody knows is that even some of the trees will get you. </p>
<p>Our <a href="https://advances.sciencemag.org/content/6/38/eabb8828">research</a> on the venom of Australian stinging trees, found in the country’s northeast, shows these dangerous plants can inject unwary wanderers with chemicals much like those found in the stings of scorpions, spiders and cone snails.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pIJRqwIzUpw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>The stinging trees</h2>
<p>In the forests of eastern Australia there are a handful of nettle trees so noxious that signs are commonly placed where humans trample through their habitat. These trees are called gympie-gympie in the language of the Indigenous Gubbi Gubbi people, and <em>Dendrocnide</em> in botanical Latin (meaning “tree stinger”). </p>
<p>A casual split-second touch on an arm by a leaf or stem is enough to <a href="https://theconversation.com/the-worst-kind-of-pain-you-can-imagine-what-its-like-to-be-stung-by-a-stinging-tree-103220">induce pain</a> for hours or days. In some cases the pain has been reported to last for weeks.</p>
<p>A gympie-gympie sting feels like fire at first, then subsides over hours to a pain reminiscent of having the affected body part caught in a slammed car door. A final stage called allodynia occurs for days after the sting, during which innocuous activities such as taking a shower or scratching the affected skin reignites the pain.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-worst-kind-of-pain-you-can-imagine-what-its-like-to-be-stung-by-a-stinging-tree-103220">'The worst kind of pain you can imagine' – what it's like to be stung by a stinging tree</a>
</strong>
</em>
</p>
<hr>
<h2>How do the trees cause pain?</h2>
<p>Pain is an important sensation that tells us something is wrong or that something should be avoided. Pain also creates an enormous health burden with serious impacts on our quality of life and the economy, including secondary issues such as the opiate crisis. </p>
<p>To control pain better, we need to understand it better. One way is to study new ways to induce pain, which is what we wanted to accomplish by better defining the pain-causing mechanism of gympie-gympie trees.</p>
<p>How does these plants cause pain? It turns out they have quite a bit in common with venomous animals. </p>
<p>The plant is covered in hollow needle-like hairs called trichomes, which are strengthened with silica. Like common nettles, these hairs contain noxious substances, but they must have something extra to deliver so much pain.</p>
<p>Earlier research on the species <em>Dendrocnide moroides</em> identified a molecule called moroidin that was thought to cause pain. However, experiments to inject human subjects with moroidin <a href="https://doi.org/10.1016/S0040-4020(01)87397-X">failed to induce</a> the distinct series of painful symptoms seen with a full <em>Dendrocnide</em> sting.</p>
<h2>Finding the culprits</h2>
<p>We studied the stinging hairs from the giant Australian stinging tree, <em>Dendrocnide excelsa</em>. Taking extracts from these hairs, we separated them out into their individual molecular constituents. </p>
<p>One of these isolated fractions caused significant pain responses when tested in the laboratory. We found it contains a small family of related mini-proteins significantly larger in size than moroidin.</p>
<p>We then analysed all the genes expressed in the gympie-gympie leaves to determine which gene could produce something with the size and fingerprint of our mystery toxin. As a result, we discovered molecules that can reproduce the pain response even when made synthetically in the lab and applied in isolation. </p>
<p>The genome of <em>Dendrocnide moroides</em> also turned out to contain similar genes encoding toxins. These <em>Dendrocnide</em> peptides have been christened gympietides.</p>
<figure class="align-center ">
<img alt="A plant with a straight narrow green stem covered in fine hairs and large flat leaves." src="https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358292/original/file-20200916-16-w5ez0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The most toxic of the stinging trees, gympie-gympie or Dendrocnide moroides.</span>
<span class="attribution"><span class="source">Edward Gilding</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Gympietides</h2>
<p>The gympietides have an intricate three-dimensional structure that is kept stable by a network of links within the molecule that form a knotted shape. This makes it highly stable, meaning it likely stays intact for a long time once injected into the victim. Indeed, there are anecdotes reporting even 100-year-old stinging tree specimens kept in herbariums can still produce painful stings.</p>
<p>What was surprising was the 3D structure of these gympietides resembles the shape of well-studied toxins from spider and cone snail venom. This was a big clue as to how these toxins might be working, as similar venom peptides from scorpions, spiders, and cone snails are known to affect structures called ion channels in nerve cells, which are important mediators of pain. </p>
<p>Specifically, the gympietides interfere with an important pathway for conducting pain signals in the body, called voltage-gated sodium ion channels. In a cell affected by gympietides, these channels do not close normally, which means the cell has difficulty turning off the pain signal. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-pain-and-what-is-happening-when-we-feel-it-49040">Explainer: what is pain and what is happening when we feel it?</a>
</strong>
</em>
</p>
<hr>
<h2>Better understanding may bring new treatments</h2>
<p>The Australian stinging trees make a neurotoxin that resembles a venom in both its molecular structure and how it is deployed by injection. Taking these two things together, it would seem two very different evolutionary processes have converged on similar solutions to win the endgame of inflicting pain. </p>
<p>In the process, evolution has also presented us with an invaluable tool to understand how pain is caused. The precise mechanisms by which gympietides affect ion channels and nerve cells are currently under investigation. During that investigation, we may find new avenues to bring pain under control.</p><img src="https://counter.theconversation.com/content/146115/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Irina Vetter receives funding from the Australian Research Council and the National Health and Medical Research Council of Australia. </span></em></p><p class="fine-print"><em><span>Edward Kalani Gilding receives funding from The Australian Research Council. </span></em></p><p class="fine-print"><em><span>Thomas Durek receives funding from the Australian Research Council and the National Health and Medical Research Council of Australia.</span></em></p>A new study of how stinging tree venom causes intense agony may help uncover new ways to manage pain.Irina Vetter, Australian Research Council Future Fellow, The University of QueenslandEdward Kalani Gilding, Postdoctoral Research Officer, The University of QueenslandThomas Durek, Senior Research Fellow, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/935172018-03-28T12:57:42Z2018-03-28T12:57:42ZWould standing on the first butterfly really change the history of evolution?<figure><img src="https://images.theconversation.com/files/212431/original/file-20180328-109207-12h38q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/textured-grunge-old-paper-background-boots-274803299?src=I6RQSRvM1gPTgmuOvH6rIA-1-31">Shutterstock</a></span></figcaption></figure><blockquote>
<p><strong>Martha Jones:</strong> It’s like in those films: if you step on a butterfly, you change the future of the human race.</p>
<p><strong>The Doctor:</strong> Then don’t step on any butterflies. What have butterflies ever done to you? </p>
</blockquote>
<p>Science fiction writers can’t seem to agree on the rules of time travel. Sometimes, as in Doctor Who (above), characters can travel in time and affect small events without appearing to alter the grand course of history. In other stories, such as Back To The Future, even the tiniest of the time travellers’ actions in the past produce major ripples that unpredictably change the future.</p>
<p>Evolutionary biologists have been holding a similar debate about how evolution works for decades. In 1989 (the year of Back To The Future Part II), the American palaeontologist Stephen Jay Gould published his timeless book Wonderful Life, named after <a href="http://www.imdb.com/title/tt0038650/">the classic movie</a> that also involves time travel of sorts. In it, he proposed a thought experiment: what would happen if you could replay life’s tape, rewinding the history of evolution and running it again? Would you still see the same movie with all the evolutionary events playing out as before? Or would it be more like a reboot, with species evolving in different ways?</p>
<p>Gould’s answer was the latter. In his view, unpredictable events played a major role in natural history. If you were to travel back in time and step on the first butterfly (reminiscent of the 1952 short story <a href="http://web1.nbed.nb.ca/sites/ASD-S/1820/J%20Johnston/short%20stories/A%20Sound%20of%20Thunder%20with%20questions%20--Ray%20Bradbury.pdf">A Sound of Thunder</a> by Ray Bradbury), then butterflies wouldn’t evolve ever again.</p>
<p>This is supposedly because the variation we see in nature - the many different physical features and forms of behaviour that lifeforms can have – is caused by random genetic events, such as genetic mutations <a href="https://www.nature.com/scitable/topicpage/genetic-recombination-514">and recombination</a>. Natural selection filters this variation, preserving and spreading the features that give organisms the best reproductive advantage. In Gould’s view, because the series of mutations that led to the first butterfly were random, they would be unlikely to occur a second time.</p>
<h2>Convergent evolution</h2>
<p>But not everyone agrees with this picture. <a href="https://www.templetonpress.org/books/runes-evolution">Some scientists</a> defend the idea of “convergent evolution”. This is when organisms that aren’t related to each other independently evolve similar features in response to their environment. For example, bats and whales are very different animals, but both have evolved the ability to “see” by listening to how sound echoes around them (<a href="http://www.sciencemag.org/news/2013/09/bats-and-dolphins-evolved-echolocation-same-way">echolocation</a>). Both pandas and humans have evolved <a href="https://daily.jstor.org/why-do-pandas-have-thumbs/">opposable thumbs</a>. Powered flying has evolved <a href="https://academic.oup.com/icb/article/56/5/1044/2420642">at least four times</a>, in birds, bats, pterosaurs, and insects like butterflies. And eyes have independently evolved <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev.ne.15.030192.000245">at least 50 times</a> in animal history.</p>
<p>Even intelligence has evolved multiple times. The famous palaeontologist Simon Conway-Morris was once asked if dinosaurs would have become intelligent if they were still here. <a href="http://www.bbc.co.uk/news/science-environment-28488044">His answer</a> was that “the experiment has been done and we call them crows”, referring to the fact that birds, including the <a href="https://theconversation.com/clever-crows-can-plan-for-the-future-like-humans-do-80627">very intelligent crow species</a>, evolved <a href="https://theconversation.com/how-did-dinosaurs-evolve-beaks-and-become-birds-scientists-think-they-have-the-answer-84633">from a group of dinosaurs</a>.</p>
<p>Convergent evolution suggests that there are a few optimal ways in which species can adapt to their environment, which means that (if you have enough information) you could predict how a species is likely to evolve over a long time. If you were to step on the first butterfly, another butterfly-like insect will eventually evolve because other mutations will eventually produce the same features that will be favoured by natural selection.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/212433/original/file-20180328-109199-u1mzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Gold stick spider.</span>
<span class="attribution"><span class="source">George Roderick</span></span>
</figcaption>
</figure>
<p>A <a href="http://www.cell.com/current-biology/fulltext/S0960-9822(18)30149-0?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982218301490%3Fshowall%3Dtrue">recent study</a> in the journal Current Biology seems to tip the scale in favour of convergent evolution. This study investigates how stick spiders have evolved in the Hawaiian Islands and provides evidence for different, isolated groups of animals evolving the same features independently.</p>
<p>Islands are often referred to as natural laboratories because they are effectively closed environments. Every time a species colonises a new island, a new independent experiment on adaptation takes place. An iconic example is the finches that have adapted to the various food sources on each island of the Galapagos, a fact that helped Charles Darwin develop his theory of natural selection. Some of these populations have even been caught in the act of becoming new <a href="http://www.bbc.co.uk/news/science-environment-42103058">species of finch</a>.</p>
<p>Most of the stick spiders on the Hawaiian Islands have gold, dark or white body colouring as camouflage to hide from predators, such as birds. The scientists used the DNA of the various spider species to reconstruct the history of how they evolved. They showed that the dark spiders and the white spiders have repeatedly evolved from ancestral gold spiders, six times in the case of the dark spiders and twice in the case of the white ones.</p>
<h2>Chance or necessity?</h2>
<p>This study is a remarkable example of convergent evolution taking place in the same geographical area. It’s reminiscent of the classic studies on <a href="http://www.cell.com/current-biology/abstract/S0960-9822(09)00722-2">Anolis lizards</a> by evolutionary ecologist Jonathan Losos, who noticed lizards on different Caribbean islands had independently evolved the <a href="http://www.sciencemag.org/news/1998/03/lizards-take-convergent-evolution-extreme">same adaptations multiple times</a>. All this suggests that lifeforms living in a specific environment over a long enough time period are likely to evolve certain features. </p>
<p>But the evidence for convergent evolution doesn’t rule out the role of chance. There is no doubt that mutations and the biological variations they create are random. Organisms are a mosaic of multiple traits, each with different evolutionary histories. And that means whatever evolved in the butterfly’s place might well not look exactly the same. </p>
<p>The evidence isn’t conclusive either way, but maybe both chance and necessity play a role in evolution. If we were to run the tape of life again, I think we would end up with the same types of organisms we have today. There would probably be primary producers extracting nutrients from the soil and energy from the sun, and other organisms that move around and eat the primary producers. Many of these would have eyes, some would fly, and some would be intelligent. But they might look quite different from the plants and animals we know today. There might not even be any intelligent two-legged mammals.</p>
<p>So just in case you ever find yourself travelling back in time, don’t step on any butterflies.</p><img src="https://counter.theconversation.com/content/93517/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jordi Paps receives funding from the University of Essex, the Royal Society, and the Wellcome Trust.</span></em></p>More and more evidence shows evolution isn’t as random as often thought.Jordi Paps, Lecturer, School of Biological Sciences, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/262652014-05-06T05:18:29Z2014-05-06T05:18:29ZHumans and squid evolved same eyes using same genes<figure><img src="https://images.theconversation.com/files/47660/original/cvwx3dzm-1399040861.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">I see how you see.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/actor212/7841841370">actor212</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Eyes and wings are among the most stunning innovations evolution has created. Remarkably these features have evolved multiple times in different lineages of animals. For instance, the avian ancestors of birds and the mammalian ancestors of bats both evolved wings independently, in an example of convergent evolution. The same happened for the eyes of squid and humans. Exactly how such convergent evolution arises is not always clear.</p>
<p>In a new study, published in <a href="http://www.nature.com/srep/2014/140305/srep04256/full/srep04256.html?WT.ec_id=SREP-20140311">Nature Scientific Reports</a>, researchers have found that, despite belonging to completely different lineages, humans and squid evolved through tweaks to the same gene.</p>
<h2>Eyes are the prize</h2>
<p>Like all organs, the eye is the product of many genes working together. The majority of those genes provide information about how to make part of the eye. For example, one gene provides information to construct a light-sensitive pigment. Another gene provides information to make a lens.</p>
<p>Most of the genes involved in making the eye read like a parts list – this gene makes this, and that gene makes that. But some genes orchestrate the construction of the eye. Rather than providing instructions to make an eye part, these genes provide information about where and when parts need to be constructed and assembled. In keeping with their role in controlling the process of eye formation, these genes are called “master control genes”.</p>
<p>The most important of master control genes implicated in making eyes is called <em>Pax6</em>. The ancestral <em>Pax6</em> gene probably orchestrated the formation of a very simple eye – merely a collection of light-sensing cells working together to inform a primitive organism of when it was out in the open versus in the dark, or in the shade.</p>
<p>Today the legacy of that early <em>Pax6</em> gene lives on in an incredible diversity of organisms, from birds and bees, to shellfish and whales, from squid to you and me. This means the <em>Pax6</em> gene predates the evolutionary diversification of these lineages – during the Cambrian period, some 500m years ago.</p>
<p>The <em>Pax6</em> gene now directs the formation of an amazing diversity of eye types. Beyond the simple eye, it is responsible for insects’ compound eye, which uses a group of many light-sensing parts to construct a full image. It is also responsible for the type of eye we share with our vertebrate kin: camera eye, an enclosed structure with its iris and lens, liquid interior, and image-sensing retina.</p>
<p>In order to create such an elaborate structure, the activities <em>Pax6</em> controlled became more complex. To accommodate this, evolution increased the number of instructions that arose from a single <em>Pax6</em> gene.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/47662/original/v6xztx3w-1399041006.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Complex beauty.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pacificklaus/8751081489">pacificklaus</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Making the cut</h2>
<p>Like all genes, the <em>Pax6</em> gene is an instruction written in DNA code. In order for the code to work, the DNA needs to be read and then copied into a different kind of code. The other code is called RNA.</p>
<p>RNA code is interesting in that it can be edited. One kind of editing, called splicing, removes a piece from the middle of the code, and stitches the two ends together. The marvel of splicing is that it can be used to produce two different kinds of instructions from the same piece of RNA code. RNA made from the <em>Pax6</em> can be spliced in just such a manner. As a consequence, two different kinds of instructions can be generated from the same <em>Pax6</em> RNA.</p>
<p>In the <a href="http://www.nature.com/srep/2014/140305/srep04256/full/srep04256.html?WT.ec_id=SREP-20140311">new study</a>, Atsushi Ogura at the Nagahama Institute of Bio-Science and Technology and colleagues found that <em>Pax6</em> RNA splicing has been used to create a camera eye in a surprising lineage. It occurs in the lineage that includes squid, cuttlefish, and octopus – the cephalopods. </p>
<p>Cephalopods have a camera eye with the same features as the vertebrate camera eye. Importantly, the cephalopod camera eye arose completely independently from ours. The last common ancestor of cephalopods and vertebrates existed more than 500m years ago. </p>
<p><em>Pax6</em> RNA splicing in cepahlopods is a wonderful demonstration of how evolution fashions equivalent solutions via entirely different routes. Using analogous structures, evolution can provide remarkable innovations. </p><img src="https://counter.theconversation.com/content/26265/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Malcolm Campbell receives funding from the Natural Sciences and Engineering Research Council of Canada, and from Genome Canada.</span></em></p>Eyes and wings are among the most stunning innovations evolution has created. Remarkably these features have evolved multiple times in different lineages of animals. For instance, the avian ancestors of…Malcolm Campbell, Professor & Vice-Principal Research, University of TorontoLicensed as Creative Commons – attribution, no derivatives.