Ancient Egyptian medicine: Egyptian boys being circumcised, from the tomb of the Vizier Ankhmahor and his wife Mereruka Sixth Dynasty (Old Kingdom, ca. 2300 BC) Best doctors in the Western [...]
Euglena have red eyespots (thanks to Sharon Mooney) When did cells learn to see? About two billion years ago, or maybe a little later, some eukaryote cells developed the ability [...]
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 [...]
Sandboxes can carry roundworms Roundworms are a serious health problem today in North America, especially in warm places where the cold doesn't kill them in the winter. Roundworms make kids tired, [...]
Cats have pupils that can get bigger or smaller. Eyes start to focus light By around 550 million years ago, some kinds of worms evolved eyespots sunk into their heads to protect [...]
A flatworm with eye-spots Eyespots came first Living creatures have been able to tell if it's light out or not for about two billion years. That's when some eukaryote cells evolved to [...]
Use a Pringles can for the cardboard tube Your eyes, and the eyes of many other animals and insects, work the same way as a pinhole camera. Building your own [...]
A flatworm When did flatworms evolve? The first flatworms, or platyhelminthes, probably evolved from something like a hydra about 550 million years ago. What's a hydra? Proterozoic Eon All our [...]
Evolution of ants: A bunch of ants When did ants evolve? Ants evolved from earlier wasps about 150 million years ago, during the Cretaceous period. The evolution of ants was around [...]
