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 [...]
This is a mouse brain When did the first brains evolve? Flatworms were the first animals to evolve anything like a brain, but it's really just a thickened part of [...]
A black woman shows off her muscles One-celled creatures don't have any muscles; the ones that can move themselves use flagellae instead. Even after living creatures evolved that had a [...]
Muscles project: Raw meat is made of muscles from animals. If you want to see what muscles really look like, it's pretty easy! All of the meat you eat is made [...]
Evolution of mollusks: Slugs are a kind of mollusk. When did the first mollusks appear? Mollusks are animals like mussels, clams, snails and slugs. Their name means "soft", because mollusks don't have [...]
Aren't octopuses beautiful? The best way to get to know more about octopus and squid is to go to the aquarium and look at them. You can see them catching [...]
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 [...]
Fish Stomach The first multi-cellular animals like hydras had no stomachs, or you could say they were all stomach, because they were shaped like a bag. Roundworms, a little later, [...]
Fish liver When did the first livers evolve? The earliest beginnings of what became the liver may have been relatives of segmented worms that lived about 600 million years ago. [...]
