I learned some interesting new things from this documentary. It was great to see a Tiktaalik fossil and an explanation of what the ancient fish was doing on land. Many of the biographical bits about Charles Darwin were also new to me. I didn’t know he attended medical school or study for clergy. The mental image of a young Darwin riding a giant Galapagos tortoise is particular amusing. The video was also a good refresher of some information I read about evolution a few years ago, particularly the parts on the pharyngula stage of an embryo’s development, and Darwin’s finches.
Image from Tshitvortex
The distinction the video drew to “switch” genes and the genes brought some clarity to me about what causes atavisms. Atavisms are “throwback” genes; the rare occurrence when an animal is born with one its ancestors traits. Some humans, for instance, have been born with tails, dolphins born with hind-limbs, etc. Judging from the documentary’s explanation of junk genes, I’m assuming atavisms are caused by a mutation in the switch genes. Somewhere during a human embryo’s development, a mutated switch gene will give the command to keep its tail.
One of the questions I have is related to the video’s explanation of how human ancestors were able to make more room for brain growth by not requiring as much jaw strength as an ape. A theory I’ve heard of is that this was able to occur because man’s ancestors learned to cook their food with fire, so meat became easier to chew. How such a theory could be confirmed, I have no idea, but it would be interesting to know if it has or not.