Chapter 7: Adventures in Bodybuilding

This chapter explained when, how, and why bodies started appearing.

I found Shubin's analogies very helpful in understanding what he was talking about. For instance, he compares cancers to "bullies who break down highly cooperative societies." It is evident that cells need to work together in order for the body to function properly.

While I was reading, I was surprised to learn that for a very long time, there were no living organisms with bodies. In fact, Shubin explains that if the entire earth's history was sized down to one year, only single-celled microbes existed until June.

I found H.V.P. Wilson's experiment on sponges interesting. He broke the sponges down to separated cells and placed them in a dish. Soon, the cells began to come together, finally forming an entirely new sponge. I thought that it was amazing that a bodied organism could come together from practically nothing. I also found Martin Boraas's experiment with alga intriguing. He and his colleagues let this single-celled alga live over several generations, and then introduced a predator. In response, the alga began to organize into a clump of eight cells. Similar to Wilson's experiment, a single-celled organism grew into a multi-cellular bodied organism. Because of a predator, the alga changed itself by becoming bigger so it would be better protected.

- Aarti Kumar