Idea or model
Food chains and webs
Who eats whom in an ecosystem. Energy and nutrients pass from producers to the animals that eat them.
Ecosystem Simulator
Change temperature, rainfall, soil and populations in a plant, herbivore and predator food chain, and watch the whole web respond.
Step 6 of 7LabSimulation
How this step works
- Open the Ecosystem Simulator and work through it at your own pace.
- Come back here and mark the lab as done.
Lab XP is earned once per lab. If another path includes the same lab, finishing it here counts there too.
Concepts you will meet
Process
Energy flow
Energy enters most ecosystems as sunlight and is lost at each step up a food chain, which limits how many levels it can support.
Process
Trophic cascade
Effects that ripple down a food chain, as when predators hold herbivores in check and plants flourish.
Idea or model
Keystone species
A species, often a predator, that strongly shapes its whole community. Robert Paine introduced the term in 1969.
Idea or model
Population dynamics
How population sizes change through births, deaths and interactions such as predation. Mathematical predator-prey models date to the 1920s.
Idea or model
Functional response
How a predator's feeding rate changes with prey density. It often levels off when prey are plentiful.
Idea or model
Paradox of enrichment
In some predator-prey models, adding resources makes population cycles larger and less stable instead of simply raising every population.