A 580-million-year-old fossil suggests that evolution of bilateral symmetry may be simpler than previously thought, Nature reports. The fossil, an eight-armed swirl named Eoandromeda after the galaxy ...

For decades, biologists have attempted to trace the earliest split on the animal tree of life, one that occurred approximately 600 million years ago. All living animals, from mammals to mollusks, ...

A new study bolsters the idea that the first animals were surprisingly complex, perhaps equipped with muscles and a nervous system. By Carl Zimmer One of the greatest transformations in the history of ...

Scientists use a novel application of chromosomal analysis to finally answer a question that has challenged biologists for over a century. When you purchase through links on our site, we may earn an ...

Deep, deep in geologic time, some 600 million or 700 million years ago, the very first animals evolved on Earth. Their closest relatives that still live today include sponges, sea anemones and comb ...