Hydra evolution: a hydra budding new hydras Before the hydra For almost three billion years, the only living things on earth were one-celled creatures, either prokaryotes or eukaryotes. What's a prokaryote? And [...]
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 [...]
Fish vertebrae Fish were the first animals to have vertebrae, about 510 million years ago. Vertebrae are tiny O-shaped bones that go around the fish's spinal cord and protect it [...]
Evolution of skeletons: Skeleton of a dinosaur Evolution of skeletons From frogs, there evolved reptiles like crocodiles and dinosaurs. Some of these reptiles lived mostly or entirely on land, so [...]
A fish skeleton Before there were bones One-celled animals don't have any support system that holds them in a certain shape. Plants do have a support system, but it's the [...]
Human hand bones The first fingers and toes evolved from earlier fish fins about 400 million years ago. During the Devonian period, the oceans were very shallow, and some fish [...]
Vertebrae project: check out fish and chicken vertebrae You can easily see vertebrae for yourself if you buy a whole trout (with the bones in) at the grocery store and [...]
A fish skeleton To check out fish bones, buy a whole fish from a big grocery store with a fish department. You can get them with the head and tail [...]
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 [...]
Nematodes, also called roundworms, in a jar Evolution of roundworms Roundworms, or nematodes, probably evolved from the earlier flatworms about 548 million years ago. Like all other living things at [...]
