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. (Learn more: http://mitsha.re/YCNZq)

Video: Melanie Gonick/MIT

Protein simulation/additional imagery: David Gold
Media provided by Pond5.com
Comb Jelly footage courtesy of Vancouver Aquarium Marine Science Centre (http://www.youtube.com/watch?v=G7WT81...)
Music sampled from, "Another Version of You" by Chris Zabriskie
http://freemusicarchive.org/music/Chr...
http://creativecommons.org/licenses/b...