Today’s topic at TMSE was evolution. This is an especially important topic to teach because evolution is so often glossed over in many public schools – I know it was in mine. If we can introduce the principles of evolution to kids when they are young, hopefully people will be more knowledgeable about the concepts of evolution in the future. There is a long way to go, but the University of Alabama and TMSE are taking a step in the right direction.
It was pajama day and there was a substitute teacher so everyone was a little more excited than usual, but I think they still got the gist of the lesson. We started by reviewing what we talked about last week: primates. They were asked to give examples of primates and did very well, they remembered that gorillas, chimpanzees, and lemurs were all primates. Importantly, humans are also primates. We then moved on to talking about evolution. I asked them what they already knew about evolution, and some of them had a basic idea of it, but many seemed to know very little about the concept. (This is why it is important to teach evolution early on.) The first thing to know about evolution is that Earth is very old. The kids tried to guess how old it is, with guesses ranging from five million years to infinity years, but the actual total is that Earth is 4.6 billion years old. For most of that time, all life has lived underwater. We went over some of the first life on land, such as Tiktaalik, which is a little amphibious-looking creature that had little fin-feet and roamed around about 375 million years ago. Ever since then, animals and plants have been evolving on land as well as in the water.
There are four fundamental parts of evolution that we talked about: variation, inheritance, selection, and mutation. Variation simply means that things of the same species are not complete copies of each other. We used the example of dogs – there are many different types of dogs that look very different from one another, but they are all still dogs. Inheritance means that traits an organism has are passed down to its offspring. Dogs continued to be the example here by talking about how a dog of a certain color is likely to have a puppy of the same color. With selection (traits that help an organism to live are more likely to be passed down) we used the example of a stick bug. Stick bugs evolved to look like they are, well, a stick. Because they look like a stick, things that want to eat it have a hard time seeing it, so more bugs with that looked like this lived and the trait was passed on. Finally, mutation is when unexpected things happen when traits are passed down. We gave the example that if someone were to be born with a purple nose, that would be a mutation because no one has a purple nose. The kids really liked this concept.
When these factors combine, you get evolution. There are two examples we discussed in class: giraffes and moths. A long time ago (more than seven million years ago) there were no long-necked giraffes. One member of a species that looked kind of like a deer/donkey had a slightly longer neck. This longer neck allowed it to reach higher plants that no one else could reach. This trait was inherited by later generations and, since it gave this animal a survival advantage, the neck was selectively passed down. Also, at the time of the Industrial Revolution in Britain, smoke from the factories caused trees in the area to turn black. A white moth that lived in that area stuck out against the black trees and kept getting eaten, but some were a darker color. This allowed those moths to blend in with the tree and, like the giraffe, they survived, and so the trait was passed on. A lot of the kids seemed to understand this example.
In the activity today, the kids got to see a simple version of how evolution works. They got a randomly assigned environment, and drew animals that would be able to live in that environment. We rolled die to determine four factors: the weather, the landscape, what the animal eats, and what eats the animal. For example, if the number rolled made it a freezing environment, they would theoretically make an animal that might be white to blend in with the snow, or make an animal with very thick fur to keep warm. Everyone seemed to enjoy making their animals, and, even though it got a little hectic, a lot of them did a great job with understanding the assignment.
I hope that the kids were able to get something out of the lesson and activity this week so that they can remember this when they (hopefully) learn more about the theory of evolution in the future. It was a fun day and I am glad to see learning about an important topic at such a young age.