I found this video on the Ted-ed Site. Since my class is currently reading Your Inner Fish, the story about how the first animals that are direct ancestors of mammals came out of the water, I thought this video on the very first animals to come out of the sea was very appropriate.

Have a look at the video and check out the questions afterwards… you never know, one might show up as extra credit on a quiz…

http://ed.ted.com/on/wAFSbjQj

I hope you enjoy.