The sympathetic nervous system, which enables the fight-or-flight response, was thought to be present only in jawed vertebrates. Analysis of a jawless vertebrate suggests that this system might be a ...

Archaea are often mistaken as bacteria, given that both are small, single-cell organisms. However, archaea are as genetically different from bacteria as humans are from bacteria. While archaea are ...

The researchers from the HiLIFE Institute of Biotechnology, University of Helsinki compared two central bearded dragon lizards (Pogona vitticeps): a normal one and a mutant with no body scales. They ...

Researchers report that ancient viruses may be to thank for myelin -- and, by extension, our large, complex brains. The team found that a retrovirus-derived genetic element or 'retrotransposon' is ...

Vertebrates have extremely different brain sizes: even with the same body size, brain size can vary a hundredfold. As a rule, mammals and birds have the largest brains in relation to their body size, ...

Researchers have long assumed that a tube in the famous Pikaia fossil ran along the animal’s back. But a new study turned the fossil upside down. By Carl Zimmer Over the past 500 million years, ...

A team of herpetologists at the Universidade Estadual de Santa Cruz just reported that a tiny frog found only in a hilltop forest in southern Bahia, Brazil, may be the smallest vertebrate in the world ...

Scientists have long puzzled over the gap in the fossil record that would explain the evolution of invertebrates to vertebrates. Vertebrates, including fishes, amphibians, reptiles, birds, mammals, ...

Learn how a second pair of eyes helped this 518-million-year-old fish evade predators. Spiders have eight eyes, bees have five, and boxed jellyfish have 24 — but these are the exceptions. The vast ...