Earth's first animal was the ocean-drifting comb jelly, not the simple sponge, according to a new find that has shocked scientists who didn't imagine the earliest critter could be so complex... scientists analyzed massive volumes of genetic data to define the earliest splits at the base of the animal tree of life... The new study surprisingly found that the comb jelly was the first animal to diverge from the base of the tree, not the less complex sponge, which had previously been given the honor... Unlike sponges, comb jellies have connective tissues and a nervous system, and so are more...