stasis

From the Guardian: Fossils from China are said to prove that multi-cellular organisms evolved as early as 1.5bn years ago – but some experts dismiss findings “Our discovery pushes back nearly one billion years the appearance of macroscopic, multi-cellular eukaryotes compared to previous research,” said Maoyan Zhu, a professor at the Nanjing Institute of Geology and Palaeontology. The fossils were uncovered in the Yanshan region of Hebei province in China. Zhu and colleagues said they had found 167 measurable fossils, a third of them in one of four regular shapes – an indication of complexity. The largest measured 30cm by 8cm. Taken together they were “compelling evidence for the early evolution of organisms large enough to be visible with the Read More ›

The toxic and invasive cane toad (fossil found from Miocene era, 23 to 5 mya) is offered as an example. From ScienceDaily: The researchers looked at over 600 species from all classes of vertebrates worldwide and did a phylogenetic analysis to consider the evolutionary relationships between species. They tested for an effect on geographic location; reproduction mode; newborn dependence behavior; body size; and color variations between individuals of the same species. They found that species with varying colored individuals; those that give birth to live young; and/or those that live at low latitudes, were the most resilient to past environmental changes. Species found at higher latitudes tended to be younger because extinction rates are greater at high latitudes, while low Read More ›

From ScienceDaily: Researchers have uncovered dozens of fossilized teeth in Kuwajima, Japan, and identified this as a new species of tritylodontid, an animal family that links the evolution of mammals from reptiles. The finding suggests that tritylodontids co-existed with some of the earliest mammal species for millions of years, overturning beliefs that mammals wiped out mammal-like reptiles soon after they emerged. … “Tritylodontids were herbivores with unique sets of teeth which intersect when they bite,” explains study author Hiroshige Matsuoka, based at Kyoto University. “They had pretty much the same features as mammals — for instance they were most likely warm-blooded — but taxonomically speaking they were reptiles, because in their jaws they still had a bone that in mammals Read More ›

From ScienceDaily: The University of Illinois and University of Puerto Rico have completely sequenced the mitochondrial genome for the Hispaniolan solenodon, filling in the last major branch of placental mammals on the tree of life. The study, published in Mitochondrial DNA, confirmed that the venomous mammal diverged from all other living mammals 78 million years ago, long before an asteroid wiped out the dinosaurs. “It’s just impressive it’s survived this long,” said co-first author Adam Brandt, a postdoctoral researcher at Illinois. “It survived the asteroid; it survived human colonization and the rats and mice humans brought with them that wiped out the solenodon’s closest relatives.” That is why it is endangered now, researchers say. While the solenodon is venomous and Read More ›

From NPR: The main point of distinction: This newly discovered arachnid very likely could produce silk but lacked the spinnerets used by true spiders to, well, spin it, the scientists say. The researchers say it belongs to a “sister group” to the real-deal spiders. … Here’s more from National Geographic on the comparatively clumsy beginnings of spiderly silk production: “While delicately constructed webs seem synonymous with spiders, we know from the fossil record that the ability to secrete silk came before the ability to carefully control it. Spider relatives called uraraneids, which lived from 385 million years ago through the time of Idmonarachne, could produce silk but could not build webs.” University of Manchester’s Russell Garwood, who was one of Read More ›

From ScienceDaily: Scientists from the Department of Earth Sciences at Royal Holloway, University of London have found the oldest fossils of the familiar pine tree that dominates Northern Hemisphere forests today. The 140-million-year-old fossils (dating from the Cretaceous ‘Age of the Dinosaurs’) are exquisitely preserved as charcoal, the result of burning in wildfires. The fossils suggest that pines co-evolved with fire at a time when oxygen levels in the atmosphere were much higher and forests were especially flammable. More. From Dispatch Tribunal: The 7mm long fossil pushes back the date of pine tree origin by 11 million years as a previous fossil was dated 129 million years old, making the fossils discovered from Windsor as the oldest known fossils of Read More ›

So far known: “rope-like structure similar to that of some modern-day fungi” Cambridge Research News: This early pioneer, known as Tortotubus, displays a structure similar to one found in some modern fungi, which likely enabled it to store and transport nutrients through the process of decomposition. Although it cannot be said to be the first organism to have lived on land, it is the oldest fossil of a terrestrial organism yet found. The results are published in the Botanical Journal of the Linnean Society. Here (public access). From BBC: Most scientists agree that life moved from the sea to the land between 500 and 450 million years ago. But in order for plants and animals to gain a foothold on terra Read More ›

Except for losses. From Discovery: A fossil of a 520-million-year-old animal is so well preserved that its individual nerve fibers are still visible, according to a new study on the crustacean-like creature that once lived in southern China. The fossil represents the oldest and most detailed central nervous system ever found, reports the study, which is published in the journal Proceedings of the National Academy of Sciences. More. The animal is a Cambrian life form, Chengjiangocaris kunmingensis, considered “an early ancestor of modern insects, spiders and crustaceans,” and its nerve chord is “similar to the spinal cord that we and many other organisms have today. Bead-like ganglia, or bundles of nerve cells, controlled the animal’s single pair of walking legs.” Read More ›

From ScienceDaily: Most living vertebrate species have jaws, a development thought to have occurred sometime in the Paleozoic era. Jawed vertebrates–including humans–share many developmental characteristics that have remained unchanged for millennia. The brain’s basic developmental plan was thought by many scientists to have reached completion in jawed vertebrates because the brains of lampreys and hagfish–the only jawless fish that remain alive today–seem to lack two key domains. However, it turned out that hagfish [jawless fish] do have the required equipment. “The problem was that lampreys had not yet been shown to have a similar patterning,” explains Kuratani. “The shared pattern of brain development between hagfish and jawed vertebrates raised the possibility that the apparently primitive brain of the lamprey is Read More ›

From the article: Biologists say they have solved the riddle of how a tiny bacterium senses light and moves towards it: the entire organism acts like an eyeball. … Despite being just three micrometres (0.003mm) in diameter, the bacteria in the study use the same physical principles as the eye of a camera or a human. This makes them “probably the world’s smallest and oldest example” of such a lens, the researchers write in the journal eLife. Cyanobacteria, including the Synechocystis species used in the study, are an ancient and abundant lifeform. They live in water and get their energy from photosynthesis – which explains their enthusiasm for bright light. … “Cyanobacteria are 2.7 billion years old, so it’s much Read More ›

From ScienceDaily: “That’s a trait of ants,” Barden said. “Many ant species do that all the time. They’re always warring with either other individuals of the same species from different colonies or with different species.” … The fighting ants and others trapped in ancient Burmese amber from Myanmar are among the earliest known ants. “These early ants belong to lineages distinct from modern ants,” he said. “That is, they aren’t necessarily the direct ancestors of modern ants. They’re kind of their own branch doing their own thing.” The study also provides strong evidence that ancient ants — like modern ants — were social, according to Barden, who began a two-year, National Science Foundation Postdoctoral Fellowship in biology at Rutgers-Newark in Read More ›

Well, “brood care,” really. The embryos were developing inside their eggs under the carapace of the female Waptia. Instead of being dropped somewhere shortly after fertilization and left to whatever fate … From Science Daily: Waptia fieldensis is an early arthropod, belonging to a group of animals that includes lobsters and crayfish. It had a two-part structure covering the front segment of its body near the head, known as a bivalved carapace. Caron and Vannier believe the carapace played a fundamental role in how the creature practised brood care. “Clusters of egg-shaped objects are evident in five of the many specimens we observed, all located on the underside of the carapace and alongside the anterior third of the body,” said Read More ›

From Science Daily: New fossil evidence shows that Australia’s fire-prone shrubland open vegetation originated at least 70 million years ago — 40-50 million years earlier than previously thought. The findings, published online ahead of print in the American Journal of Botany, reject prevailing wisdom that Australia was covered with rainforest until 40 million years ago, and that currently dominant native vegetation types evolved after that on a drying continent with increasing fire. “Amazingly, we think part of the ancient vegetation was similar to what you can now see in south-western Australia, and there were even a couple of leaf bits that look just like Banksia,” says Dr Carpenter. “Banksia is one of Australia’s most iconic native plants and is very Read More ›

Not the comb jellies? From ScienceDaily: Who came first – sponges or comb jellies? A new study reaffirms that sponges are the oldest animal phylum – and restores the classical view of early animal evolution, which recent molecular analyses had challenged. Sponges (Porifera), comb jellies (Ctenophora), the true jellyfish and corals (Cnidaria) and plate animals (Placozoa) together make up the so-called non-bilaterian animals. All four phyla are evolutionarily ancient, and were already in existence more than 600 million years ago. However, unraveling the interrelationships between them — and how they relate to the Bilateria, to which all other animals, including humans, belong — has turned out to be one of the most challenging problems in evolutionary biology. “If we are Read More ›

Wake up. From ScienceDaily: Scientists have found eight well-preserved fossilized peach endocarps, or pits, in southwest China dating back more than two and a half million years. Despite their age, the fossils appear nearly identical to modern peach pits. … “We found these peach endocarp fossils just exposed in the strata,” Su said. “It’s really a fantastic finding.” Su said the discovery provides important new evidence for the origins and evolution of the modern fruit. Peaches are widely thought to have originated in China, but the oldest evidence had been archeological records dating back roughly 8,000 years. No wild population has ever been found, and its long trade history makes tracing its beginnings difficult. More. Of course, humans have done Read More ›