It Takes All Kinds
It All Began in the Oceans
 Mark SiddallHello. My name is Mark Siddall and I'm an Invertebrate Zoologist — I study animals without backbones.

Did you know that most animals (more than 99%!) are invertebrates? And that many of these live in the oceans? The other 1% of animals is called vertebrates, animals with backbones, like you and me. Most vertebrates live in water as well. In fact, much of life lives in the oceans!

Life actually began in the oceans — and for most of Earth history, has thrived in the oceans. First came true bacteria and probably archaea, followed by the protists. Plants, animals and fungi didn't appear until much later, and it is only in the last 360 million years that the first vertebrates, for example, moved onto land.

Timeline