Friday, June 7, 2019

Modeling Energy Movement Between Trophic Levels


One of my main goals when teaching is to help students understand concepts by them actually interacting with the concept in a hands-on way. I was reading through posts on one of the science teacher Facebook groups that I'm a part of and saw a post about a lab demonstrating energy loss from one trophic level to the next. The lab was part of a set of labs from the Health and Science Pipeline Initiative. Although you need to register to be able to use the curriculum on the website, it is free (my favorite kind). The Medical Biology labs are organized by NGSS Disciplinary Core Ideas for Life Science. Under LS2: Ecosystems: Interactions, Energy, and Dynamics is lab 12 Cycling of Matter and Energy Flow. We just did part "a" of the lab. All parts of the lab look great, but we were short on time. We were able to complete part a in a 40 minute period.


I printed out labels for the cups, representing 5 trophic levels: producers, primary consumers, secondary consumers, tertiary consumers, and quaternary consumers. All cups but the producers have holes in the bottom. We used sidewalk chalk in the parking lot to mark off 10ish foot sections and brought out a couple of water pitchers (representing the energy moving from one trophic level to the next). The lab calls for 500 mL of water per cup, but our cups weren't that big, so we started with 200 mL which worked fine. Next time, we may separate the energy levels by more than 10 feet, since students were getting pretty good at quickly getting from one level to the next without losing much water.


Students had a great time running the leaking cups from one energy level to the next and they had a solid understanding of energy movement and consumption from one tropic level to the next. This one is a keeper.