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 first known mass extinction in earth's history was the Great Oxygenation Event 2.4 billion years ago. That event led to the loss of most of the planet's obligate anaerobes . Researchers have identified five major extinction events in earth's history since: 
It’s been confirmed: the first animal to ever evolve on Earth is… the sea sponge. We realize this might be a little disappointing, but wait, there’s more! Real life sea sponges will never be as popular as Sponge Bob, but they are much more interesting than you might first assume.
Evolution of animals merely depends upon environmental conditions of Earth. When digging down the history of Earth, we can see some animal species manage to thrive upon THE different geological time span of Earth, developed before million of years ago. Here the list of top 10 oldest animal species on Earth.
Well, just when you thought Dinosaurs were the first creatures on earth, you were wrong.
A new study mapping the evolutionary history of animals indicates that Earth's first animal--a mysterious creature whose characteristics can only be inferred from fossils and studies of living animals--was probably significantly more complex than previously believed.
What Was the First Animal on Earth? As of 2015, scientists believe the first animal on Earth was the comb jelly of the phylum Ctenophora. It is an ocean-dwelling, gelatinous organism whose length varies from less than half an inch to 16 inches. Until 2008, sponges of the phylum Porifera were considered the first animal.
New research has shed fresh light on how animals first appeared on the Earth. It is a story spanning hundreds of millions of years, of entire mountain ranges ground to dust by vast glaciers that ...
A new study mapping the evolutionary history of animals indicates that Earth's first animal -- a mysterious creature whose characteristics can only be inferred from fossils and studies of living ...
The first animals evolved during the absolute worst time on Earth ... too, spiraled out of control. Earth became a greenhouse — its oceans hot enough to cook their inhabitants, its blighted ...