Two and a half billion years ago, the Archaean Eon ended and the Proterozoic Eon began. Trillions of prokaryote cells lived in Earth's oceans. Some of these cells could photosynthesize their energy [...]
A group of brightly colored sponges in the ocean For almost three billion years, the only living things on earth were one-celled creatures, either prokaryotes or eukaryotes. Even today, the [...]
Science project: Buy a natural sponge - click here A science project with sponges You can check out sponges for yourself - go to any Whole Foods or other natural [...]
An annelid, or segmented worm When did annelids evolve? Roundworms probably evolved into segmented worms, or annelids, about 545 million years ago. What's a roundworm? More about the Proterozoic All our [...]
The yellow string is one of the arm nerves of a cat By around two billion years ago, some eukaryote cells were able to sense changes in their surroundings and [...]
