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. The mystery of the first animal denizen of the planet can only be inferred from fossils and by studying related animals today. To get to the bottom of that, scientists analyzed massive volumes of genetic data to define the earliest splits at the base of the animal tree of life. The tree of life is a hierarchy of evolutionary relationships among species that shows which groups split off on their own evolutionary path first. 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. ‘This was a complete shocker,’ said study team member Casey Dunn of Brown University in Rhode Island. ‘So shocking that we initially thought something had gone very wrong.’ Dunn’s team checked and re-checked their results and came up with the same result every time: the comb jelly came first. The results are detailed in the April 10 […]