THEME: NATURE’S CYCLES - energy in ecosystems
This week, we learned how energy flows throughout an ecosystem. First, we brainstormed wildlife that live in the various ecosystems around the Nature Center. In the forests and fields, we might find rabbits, squirrels, a variety of birds, snakes, deer, raccoons, foxes, and maybe even skunks. In the wetlands, we often find fish, frogs, turtles, waterfowl, snakes, and a variety of insects. We also discussed that some forest and field critters might venture toward the wetlands to drink water. Additionally, within these ecosystems, there are different types of trees, shrubs, grasses, and flowers.
Ms. Paige asked us where the living things in these ecosystems get their energy. We replied, “their food!” So what do these critters eat? If they are carnivores, they eat other organisms. If they are herbivores, they only eat plants. If they eat both, they are omnivores. (Humans fall into this category, though some people might choose to be herbivores!) Then, we got to wondering… where do plants get their food? Short answer: the sun! Long answer: we learned more about photosynthesis, which is the process in which plants create their own food. The green in their leaves is a pigment called chlorophyll, which absorbs sunlight. This stored energy helps plants convert carbon dioxide (from the air) and water into glucose (sugar) for the plants to “eat.” This is also the process in which plants create oxygen for us to breathe! For an activity, we broke into groups and sorted various animal cards into columns based on what they eat.
After some minor adjustments, we had our animals sorted for the next activity. Ms. Paige and Ms. Rachel then taught us about food chains and food webs. Food chains outline who eats what in an ecosystem. Each step of the food chain is called a trophic level. You can picture food chains like a pyramid! At the bottom are producers, or plants, that produce their own food. The second level are primary consumers that eat plants (herbivores). At the next level are secondary consumers that must consume other organisms for their energy (carnivores and omnivores), and then tertiary and quaternary consumers at the following levels. At the top of the food chain are apex predators, which are often large animals that have no known predators (wolves, bears, lions, crocodiles, etc.). This raises the question: where does the energy in a food chain go after it reaches the top of the food chain? Answer: back into the soil via detritivores and decomposers, which eat non-living plant and animal remains. These organisms put nutrients back into the soil for new plants to grow, thus creating a cycle!
Our next activity was to create a food chain with the animal cards, this time with plants and decomposers added in. Some of us took it a step further and created a food web, which shows not just one, but all the different food chains within an ecosystem! Each organism in an ecosystem is part of many different food chains, and no ecosystem is exactly alike. Check out our creations in the photos above. If you would like to learn more about food chains, food webs, and how energy flows throughout an ecosystem, National Geographic is a great place to start.
We also enjoyed a quick hike to the Rock Beach before it was time to head home. We were happy to see some spring sunshine!
