Reptiles, the First Week

People have been asking how my reptile lesson went, and I am happy to say that it went just fine! I am teaching the 3rd and 4th graders this year, and so I have to teach the same hour and fifteen minute lesson twice, once to each grade. The third graders were first, and some of the boys were pretty distracted, but most people were interested. That is Luke's class, so it's fun to interact with him in there. I was a lot more nervous about the 4th grade class, because of one the boys in there has some definite learning issues and I would say is probably on the Aspergers/autism spectrum. He just is a little . . . off . . . in his dealing with others, and his response to social cues. He also doesn't read or write much, so I wasn't sure how he would do. It turned out that he did just fine. He is quite smart, and I think he picked up everything I wanted him to get, even though he didn't do the worksheets with us.

I started out talking about how we like to have things organized, like grocery stores, our clothes, etc. People wanted to organize animals as well, but it took until the 1600's before someone figured out the best way to organize them, by studying details of their bodies, as opposed to where they live or other ways of dividing them up. I have a poster showing how to classify a polar bear, so we talked through all the levels of classification, as well as how to remember the levels ("King Phillip Came Over For Green Spinach" or whatever sentence you may dredge up from the recesses of your high school biology class memories, LOL).

The we talked about what made an animal a reptile. When I asked what animals were reptiles, most kids said things like frogs as well as snakes and crocodiles, so this led naturally into the differences. For those of you who have not recently boned up on your reptile identifying characteristics, let me just refresh your memory:

1. They are vertebrates
2. Their skin is covered by hard, protective scales
3. They reproduce using eggs
4. They breathe oxygen using lungs
5. They are cold-blooded and cannot regulate their own body temperatures

We looked at each characteristic individually, so I think by the end the kids knew those 5 things pretty well. I did learn some interesting tidbits about reptiles. For example, did you know that nest temperature determines whether a crocodilian or turtle egg will be a male or female? It is not inscribed in their DNA. Interesting! Usually one nest will be only males, or only females. Also, some snakes incubate their eggs inside their bodies, so it looks like they give birth to live young. This is useful if the snake lives in a climate where the temperature might not be as regulated, since a steady temperature is so important. Also, sea turtles and sea snakes can absorb some oxygen through their mouths (turtles) and skin (snakes) so they can stay underwater longer without breathing. Sea snakes can stay underwater up to 8 hours without breathing! Sea snakes are also the most venomous snakes. I would never go swimming in the waters of Indonesia, where the highest percentage of these snakes live! Also, saltwater crocodiles live in those waters, and those things are nasty. Yuck. One last fact--if a snake eats, but it gets too cold, then he can't digest the food, and it will jsut rot inside him and kill him. SO he has to throw it back up before that happens. Gross!

After we talked about those 5 characteristics, we talked about each order of reptiles in a little more details. For example, why are legless lizards not snakes? In fact, lizards and snakes, while having similar body structures, have some differences. Lizards have a distinct neck and tail, they have ear openings behind their eyes (snakes don't have any ears at all--they only sense vibrations), and they have eyes with lids. Snakes' eyes are covered by transparent scales. Now you know.

After we got through all the lizards, snakes, turtles, crocodilians, and tuataras, we did a little worksheet I made up. It had 6 boxes--one for each level of classification, except for the bottom box, which had the genus and species: Alligator mississippiensis (American alligator). So the top box was Kingdom--Animalia. Then in the box I had lots of things, like snake, shark, mushroom, horse, starfish, potato, spider, alligator, etc. They had to cross out what didn't belong in the animal kingdom. The next box was Phylum--Chordata, and there they had to cross out anything that didn't have a backbone, like insects, mollusks, , spiders, etc. The next box was Class--Reptilia, so they had to cross out everything that wasn't a reptile, and then it was Order--Crocodilia. The only things in that order are crocodiles, alligators, caimans (they only live in South America), and gharials (only live in India and Nepal). The second to the last box was Family--Alligatoridae, which has alligators and caimans, and they didn't have to cross anything out there either. The kids got the idea, and could generally figure out what to cross out, although there were some tricky things (coral IS in the animal kingdom). It defintiely reinforced the idea of the levels of classification. If they went away with that, as well as knowing what 5 characteristics reptiles share, then I will be happy.

Next week we will review, talk about a pet snake that one of the 4th graders is bringing in, watch a video that we have, and I think talk about ways reptiles survive (camoflauge, losing their tails, mimicing coloration of more dangerous reptiles, etc.). And then I'll be done! Goodbye reptiles!!