Friday Sprog Blogging: co-evolution

Have you ever tried to have a conversation about one thing and found that, almost immediately, the conversation veered someplace else entirely? This is one of those.
I had heard the horrifying news that there are high school teachers — in our pretty good school district — who actually tell their students that it’s OK to cut and paste stuff from the internet into their papers without quotation marks or citation, and that Wikipedia is a great source of authoritative information (which, again, one need not cite, seeing as how the internet is like our shared brain).
My response was to launch a preemptive strike on the sprogs’ understanding of proper credit and critical evaluation of sources. It was during our discussion of the latter issue that the Free-Ride offspring seized control and took the conversation in a more interesting direction.
Dr. Free-Ride: You guys already know that there are some books that are good sources of information and some that aren’t. If you had to write a report on undersea life, you could probably get information from —
Elder offspring: One of our science books or guidebooks.
Dr. Free-Ride: Or maybe even an online source like the Monterey Bay Aquarium Online Field Guide, since the aquarium is pretty serious about accurate information. But would you want to use the giant squid book?
Younger offspring: No, because they say it’s dark at the bottom of the ocean because of curtains, and that’s not why it’s dark there. Sea plants and stuff block the sun.
Dr. Free-Ride’s better half: Well, it’s also really deep.
Dr. Free-Ride: It’s a long way for the light to travel.
Elder offspring: But there are creatures like lantern fish that can make their own light so they can see down there. I think it’s called an adaption.
Dr. Free-Ride: An “adaptation”, actually. And I’m pretty sure there are other fish that don’t even use vision to get along. That’s another adaptation to an environment where there’s not much light.

Elder offspring: Like cave fish?
Dr. Free-Ride: Yep, they’re blind, but not because the Stonecutters robbed them of their sight.
Dr. Free-Ride’s better half: In fact, cave fish don’t even have eyes.
Dr. Free-Ride: That’s efficiency for you. Don’t need to see, don’t bother developing eyes!
Elder offspring: I think another adaption —
Dr. Free-Ride’s better half: Adaptation.
Elder offspring: —adaptation is that some creatures that might seem like good creatures to eat don’t get eaten because they clean other creatures. For example, a cleaner shrimp.
Dr. Free-Ride’s better half: You know, an adaptation like that is kind of complicated because it’s not just the cleaner shrimp that’s adapting, but also the animals that are letting themselves be cleaned rather than eating the shrimp. That’s an example of co-evolution.
Elder offspring: Oh?
Dr. Free-Ride’s better half: So imagine you have a crocodile hanging out in its river and yawning, and there’s a monkey that scampers near its open jaws. The crocodile could eat the monkey, but the monkey cleans the crocodile’s teeth a little.
Younger offspring: Cool.
Dr. Free-Ride’s better half: But it’s probably not going to become a regular thing unless the crocodiles that let the monkeys clean their teeth do better than the crocodiles that just eat the monkeys.
Younger offspring: Maybe they do better because their teeth aren’t rotten.
Dr. Free-Ride: Don’t forget, “doing better” here also means living long enough to have babies. And also, there’d have to be some reproductive advantage for the monkeys who cleaned the crocodile’s teeth rather than just staying away from crocodiles altogether.
Elder offspring: Maybe the crocodiles would scare away other creatures that would want to eat the monkeys.
Younger offspring: I’d be scared.
Dr. Free-Ride’s better half: Co-evolution means that both kinds of creatures adapt to each other as a way to adapt to their environment.
Elder offspring: Actually, plovers clean crocodile teeth, I think.
Dr. Free-Ride: So, there aren’t actually monkeys who have adapted to clean crocodile teeth, are there?
Dr. Free-Ride’s better half: No.
Dr. Free-Ride: How cool would that be if there were? Somebody ought to get to work and figure out what kind of selection pressure could make that happen.
Dr. Free-Ride’s better half: Why not.
Dr. Free-Ride: Of course, I’m uncertain just how heritable crocodile teeth cleaning is as a behavior. It seems like the opposite of instinctive behavior.
Younger offspring: Monkeys could learn to clean crocodile teeth.
Elder offspring: But could crocodiles lose the instinct to eat monkeys?