Models (11–14): Animal Ecology

Autopoiesis

I begin my biology topics with my youngest students (aged 11) with autopoiesis. This is the idea that we self-produce in a continuous cycle. It gives meaning to the lives of organisms; when the process of self-renewal ends (when autopoiesis stops), we die. I explain this lesson in detail in Difference Maker.

Biomass accumulation

As I explain in Biology Made Real, people in general struggle with the idea of losing mass. When I ask students about how someone loses weight when on a diet, they can’t explain it. They refer, instead, to “exercise”. In my view, too much emphasis in biology is placed on energy; it must be balanced with an understanding of our material nature. In this lesson, I get to reiterate the mass balance rule: whatever enters a system must either leave it or accumulate within it.

Food chains

Many courses jump into food chains without any context, and it becomes “who eats whom”. Following the previous two lessons, I can frame food chains around autopoiesis. The deep meaning is found when exploring what we’re made from. My young students aren’t so sure about this, but in these lessons, we establish that we build ourselves, our cells, from the particles we gain from other organisms. There are just two ways of obtaining particles to build yourself: you either make them or take them.

There is another deep meaning I begin exploring with students in this lesson: complexity and unknowability. I frame the food chain as a simple model. The food web is more complex, but is also a simplified model. Despite this, when I ask them to make predictions about the fate of a food web upon extinction of a member species, they begin to see the myriad of possibilities.

Predator-Prey

This is the first time in the course that my students begin thinking with a more complex stock and flow model. See how I introduce stock and flow models; they are a vital component of my teaching. This is also the first lesson that I introduce a feedback loop. How to teach with stock and flow diagrams was a central topic of my book Difference Maker.

Top Predators

In this lesson I add producers to the model. Students can practice their understanding of the stock and flow model by making sense of the effect of top-predator extinction.

Fungi and nutrient cycling

I explain how I teach this lesson in this post.

Natural Selection

I explain how I teach natural selection in my book Difference Maker.

Cladograms (in the context of vertebrates)

In Biology Made Real, I argued that a principal way of meaning making in biology is through understanding a species’ evolutionary history and relationships. I suggested, therefore, that we should teach cladograms early and then include them often. This is the first lesson on cladograms for my young students. It begins with the small “close family” cladogram in the top-left. Then we explore our extended vertebrate family history.

Endothermy

Endothermy explains many ecological observations and helps us understand ourselves better. It’s also another great opportunity to discuss cell respiration (which should be discussed often).

Allen’s Rule

Teaching Allen’s rule allows students to explain ecological patterns they may come across in their world. It also allows me to introduce the idea of surface area, a concept that returns many times more in my students’ biology education. And, we get to build another stock and flow model. Remember, you can learn how I introduce these here and how to teach with them in my book Difference Maker.