One Small Step

I loved my uni degree in zoology. I would do it again in a heartbeat. I would sit through every lecture and take the same reams of notes. Turn up to the practicals with the same bumbling, clueless attitude. I would take more notes. Be more bumbling.

Only difference when I did it last time – I would not worry about getting that job afterwards. Ha! The power of hindsight. Oh, and I would have totally gone for that octopus Phd, posted to Prof Barratt’s door. Or completed that MSc in Immunology. It would have been handy to know more things about cytokine storms or antibody tests right now. Doh. I’m doing it again. Let’s stay here for a moment.

Zoology revolves around the principle of evolution. Darwinian natural selection was at the very heart of the course. Like a giant pillar holding it up. A cascade effect so to speak – zoology, genetics, ecology all linked back to evolution. Felt at times like a chronological race to put things into order.

Take the fishes for example. Why were they so successful as a group of organisms? Yes, the backbone was handy. And check this out. They were the first to have jaws. Fish were the first animal to develop plates of bone – one above and below the other. This formed the first pair of rudimentary jaws. It always makes my brain itch to hear this sort of fact. Really? Like no one thought of the jaw principle before? No, Hannah, keep up. We’re moving forwards now.

This meant that fish were the first animal to be able to crush and swallow their food. Apparently, it was super handy 400 million years ago, when the placoderm fishes were doing boom time in the Devonian. And the way these thirty-foot long fish died and decomposed, or rather didn’t, means their fossil record is easy to see now. Not only can scientists study what they looked like based on the bones they left behind; they can even study what was in their stomachs.

Other fish, turns out. Surprise. Semi-digested balls of fish bones. See, with their bony-plate jaws, they could grind down and swallow so many fish, they produced boluses out of their prey. Like owls do now. They probably regurgitated them in the same way owls do too. Well, that’s what the scientists think. They can’t prove it though. They weren’t there. Ok, move along Hannah. Don’t get stuck in the sticky stuff.

That’s just one example how evolution as a concept pushes forward. You’ve got backbones, then jaws, then animals who begin to leave the sea. What a primordial soup.

For the progression towards the all singing and dancing human bumbles, we need examples of animals who moved out of water and onto land, but are still closely connected to water. You can tell where this is going. Nod nod, wink wink. Evolution is like a living screen shot.

We even have animals who come out of the sea briefly, to do their own reproductive thing, before they shoot back into water again. This animal still lives among us. It’s the 120 million-year old sea turtle. Full-on evo-boggle. We go backwards and forwards in our world. Zoology, thank you.

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