stasis

Spotted at about 600 million years ago. From ScienceDaily: One of the longest-running controversies in evolutionary biology has been, ‘What was the oldest branch of the animal family tree?’ Was it the sponges, as had long been thought, or was it the delicate marine predators called comb jellies? A powerful new method has been devised to settle contentious phylogenetic tree-of-life issues like this and it comes down squarely on the side of comb jellies. … For nearly a century, scientists organized the animal family tree based in large part on their judgement of the relative complexity of various organisms. Because of their comparative simplicity, sponges were considered to be the earliest members of the animal lineage. This paradigm began to Read More ›

Could vertebrates once have relied on a different mechanism for developing neurons in the gut? From ScienceDaily: Lamprey are slimy, parasitic eel-like fish, one of only two existing species of vertebrates that have no jaw. While many would be repulsed by these creatures, lamprey are exciting to biologists because they are so primitive, retaining many characteristics similar to their ancient ancestors and thus offering answers to some of life’s biggest evolutionary questions. … “We were interested in the origins of lamprey gut neurons because in other vertebrates they arise from a particular embryonic cell type, called neural crest cells,” says Stephen Green, postdoctoral scholar in biology and biological engineering and co-first author on the paper. “We knew that lamprey have Read More ›

From ScienceDaily: Euchambersia was a dog-sized pre-mammalian reptile living 260 million years ago in a deadly South African environment: Living in the Karoo, near Colesberg in South Africa, the Euchambersia developed a deep and circular fossa, just behind its canine teeth in the upper jaw, in which a deadly venomous cocktail was produced, and delivered directly into the mouth through a fine network of bony grooves and canals. “This is the first evidence of the oldest venomous vertebrate ever found, and what is even more surprising is that it is not in a species that we expected it to be, ” says Dr Julien Benoit, researcher at the Bernard Price Institute for Palaeontological Research at the University of the Witwatersrand in Read More ›

From ScienceDaily: Until recently it was thought the third major group of living land vertebrates, the crocodiles and birds (part of the wider group Archosauromorpha) only laid eggs. “Indeed, egg-laying is the primitive state, seen at the base of reptiles, and in their ancestors such as amphibians and fishes,” Professor Aitchison said. … “Further evolutionary analysis revealed the first case of live birth in such a wide group containing birds, crocodilians, dinosaurs and pterosaurs among others, and pushes back evidence of reproductive biology in the group by 50 million years,” Professor Liu said. “Information on reproductive biology of archosauromorphs before the Jurassic Period was not available until our discovery, despite a 260 million-year history of the group.” More. Paper. (public Read More ›

From ScienceDaily: In their paper, published in Nature Communications, Atmospheric oxygen regulation at low Proterozoic levels by incomplete oxidative weathering of sedimentary organic carbon, the University of Exeter scientists explain how organic material — the dead bodies of simple lifeforms — accumulated in the earth’s sedimentary rocks. After the Great Oxidation, and once plate tectonics pushed these sediments to the surface, they reacted with oxygen in the atmosphere for the first time. The more oxygen in the atmosphere, the faster it reacted with this organic material, creating a regulatory mechanism whereby the oxygen was consumed by the sediments at the same rate at which it was produced. This mechanism broke down with the rise of land plants and a resultant Read More ›

Deuterostomes are animals with true body cavities, featuring a mouth and usually an anus. From Telegraph: The 540 million-year-old “exquisite” fossil was unearthed during an excavation in China by led by University of Cambridge researchers, who say its discovery means humanity can now trace its roots back a further 30 million years. The creature is now thought to be the most primitive example of the deuterostome, one of three “superphylum”, and the group from which human beings and countless other species evolved. Most other early deuterostome groups date from about 510 to 520 million years ago, when they had already begun to diversify into vertebrates, as well sea squirts, as well as animals like starfish, sea urchins and acorn worms. Read More ›

From Tracy Vence at The Scientist: Foamy-like endogenous retroviruses (FLERVs), which are found in fish and amphibian genomes, may have originated with their vertebrate hosts more than 450 million years ago, according to a study published in Nature Communications this week (January 10). … “They date back to the origins of vertebrates, and this gives us the context in which we should consider their present-day activity and interactions with their hosts.” More. Maybe they were all part of a package with the fish and amphibians who hosted them? See also: Endogenous retroviruses made us human? Note the role of supposed junk DNA. and Stasis: When life goes on but evolution does not happen very much Follow UD News at Twitter!

From ScienceDaily: Delicate fossil remains of tomatillos found in Patagonia, Argentina, show that this branch of the economically important family that also includes potatoes, peppers, tobacco, petunias and tomatoes existed 52 million years ago, long before the dates previously ascribed to these species, according to an international team of scientists. … “Paleobotanical discoveries in Patagonia are probably destined to revolutionize some traditional views on the origin and evolution of the plant kingdom,” said N. Rubén Cúneo, CONICET, Museo Palentológico Egidio Feruglio. Paper. (paywall) – Peter Wilf, Mónica R. Carvalho, María A. Gandolfo, N. Rubén Cúneo. Eocene lantern fruits from Gondwanan Patagonia and the early origins of Solanaceae. Science, 2017; 355 (6320): 71 DOI: 10.1126/science.aag2737 More. See also: Stasis: Life goes Read More ›

From ScienceDaily: The research was carried out by a team of scientists at BGI, Zheijiang University and the Chinese Academy of Sciences, who tackled and analyzed an exceptionally large genome, totalling more than 10 billion DNA “letters.” Ginkgo is considered a “living fossil,” meaning its form and structure have changed very little in the 270 million years since it first came into existence. Given its longevity as a species and unique position in the evolutionary tree of life, the ginkgo genome will provide an extensive resource for studies concerning plant defenses against insects and pathogens, and research investigating early events in tree evolution and in evolution overall. … The ginkgo genome stretches over more than 10 Gb, which is 80 Read More ›

No, but seriously, from Phys.org: Years of research on the evolution of ancient life including the dinosaurs have been questioned after a fatal flaw in the way fossil data is analysed was exposed. Studies based on the apparently flawed method have suggested Earth’s biodiversity remained relatively stable – close to maximum carrying capacity – and hinted many signs of species becoming rapidly extinct are merely reflections on the poor quality of the fossil record at that time. However, new research by scientists at the University of Reading suggests the history of the planet’s biodiversity may have been more dynamic than recently suggested, with bursts of new species appearing, along with crashes and more stable periods. … The researchers ran thousands Read More ›

From Anna Nowogrodzki at Nature: The 423-million-year-old specimen, dubbed Qilinyu rostrata, is part of an ancient group of armoured fish called placoderms. The fossil is the oldest ever found with a modern three-part jaw, which includes two bones in the upper jaw and one in the lower jaw. Researchers reported their find on 20 October in Science. Scientists had thought that placoderm jaws were only very distantly related to the three-part jaw found in modern bony fish and land vertebrates, including people. … “You know that old thing where you have a picture of a vase and you suddenly realize that it’s two human profiles facing each other? It was like that,” Ahlberg recalls. “You realize that what everybody else Read More ›

From ScienceDaily: In a piece of Baltic amber about 50 million years old, research has uncovered an exoskeleton similar to that of a modern-day “walking stick” — evidence of an insect that literally was frightened out of its skin, and made its way to freedom just as it was about to become forever entombed by oozing tree sap. “From what we can see in this fossil, a tiny mushroom was bitten off, probably by a rodent, at the base of a tree,” Poinar said. “An insect, similar to a walking stick, was probably also trying to feed on the mushroom. It appears to have immediately jumped out of its skin and escaped, just as tree sap flowed over the remaining Read More ›

From ScienceDaily: The fossilised remnants of tube-like ‘dwellings’ which housed a primitive type of prehistoric sea worm on the ocean floor have been identified in a new study. According to researchers, the long, perforated tubes may have looked like narrow chimneys reaching up from the sea bed, and were made by a creature called Oesia, which lived a solitary existence inside them about 500 million years ago. … The study suggests that in some cases these structures exceeded 50cm in height and that they were typically at least twice the width of the worm, giving it plenty of room. The ends were sealed off, making life inside a rather lonely experience. “Only single worms are found within tubes, suggesting a Read More ›

From Michael Denton, author of Evolution: Still a Theory in Crisis As with other taxa-defining novelities, three is no evidence that any fundamental changes have occurred in the basic design of the cell system since its origination. The cell membrane, the basic metabolic paths, the ribosome, the genetic code, etc., are essentially invariant in all life forms on earth. And absolutely no plausible well-developed hypothetical evolutionary sequence has ever been presented showing how the cell night have evolved via a series of simpler cell-like systems. (p. 121) Follow UD News at Twitter!

600 mya. From ScienceDaily: Cells need to ‘know’ where they are in relation to all other cells in order to give rise into the correct cell types and tissues. The so-called ‘organizer’ is responsible for the formation of these body axes. Developmental biologists have shown that the molecular principles of the organizer are much more ancient than previously thought. The same signals were used already in the common ancestor of sea anemones and vertebrates 600 million years ago. … In vertebrate early development, an “organizer” forms in the region of the primitive mouth (the blastopore) of the embryo. This organizer is responsible for guiding axis formation of the organism. Its discovery won Hans Spemann a Nobel Prize in 1935. The Read More ›