Title for ‘Earth’s first animal’ likely goes to simple sea creature
The first animal to appear on Earth was very likely the simple sea sponge. New genetic analyses led by MIT researchers confirm that sea sponges are the source of a curious molecule found in rocks that are 640 million years old. These rocks significantly predate the Cambrian explosion — the period in which most animal groups took over the planet, 540 million years ago — suggesting that sea sponges may have been the first animals to inhabit the Earth. “We brought together paleontological and genetic evidence to make a pretty strong case that this really is a molecular fossil of sponges,” says David Gold, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “This is some of the oldest evidence for animal life.” The results are published today in the Proceedings of the National Academy of Sciences. Gold is the lead author on the paper, along with senior author and...