Fish and reptiles and monkeys, oh my!

I have learned that part two of the aforementioned PBS series, this one titled Your Inner Reptile, will be airing Wednesday April 16 at 10 PM, on PBS of course. Local listings may vary, but it does seem like they’re running this weekly.

You also haven’t missed out if you didn’t get the chance to see Your Inner Fish, the first part – it can be viewed directly on PBS’s site by clicking right here. My understanding is this is supposedly restricted to US viewers, but you can get around this by using a proxy service. Since I have not ever attempted this myself, I cannot guide you on it, but a websearch should reveal how this works.

I will reiterate that I found part one excellent, one of the best science programs I’ve seen, and the book is pretty captivating itself. Gather the kids, nuke the popcorn, get out your giant foam tetrapod fin (well, for the TV program anyway – it might make turning the book’s pages a little tricky.) Go check out the interactive website, too. And if you’re a teacher, this is definitely a worthwhile series to get the class involved in.

I’ll throw out a little quibble, though: the use of fish, reptile, and monkey should be considered popular usage for convenience, but not scientifically accurate. The ancestral stages that we passed through on our long journey to Homo sapiens may have borne a superficial resemblance to these modern classifications, but today’s fish and reptiles and monkeys are just as much evolved from these ancestors as we are. Evolution didn’t halt or stagnate for any of them, and no modern species has existed unchanged for thousands or millions of years. It’s simply that, in some cases, the environments that our ancestral and our modern species had adapted to were fairly similar. While a shark and a tuna are similar in many ways (and commonly classified as “fish,”) they actually diverged from a common ancestor before the tetrapods like Tiktaalik, which in turn led to all four-limbed species including us. Tiktaalik may or may not be our direct ancestor – we might never know for sure – but it is an example of the development of supporting fins. Tiktaalik might be one of several cousins that existed at the time, and it was another cousin that was really our ancestor, all descended from a species we have not discovered yet. Fossils are rare things, providing tiny spots in history rather than a chapter-by-chapter saga – but, the progression of traits and timelines that we’ve found have been exactly what we should expect from the theories of natural selection and common descent, so this sporadic sampling is not a weakness in the slightest, and no other plausible theory exists to explain why this progression is so plainly evident.

That’s enough digression – go watch the program.