The words ecologists use, abiotic and biotic factors, how species in a community depend on each other, and how adaptations suit organisms to where they live.
What you will learn
- Use population, community, habitat and ecosystem correctly
- Sort factors into abiotic and biotic and read a distribution graph
- Predict what happens in a food web when one population falls
- Tell parasitism from mutualism (Edexcel)
- Explain structural, behavioural and functional adaptations
The words of ecology
- A population is all the organisms of one species in an area.
- A community is all the populations of different species in that area.
- A habitat is where an organism lives.
- An ecosystem is a community interacting with the non-living parts of its environment.
Species in a community depend on each other for food, shelter, pollination and seed dispersal: this is interdependence. Take one species away and the others feel it. In a stable community the species and the environment are in balance, so population sizes stay about the same.
- Feeding: water fleas eat algae; sticklebacks eat water fleas
- A disease kills most of the sticklebacks
- Fewer water fleas are eaten, so the water fleas increase
- More water fleas eat more algae, so the algae decrease
Say what changes and why: "less food" or "fewer eaten". The mark is for the reason.
The rest of this lesson and its 12 practice questions are locked.
In this lesson
- The words of ecology
- Parasitism and mutualism (Edexcel and OCR)
- Abiotic and biotic factors
- Adaptations
- Try it: Your first ecology question
12 practice questions, marked as you go; about 20 minutes in all.
Key terms
Population, Community, Habitat, Ecosystem, Interdependence, Stable community, Parasitism, Mutualism, Abiotic, Biotic
In this unit: Ecology
Communities and adaptations, sampling with quadrats, transects and capture-recapture, food chains and the carbon, water and nitrogen cycles, decay, parasitism and mutualism, eutrophication, biodiversity and human impact, biomass transfer and food security.
- Communities, interdependence and adaptations
- Sampling with quadrats, transects and capture-recapture
- Food chains, cycles and decay
- Biodiversity and human impact
- Trophic levels, pyramids and efficiency
- Food security and farming
- Biological control and bioaccumulation
- Fish farming, introduced species and the cycles in depth