L asked the other day, “Why did some dinosaurs evolve and others go extinct when the meteorite hit?”
Great question! One answer is, “I have no earthly idea!” but I feel as if she’s looking for something more detailed than that. I got to thinking that the answer to that question really encompasses the idea of adaptations, environments, and a little bit of luck, too. I’d been contemplating when to really start the discussion of evolution with her, and it seemed like the time was upon us.
She knows that birds are modern dinosaurs. She also knows (from an exhibit at the museum) that certain beaks are better for some tasks than for others. I decided to use the bird beak adaptation lab as an entry point into this discussion.
I consulted a number of examples of this lab online and eventually merged some ideas from many of them into our lab, which took place this morning.
I prepared the materials and laid them out on our kitchen table:
I then asked L to make predictions about which beak would be best at eating which type of food, after making sure she understood that one beak went best with one food. The circles represent those predictions that were supported with evidence (we revisited after the lab was complete) while the X’s represent those predictions for which we found no evidence.
We then created a chart listing the beaks down the side and the foods (what they actually were and what they represented) across the top. She then selected a beak and proceeded to try each food with that beak. She told me her observations and I recorded them in each cell. Once we finished all five trials with a beak, we used the purple marker to cross out those foods for which the beak simply didn’t work. When we figured out what food the beak was perfect for, we outlined that cell in blue. Once we outlined a cell, we used the orange marker to cross out those remaining cells for the beak. I wanted to present her with the difference between eliminating a choice through observation and eliminating one through the process of elimination.
We then wrote out our conclusions. She’d already stated that the straw drinking the nectar was a hummingbird while the tweezers getting the insects out of the wood must be a woodpecker. In our conclusions, we also included the/a type of bird that had a beak similar to the tool we used.
She then mentioned how a hummingbird couldn’t live in the ocean. I asked her why and she stated that there are no nectar-filled flowers in the ocean. This seemed like a great time to talk about adaptations and natural selection, so we started with oceans, hummingbirds, and pelicans:
From there, it seemed like a quick jump to natural selection and the creation of adaptations, so we talked about hummingbirds. I asked her, if a hummingbird had a choice to mate with a hummingbird with a short beak or one with a long beak, which would the hummingbird choose? She told me that the hummingbird would choose the one with the long beak because that one would be better at getting nectar. Exactly! We talked about how their baby would have a long, skinny beak too (although traits aren’t 100% heritable, this didn’t seem like the time to introduce that!). I drew a second generation and posed the same question. She again chose the long, skinny beak. She them told me, “So the hummingbird beaks just keep getting longer and skinnier!” Precisely, small human. Precisely. Here is my written record created through that conversation:
This launched a great many more questions, most of which I didn’t have great answers to! So, off to our local independent children’s bookstore we went! We came home with a few texts. The one we’re reading first is Did Dinosaurs Have Feathers? by Kathleen Weidner Zoehfeld. She’s started reading it aloud and is about a third of the way through. This book does a nice job of introducing the direct relationship between modern birds and dinosaurs (theropods specifically). As we finished our reading today, L told me that she rejects the distinction between theropods and birds. In her mind, the features are so similar that the difference is one of language, but not of features. She told me that “we know that birds are living dinosaurs” (that part wasn’t new information). What was new, though, was her addition that “theropods are ancient birds.” Makes sense to me!
And now we are at ballet class where I hear her yelling, “This is like speed and velocity!”
Nutty little girl. Love her so much. Thanks for reading.