Tree of life

From ScienceDaily: Pseudooides fossils have a segmented middle like the embryos of segmented animals, such as insects, inspiring grand theories on how complex segmented animals may have evolved. A team of paleontologists from the University of Bristol’s School of Earth Sciences and Peking University have now peered inside the Pseudooides embryos using X-rays and found features that link them to the adult stages of another fossil group. It turns out that these adult stages were right under the scientists’ noses all along: they have been found long ago in the same rocks as Pseudooides. Surprisingly, these long-lost family members are not complex segmented animals at all, but ancestors of modern jellyfish. Paper. (public access) – Baichuan Duan, Xi-Ping Dong, Luis Read More ›

A brand new early eukaryote (“its own eukaryotic lineage”) From Katarina Zimmer at The Scientist: From an aquarium at the Scripps Institution of Oceanography in San Diego, California, scientists have identified a unicellular species that could shed light on how eukaryotes evolved, they report in Current Biology this week (November 22). The tiny organism—named Ancoracysta twista—is not only its own species, says lead author of the study, Jan Janouškovec, but “it represents a whole new lineage in the eukaryotic tree of life.” A. twista is about 10 micrometers long and moves by using its whip-like flagellum. It is named after its distinguishing feature—the “ancoracyst,” a gun-like organelle that it uses to “shoot” at and immobilize its prey, usually other flagellate Read More ›

Should we call on 9-11, the Humane Society, or the vegans… or on soft dino tissue, to restore order? From Matthew Reynolds at Wired: The [March 2017] paper overturned one of the most fundamental things that we thought we knew about dinosaurs – that they split neatly into two groups. This is dinosaur 101. The first group, the Ornithischia, which means ‘bird-hipped’ and includes the Stegosaurus, Triceratops and Iguanodon. The second group is called the Saurischia, meaning ‘lizard-hipped’, and includes predatory dinosaurs (therapods) such as the Tyrannosaurus rex and Velociraptor as well as gigantic herbivorous dinosaurs (sauropodomorphs) including the Diplodocus and Argentinosaurus. … It’s hard to overstate how big a deal this is in the dinosaur world, says Paul Barrett, Read More ›

In response to Jumpin’ Genes!: A quarter of cow DNA came from reptiles, our physics color commentator writes, This whole business of parasites transmitting retrotransposons from reptiles to cows is just so zoo-centric. What about plants? What about viruses? Don’t they get to originate DNA too? When are they going to admit that this whole business of descent-with-modification really disrespects half the tree of life? Zoo-racist, that’s what they are. Most human beings must confess to a lack of genuine empathy with bugs, worms, and germs. Seriously, although no one talks about it much, these types of finds can’t be good news for the End of Science rent-a-riot (Darwin-in-the-schools lobby). See also: Jumpin’ Genes!: A quarter of cow DNA came from Read More ›

From Ed Yong at The Atlantic: This jumping gene seems to have entered the cow genome from the unlikeliest of sources: snakes and lizards. Retrotransposons typically jump around within a single genome, but sometimes they can travel further afield. Through means that scientists still don’t fully understand, they can leave the DNA of one species and enter that of another. And so it is with BovB. No one knows the animal in which it originated. But from that mystery source, it has jumped into the DNA of snakes and cows, elephants and butterflies, ants and rhinos. … No one knows how BovB travels between species, but Ivancevic and Adelson suspect that it might spread via blood-sucking parasites. They have found Read More ›

From Joel Shurkin at InsideScience: It’s hard to think of dinosaurs as being loving, caring parents, but scientists have found some of them may have been just that. Take the oviraptorosaurs, a group of feathered creatures that look as if they were constructed by a malignant committee from spare bird parts. By studying fossilized oviraptorosaur eggs, researchers from France and China have found that oviraptorosaurs lay across those eggs in nests and warmed them with body heat just as modern birds do. Paleontologists had previously theorized that oviraptorosaurs incubated their eggs, but the French-Chinese team came up with the numbers. They also added to the theory that at least some dinosaurs were warm-blooded reptiles. More. With dinosaurs, as with Neanderthal Read More ›

A friend calls attention to this interesting new paper: When Homoplasy is not Homoplasy: Dissecting Trait Evolution by Contrasting Composite and Reductive Coding Alejandro Torres-Montúfar  Thomas Borsch  Helga Ochoterena Syst Biol syx053. DOI: https://doi.org/10.1093/sysbio/syx053 Published: 22 June 2017  Article history Received: 03 February 2017 Revision Received: 13 April 2017 Revision Received: 18 May 2017 Accepted: 24 May 2017 Abstract: The conceptualization and coding of characters is a difficult issue in phylogenetic systematics, no matter which inference method is used when reconstructing phylogenetic trees or if the characters are just mapped onto a specific tree. Complex characters are groups of features that can be divided into simpler hierarchical characters (reductive coding), although the implied hierarchical relational information may change depending on the type of coding Read More ›

Oh wait, wait, stop wait, the correct word is “reshaping” the Tree of Life. It still smells like fresh lumber to us. From ScienceDaily: A new era in science has emerged without a clear path to portraying the impacts of microbes across the tree of life. What’s needed is an interdisciplinary approach to classifying life that incorporates the countless species that depend on each other for health and survival, such as the diverse bacteria that coexist with humans, corals, algae and plants, according to the researchers, whose paper is published online in the journal Trends in Ecology and Evolution. “In our opinion, one should not classify the bacteria or fungi associated with a plant species in separate phylogenetic systems (trees Read More ›

From Suzan Mazur, author of Paradigm Shifters, at Huffington Post: Suzan Mazur: Philipp Khaitovich et al. think neoteny affects the grey matter of the human brain but not the white matter. I gather you agree, but you see the issue as one of bioenergetics, involving mitochondria. You say neoteny is inherent in development of human brain regions where high energy demands are required for cognitive and memory-related functions. Is that right? Vladimir Skulachev: Yes. This is absolutely necessary for technical progress. By the way, I am now writing the next paper concerning the numerous common traits of humans and NMRs. It’s very strange but NMRs are much closer to humans with regard to several components of brain construction than to Read More ›

From ScienceDaily: Human teeth evolved from the same genes that make the bizarre beaked teeth of the pufferfish, according to new research by an international team of scientists. The study, led by Dr Gareth Fraser from the University of Sheffield’s Department of Animal and Plant Sciences, has revealed that the pufferfish has a remarkably similar tooth-making programme to other vertebrates, including humans. Published in the journal PNAS, the research has found that all vertebrates have some form of dental regeneration potential. However the pufferfish use the same stem cells for tooth regeneration as humans do but only replace some teeth with elongated bands that form their characteristic beak. … “Our study suggests the same genes are instrumental in the early Read More ›

The recent capture of a live giant shipworm highlights devolution. One form of devolution is allowing complex body systems to become vestigial, relying on microorganisms instead. From BBC: The giant shipworm is unique not just for its size, but also for feeding on nutrients in mud and marine sediment instead, using a type of bacteria. It therefore has a much smaller digestive system compared to other shipworms. And while the discovery of the animal itself is exciting, the team’s research has revealed there is an entire hidden ecosystem at play. The giant shipworm has bacteria that live inside its shell, converting chemicals from the nearby rotting wood into energy and nutrients, similar to what plants do with sunlight.More. Devolution poses Read More ›

Here is the next video from the AM-Nat conference. In this video, Paul Nelson talks about genes that are both taxonomically-restricted (ORFan genes) and essential to the function of organisms. Then he describes the impact of these findings on common descent.
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We’d heard about Craig Venter’s dissent before but you should read the whole story: From Tom Bethell in Darwin’s House of Cards: A Journalist’s Odyssey Through the Darwin Debates, This was publicized in a science forum held at Arizona State University in February 2011, a little over a year after Dawkins’s Greatest Show was published. The physicist Paul Davies and others, including two Nobel Prize winners, participated in the event, which was videotaped. Richard Dawkins himself was on the panel. The forum addressed the question, “What is life?” Most of the panelists accepted that all organisms on Earth represent a single kind of life because they believed that the genetic code is universal. The NASA scientist and panelist Chris McKay Read More ›

A friend writes to tell us of an insightful article in Nature: It emerges that a dogfish shark’s spine becomes stiffer as the fish swims faster, enabling the animal to swim efficiently at different speeds. The finding could also provide inspiration for the design of robotic biomaterials. (paywall) – Biomaterials: Sharks shift their spine into high gear Matthew A. Kolmann & Adam P. Summers, Nature, 14 December 2016 | doi:10.1038/nature21102, More. The friend believes that the shark’s cartilaginous skeleton should not be thought of, as it often is, as primitive, but as an intelligent use of materials that enable high-speed bursts of movement. As the author put it, the skeleton is “an aquatic equivalent of continuously variable transmission, a type Read More ›

From The Conversation: If all jawed vertebrates, including humans, are nothing more than highly evolved placoderms, then key features of ourselves should be traceable to structures that first appeared in our fishy placoderm ancestors. This would include particular jaw and skull bones and the proportions of our face and brain. But our new evolutionary tree challenges the idea that placoderms gave rise to all other jawed vertebrates. Instead, we suggest they are a side branch in vertebrate evolution – diverse and successful in their day but ultimately all destined for extinction. If correct, this alternative tree would require a radical rethink of many aspects of vertebrate evolution.More. If evolution takes place by a number of means other than Darwinian descent, Read More ›