It’s back and it’s even bigger than before, the veritable feast of exploration and adventure that is the Cambridge Science Festival. Head on over to the 2016 site to find out what this year is all about and what events you might like to see, hear, touch or even taste!
http://www.sciencefestival.cam.ac.uk/
Tropical rainforest tree canopies offer an environment with unique rewards but also challenges for the many inhabitants, amongst which are wingless insects and other non-flying arthropods. Whilst they benefit from the abundant flowers and fruits found at the treetops, wingless arthropods are in danger from predatory birds, reptiles, spiders and ants, that actively hunt or dislodge them, with the prospect of a long drop to either the understory or ground. In this context it may not be such a surprise to find that several tree-dwelling (‘arboreal’) arthropod groups have independently arrived at ways of generating a controlled glide when falling from a tree. So far a number of ants, bristletails and one spider species have been discovered to be capable of ‘directed aerial descent’, using gliding maneouvers to escape from predators and successfully survive what would otherwise be a perilous fall.
Among insects, arguably the most remarkable instance of convergent adaptation to gliding is found in a diversity of specialised ants that inhabit tropical forests.
Cephalotes atratus – Giant gliding ant (worker), a common inhabitant of rainforest canopies from Panama to Argentina
Tree-dwelling (‘arboreal’) ants display controlled gliding when dislodged from a tree trunk or threatened by predation. Gliding species include members of three separate families: Myrmicinae (e.g. Cephalotus atratus, Daceton armigerum, Procryptocerus convergens), Pseudomyrmecinae (e.g. Pseudomyrmex elongatus) and Formicinae (a single species,Camponotus canescens). All of these ants possess lateral flaps, or flanges, on their bodies. Myrmicinae and Pseudomyrmicini ants, which glide abdomen first, even have a moveable post-petiole region, so enabling accurate steering during aerial descent. They are further adapted to gliding by having a dorso-ventrally flattened body that confers an improved lift: drag ratio combined with good vision for locating landing sites as they approach a tree trunk. This suite of morphological adaptations illustrates convergence on a shared solution due to selection pressure for gliding ability. Gliding form and behaviour has not only arisen in three distinct ant families but even in sub-sets of species within certain genera (e.g. there are both gliding and non-gliding species of Daceton, Pseudomyrmex andCamponotus).
Bristletails (archaegnathans) are a group of primitive, wingless insects. Stephen Yanoviak and colleagues discovered that arboreal bristletails have the capability of a controlled descent when falling from canopy tree trunks, thus enabling them to avoid dangerous encounters on the forest floor. Gliding performance was tested in various species that inhabit tree trunk or understory environments such as low-growing plants or leaf litter. Impressively tree-dwellers (e.g. Meinertellus, Janetschekilis) were able to right themselves during a fall and generate a steep glide to safety, with their steering assisted by flexing of the abdomen and deployment of caudal ‘tail’ filaments. By contrast, when dropped from high up in the forest canopy, understory-dwelling bristletails failed to glide.
Selenops petrunkevitchi
With their long legs and often comparatively large size, spiders and their arachnid relatives such as scorpions, would seem unlikely contenders for gliding arthropods. Indeed, numerous species from five arachnid groups (spiders, opilionids, pseudo-scorpions, amblypygids and scorpions) have been tested for aerial performance, and of these only one spider demonstrates directed aerial descent behavior. The exceptional spider in question is Selenops, a large arboreal hunter spider that inhabits lowland rainforests in the Americas. During a fall from a tree high in the canopy Selenops spiders can efficiently right themselves, adopt their typical dorso-ventrally flattened shape and then make a controlled descent back to their original tree trunk. They seem to steer their bodies using movements of antero-laterally directed forelegs. Like gliding ants they also appear to use their large eyes to gather visual cues for their glide trajectory. Other arboreal spiders were tested and while several were capable of righting themselves in the air, only Selenops species demonstrated controlled descent.
Gliding ants, bristletails and spiders each depend on different body morphologies and means of aerial manoeuvring and yet they all achieve similarly high rates of success (around 90%) when gliding back to the safety of their tree trunks. This advantageous skill in the air is a striking case of convergence, dissimilar arthropods finding distinct ways to effect gliding behaviour. It may also be that given that the first insects were wingless, a capacity to glide may have been one avenue to powered flight.
Acanthephyra shrimp defends itself against dragonfish
The deep sea of the Gulf of Mexico is about to come under the microscope. Dr Edie Widdie and colleagues from Team ORCA (Ocean Research and Conservation Association) are running an expedition from 14 – 27 July. They will explore sites from 500 to 2000m depth and report to the scientific community, the NOAA Ocean Exploration website and to Whale Times, an inspiring educational website for children.
Below is Team ORCA’s news release on the expedition, for a bit more detail on Whale Times and what’s happening in this deep sea adventure:
Euplokamis ctenophore
Dr. Widder will be joining a team of scientists on the deep-sea expedition, Bioluminescence and Vision on the Deep Seafloor 2015, in the Gulf of Mexico from July 14 through July 27.
The project, funded by the National Oceanic and Atmospheric Administration (NOAA) will leave from Cocodrie, Louisiana and head south to a series of dive sites along the offshore slope between 500 and 2000 meters.
Scientists will use their combined expertise in bioluminescence, taxonomy, visual ecology, imaging and molecular biology, together with the remotely operated vehicle, the Global Explorer, to carry out studies of the deep-sea benthic environment of the Gulf.
Besides being a featured expedition on the NOAA Ocean Exploration website, the expedition will also be featured on the children’s web site Whale Times.
Visit http://whaletimes.org/ and look under the heading Creep into the Deep™ to find out more.
Designed for 3-6th grade classrooms, this site takes STEM curriculum to new depths by bringing deep-sea animals, exploration, and science into the classrooms in a unique and inviting way. What’s in the deep that a kid would like? Animals dressed in red velvet, some as transparent as glass, and others that flash and ripple with light so bright they could light a room. Every animal and discovery in the deep is weirder and more wonderful than the next. Only 5% of the ocean has been explored. In order to protect the ocean, there is so much more we must learn. Join us on this mission to investigate how the cool creatures that creep in the deep survive!
Both sites have a lot of excellent STEM based materials that will allow teachers to share the excitement of the mission with their students.
To follow the complete expedition, visit http://oceanexplorer.noaa.gov/explorations/15biolum/welcome.html
For those fascinated by the living world, a great treat is in store. About to hit the shelves is a new publication about convergent evolution, The Runes of Evolution: How the Universe Became Self-Aware. This book is by the renowned biologist Professor Simon Conway Morris and represents his latest synthesis on evolution and biological convergence in particular. Conway Morris thoughtfully explores the history and nature of convergence and documents a rich tapestry of examples from throughout the tree of life. Dipping in to Runes will both inform and amaze, taking you from octopus eyes and frog ecomorphs to puffer fish toxins and the evolution of play.
Conway Morris observes that “humans represent one minute twig of a vast (and largely fossilized) arborescence. Every living species is a linear descendant of an immense string of now-vanished ancestors, but evolution itself is the very reverse of linear. Rather it is endlessly exploratory, probing the vast spaces of biological hyperspace.” In its own exploratory way, The Runes of Evolution thoroughly investigates the ubiquity and implications of convergence and it does so in a fresh light, developing Conway Morris’s previous publication on convergent evolution, Life’s Solution: Inevitable Humans in a Lonely Universe.
Those familiar with Life’s Solution may ask: didn’t Life’s Solution say all there was to say about evolutionary convergence? According to Conway Morris, “Not quite, in fact [Life’s Solution] was little more than an extended Abstract. Runes sets convergence firmly in the cross-wires; evolution will never be the same again.”
The Runes of Evolution: How the Universe Became Self-Aware is published by Templeton Press and available to purchase now.
This year’s much anticipated Cambridge Science Festival was a great celebration of scientific discovery, exploration, ideas and research around the theme of LIGHT. Throughout a dynamic and busy fortnight thousands of people joined in a rich programme of talks, hand-on activities and experiments. Events took place all over the University of Cambridge, at Departments, Museums and even at a few related events beyond Cambridge, for example at the Linnean Society in London.
Sedgwick Museum ‘open laboratory’
The Map of Life was very happy to be granted an exhibit space at the Department of Earth Sciences, alongside their laboratory open day. The Sedgwick Museum and Department of Earth Sciences were hot venues for the Science Festival. On the busiest day of the Festival, dubbed “Science on Saturday”, the Sedgwick Museum hosted Time Truck, an event allowing visitors to investigate rocks, minerals, fossils and earthquakes. A week later, for “Science on Saturday: two” the Earth Sciences Department and Sedgwick Museum teamed up to create an open laboratory for visitors to explore unusual rocks and minerals, especially watching them light up beautifully under the microscope when cut into very thin sections. The Map of Life provided an injection of mind-bending biology to this laboratory open day, with an exhibit all about the marvels of bioluminescence.
Squid counterillumination camouflage
Bioluminescence, the enchanting capacity of an organism to emit cold light by a natural chemical reaction, is an intriguing feature of creatures as diverse as squid, mushrooms and beetles. Glowing species are known from almost all the major animal phyla as well as certain fungi, protists and bacteria. Across the tree of life bioluminescence has evolved independently at least 40 times and very likely more than 50 times: convergent evolution on an impressive scale.
Acanthephyra shrimp defends itself against dragonfish
Most bioluminescent organisms live in the marine environment, especially at depth and in the open ocean where it provides the main light source. Well known glowing sea creatures include strange angler fish with their bright lures, octopus, squid and jellies that flash wildly, shrimps that squirt luminous secretions at attackers and tiny dinoflagellates that can make the sea sparkle like stars when disturbed. While up to 80% of known luminous organisms are believed to live in the marine environment, the remainder are almost exclusively terrestrial and include creatures such as fireflies and glow-worms (both in fact beetles).
Glow worm Lampyris noctiluca
Bioluminescent light is typically produced by the oxidation of a photon-emitting compound known as luciferin. Luciferin oxidation is controlled by an enzyme, generally a luciferase or a photoprotein. The light produced serves many functions, both in the dark depths of the ocean and on land. Light emission is used as a means of defence, as an aid to hunt effectively or, under the cover of darkness, to attract potential mates.
A piece of the puzzle(s) from our bioluminescence exhibit
For the Cambridge Science Festival the Map of Life created a series of puzzles about the many functions of bioluminescence. Visitors were challenged to sort through a mixture of bioluminescent beings, some ugly and some beautiful and decide which of them used their light to defend themselves, to hunt or to attract a mate. Many were struck by the magical appearance of the tiny single-celled dinoflagellates that fill the sea with specks of light when disturbed (e.g. in breaking waves); this flashing defense is not unlike that of various jellyfish and squid. Another favourite was the squid that can make itself invisible from below using rotating blue lights on their undersides. This hiding strategy (called counterillumination) is also well known in crustaceans and fish.
Clytia aposematism: do not eat
Our puzzles highlighted a number of creatures that emit light to signal their toxicity, including the jelly Clytia, that converts its rounded body into a glowing square when threatened, and the green glowing millipede Motyxia. An impressive crustacean that we just had to include in our Science Festival exhibit is the shrimp Acanthephyra. This charismatic shrimp squirts luciferin and luciferase out of two separate tubes in its mouth, to mix some distance away. The mix makes a bright flare that dazzles and distracts would-be attackers while the shrimp makes its getaway in the opposite direction. Smart, but not unique: many other shrimps, ostracods, copepods, decapods and one deep sea mysid also squirt luminous chemicals, as do a number of deep sea squid.
Even by this account alone, bioluminescence truly seems one of the most radiant examples of convergent evolution and we are delighted that so many enjoyed finding out a bit about it at the Cambridge Science Festival. We are grateful to have been part of the fun and hope to be back, bigger and better next year!
In Japanese cuisine, the iconic pufferfish Fugu (which refers to several species) is notorious because if improperly prepared its consumption can have fatal consequences.
Some body parts, particularly the internal organs, contain high concentrations of one of the most powerful toxins found in nature, tetrodotoxin (which takes its name from the Tetraodontiformes). This alkaloid, which is up to 1200 times more potent than cyanide and has no known antidote, blocks action potentials in nerve cells by binding to voltage-gated sodium channels, thus causing motor paralysis and ultimately death from suffocation within minutes. It is found in several pufferfish genera and sometimes associated with bright colours and distinct markings, thus probably representing one of numerous examples of aposematism. 
Interestingly, tetrodotoxin is not produced by the fish themselves but by endogenous bacteria (e.g. species in the genera Vibrio and Pseudomonas), which are ingested with food. The mechanism by which the fish avoid self-poisoning revolves around a fascinating story of molecular convergence. Tetrodotoxin resistance is achieved by amino acid changes in all eight types of sodium channel, which substantially reduce affinity to the toxin. Intriguingly, these changes evolved independently in four phylogenetically diverse pufferfish species, but involve only very few sites, suggesting that selection for normal channel function strongly limits the possibilities for resistance-conveying mutations. Tetrodotoxin resistance thus represents “an example of natural selection acting upon a complete gene family, repeatedly arriving at a diverse but limited number of adaptive changes within the same genome” (Jost et al. 2008, Molecular Biology and Evolution, vol. 25, pp. 1016-1024).
The employment of tetrodotoxin as a defence (or sometimes predatory venom) is rampantly convergent, remarkably including marine as well as non-marine organisms. In the marine realm, it has so far been isolated from another fish (the marine goby Yongeichthys criniger), marine worms of different phyla (flatworms, ribbon worms, arrow worms and annelids), blue-ringed octopuses (genus Hapalochlaena), various genera of marine snails, crustaceans (the horseshoe crab Carcinoscorpius rotundicauda as well as xanthid crabs from different genera) and starfish (genus Astropecten). Beyond the oceans, the toxin is found in a wide range of amphibians from different families, particularly newts in the genus Taricha and frogs in the genus Atelopus. As it seems likely that their tetrodotoxin is also of bacterial origin, the symbiosis between tetrodotoxin-producing bacteria and animals, as well as the resistance of these animals to the toxin, has probably evolved independently several times. Interestingly, some predators of these poisonous animals might have convergently acquired tetrodotoxin resistance. Garter snakes (Thamnophis sirtalis) that prey on California newts (Taricha torosa) can eat them without any harm done, whereas garter snake populations that do not encounter the newts in the wild are poisoned when fed newts in the laboratory.
Read more about convergent evolution of tetrodotoxin at the Map of Life. You’ll find plenty of interesting convergences relating to pufferfish too: amazingly, they aren’t the only fish that can puff themselves up like a spiky football to scare away would-be predators!
To mark Darwin Day 2015, which falls around Charles Darwin’s birthday (12th February) each year, we’re flagging up a marvellous creature that he particularly admired for its many strange characteristics: the barnacle. Naturally, the barnacle shows a host of notable convergences!
Although they hardly resemble lobsters or shrimps, barnacles are in fact crustaceans and belong to the group ‘Cirripedia’. These peculiar crustaceans are justly famous for the scrutiny they received from Charles Darwin and here are just a few cases of convergent evolution found among barnacles:
For more on convergent evolution in this and other crustaceans, head over to explore crustacean convergence at the Map of Life.
St John’s College
Cambridge plays host to many meetings each year but few as unique and ambitious as the “Are There Limits to Evolution” conference that took place over two sunny days this September. Professor Simon Conway Morris and his team from the Department of Earth Sciences at Cambridge organized the conference, which was set in the scenic and stimulating backdrop of St John’s College. Nearly 30 speakers from all over the globe and from many different scientific disciplines shared their answers to the deceptively simple question: Are there limits to evolution? Speakers and delegates alike were rigorously challenged and enjoyed being part of a fascinating effort to articulate the key areas of research that will define the future of evolutionary biology.
Professor Simon Conway Morris commented that “All conferences have something new, but this one was special both because it brought together an extraordinary cross-section of leading scientists, from physicists to biologists, and because it looked to the problems rather than the solutions. That is a rare synergy.”
The conference schedule took all attendees on a rollercoaster for the brain, with speakers engaging their audience on subjects as diverse as burrowing mammals, prokaryote evolution, Neanderthals, protein evolution, cichlid fishes, homology, self-domestication, protein evolution, animal symmetry, convergence, cosmology, technology, ergodicity and Newtonian limits.
Dr Victoria Ling
Dr Victoria Ling, an expert in anthropology and science communication, ran the conference and in parallel a series of interviews with key speakers. These interviews allowed the team to record the opinions of leading biologists, philosophers and physicists on the future of evolution, as well as aspects of their life stories as scientists. Footage was skilfully shot by Peter Harmer and Mark Jones and will be available to view on a new explorative website being created in partnership with The District and to be launched in 2015. Watch this space (and follow Map of Life on Twitter or Facebook) for updates.
Although hard to choose just a few, highlights from the conference that relate to convergent evolution are given below:
Conference dinner at St John’s College
Eugene Koonin’s research on the fluid genomes of prokaryotes includes finding independent origins for three groups of giant viruses of prokaryotes. Virginie Orgogozo looked at changes in large effect genes of known function between closely related species, and found lots of convergent ‘genetic plagiarism’ (e.g. optix genes in Heliconius butterflies and lateral transfer of carotenoid genes in pea aphids and spider mites). George McGhee explored the limits on helical bryozoan colony form, showing how the key adaptation of water filtration efficiency poses a limit on colony form, as observed in the fossil record. Robert Asher focused on burrowing mammals, a dispersed group including the widespread talpid moles, golden moles of Africa and marsupial moles of Australia. The remarkable hearing of golden moles is based on inner ear specialisations that while beneficial when burrowing, limit colonization of aquatic habitats. 
Walter Salzburger mentioned some of the most striking cases of convergence among the iconic cichlid fishes, a group known for astonishing and yet constrained diversification. Geerat Vermeij, Russell Powell and others pointed in different ways to the general need for understanding the contraints on development when assessing convergent traits at different levels in the tree of life. Jonathan Losos expanded the classic case of convergence provided by Anolid lizard ecomorphs (link to Mol) by showcasing the truly convergent lizards alongside a few unique anoles that add questions about contingency, constraint and novelty in ecosystems. Josh Mylne described an incredible instance of protein convergent evolution based on research into a sunflower gene (PawS1) encoding a precursor seed storage protein. PawS1 contains a sequence for a trypsin-inhibitor (SFTI-1) with a cyclic inhibitor motif also found in distantly related legumes, cereals and even frogs.
What of the hot topic of human evolution? Anders Sandberg and Geerat Vermeij both pointed out that humans today effectively exist apart from natural selection and that as intelligent agents with technology we can change the ‘goals’ of evolution. Chrisantha Fernando described how neurons and networks in the brain appear able to learn and evolve, showing varied degrees of plasticity. Peter Kjaergaard shared research into the many origins, Neanderthal and otherwise, of today’s Danish population. Richard Wrangham described a model connecting incomplete development of so-called neural crest cells with a syndrome of traits related to selection for reduced aggression (domestication). He suggested that humans are self-domesticated, with certain traits such as smaller brains, less male-female dimorphism and lifelong learning being inextricably tied to the selected trait of reduced aggression as our species evolved to co-exist in great numbers.
Key speakers were Gunter Wagner, Eugene Koonin, Virginie Orgogozo, Matthew Wills, L. Mahadevan, Tom McLeish, George McGhee, Anders Sandberg, Eörs Szathmáry, Peter Kjaergaard, Mark Maslin, Ard Louis, Jennifer Hoyal Cuthill, Halló Gabor, Geerat Vermeij, Robert Asher, Sylvain Gerber, Walter Salzburger, Russell Powell, Tristan Stayton, Chrisantha Fernando, Jonathan Losos, Richard Wrangham, Michael Hendy, Josh Mylne and Peter Robinson. All agree that, yes, there are limits to evolution, and that there is still much to explore to define and understand the constraints and patterns of evolution. Thanks to the speakers and all the other participants for making the conference a unique and productive event.
If you’d like to treat your brain to an array of angles on evolution, a few books recently published by key participants at the conference include:
And finally, if you would like to immerse yourself in everything human evolution, Peter Kjærgaard and others are delighted to announce the very recent opening of the new Moesgaard Museum in Denmark. Map of Life already loves it…
Catesby’s snail-eating snake, photo by G. Gallice
The right and left mandibles are inserted into right-coiling snail shells and then by repeated and alternate retractions, they delicately extract the snail’s soft body. In an incredible instance of convergence, not only the pareatine and dipsadine snakes, but also certain insectivorous beetle larvae also have asymmetrical mandibles for snail predation. Because the right-coiling snails are preferred this means that the much rarer atypical left-coiling variants can gain a selective advantage where these predators abound.
Still within the reptiles we find another highly adapted snail-eater and with it another exemplary case of convergence. The Australian pink-tongued skink (Cyclodomorphus gerrardii) is a rainforest-dwelling lizard with a pair of large ‘hammer’ teeth for cracking snail shells. Within the same geographic region fossils of a Miocene marsupial (Malleodectes) have been found whose dentition is all but identical to Cyclodomorphus. It seems that both animals preyed on rainforest snails in the same way, and in the increasing competition resulting from climate change the lizards, in the end, came up trumps.
Sea urchins and starfish may not be the first creatures that come to mind when pondering animal eyes, but they are full of surprises. Many echinoderms (sea urchins, starfish, brittle-stars, sea cucumbers and sea lillies) are sensitive to light. Certain brittlestars (the ophiuroids) and sea urchins (the echinoids) even have compound eye-like visual systems that in some ways rival the arthropods. So it is that along the arms of one brittlestar (Ophiocoma wendtii) we find calcitic ‘microlenses’. These are composed of modified ossicles, can be shaded using pigmented chromatophore cells, and are underlain by the photoreceptors. In sea urchins visual acuity appears to be based on photoreceptors in the tips and bases of tube feet, and here shading is not mediated by protective pigments but rather by skeletal elements (spines and tube foot pores). Visual acuity of these animals apparently approaches that of the speedy predator Nautilus.
As echinoderms have a diffuse nervous system rather than a defined brain it is not clear what sort of image the animal may ‘see’ and yet their eyes provide fascinating points of convergence. For example, the calcite microlenses of brittlestars closely resemble those found in the compound eyes (the schizochroal variety) of certain trilobites. Furthermore, the way that the sea urchin tube foot system gathers visual information parallels the structure and function of the insect compound eye in interesting ways.
Head over to the latest entry on echinoderms at the Map of Life to read the full account of this strange case of convergent evolution! You may never look at a sea urchin again in the same way…
Map of Life 
