Evolution of bones – Skeletons and Biology
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 [...]
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05, 2017
What are segmented worms? Annelids, evolution, and biology
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 [...]
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What is a brain? Biology and Evolution
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 [...]
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05, 2017
What is a flatworm? Evolution and Biology
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 [...]
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05, 2017
Digestive System – Biology and Evolution
Digestive system: A hydra eating: the mouth is where all the tentacles come together,near the center of the picture.The hydra is eating the round bug in its stomach. Before digestive [...]
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05, 2017
What are arthropods? Biology
Bee on a flower What are arthropods? Insects, spiders, crabs, and lobsters are all arthropods, so there are a lot of arthropods on Earth. Annelid worms All our biology articles [...]
