Exoskeletons and Platypi

Penny and I were talking about the various classifications of animals in the car this morning. In her school science class, they're currently working on the five classifications of vertebrates (birds, fish, reptiles, amphibians, and mammals, for those of you who haven't had biology in a while) and she really seems to have latched onto this as being worthy of her attention in a way that most of the rest of the year's science lessons haven't.

I'd say that I need to read up on my science so that I can answer her questions, but her mind is like fireworks -- a single cluster of information can explode in so many different directions that it's impossible to precisely predict where she's going to go.

This morning, over the duration of about a fifteen-minute drive, we discussed:

• Whether whales and dolphins are the only mammals that live entirely in the sea. I eventually came up with porpoises and manatees, but couldn't immediately tell her the difference between a porpoise and a dolphin.
• That sharks are fish.
• Whether snakes are slimy on their bellies (she had been misinformed by an older child, apparently).
• That worms can be slimy, but they are not snakes, but a sort of bug, since they aren't reptiles and don't have any bones.
• How bugs can stand up and walk if they don't have any bones. I got to introduce her to the word exoskeleton, which is an excellent word to know.
  
• How crabs and lobsters, despite living in the ocean, are more like bugs than like fish.
• The various obvious characteristics of reptiles (air-breathing, scales, egg-laying). She knew all this on her own -- the discussion was in how she got to present this to her class.
• The various obvious characteristics of amphibians (gills as young, lungs as adults, egg-laying, smooth skin).
• That birds have feathers, though on some birds (e.g., penguins) they're tiny and hard to see. Also, that all birds have wings, though some (e.g., penguins and ostriches) can't fly.
• The platypus, which I told her was the only mammal that lays eggs (though apparently I was mistaken, as some poking around on wikipedia reveals that echidnas are also monotremes). But since we'd reached school by this point, I pulled up a picture of a platypus for her on my iPhone while we walked up to the school so she could giggle at it.

How does one prepare for that kind of breadth of subject? You really can't, especially since a kid's level of interest can spike and then disappear to be replaced with something else entirely different. You just thank the gods for the internet and its wealth of informative sites -- and quite suddenly realize why your parents bothered shelling out for a set of encyclopedias, back in the pre-'net era.