UNIT OVERVIEW

This revision guide covers Population Ecology — how groups of organisms grow, interact, and change over time. You will revise the factors that control population size, how species interact with each other, and how human populations affect the environment.

What you should be able to do after this revision:

• Explain what makes populations grow or shrink
• Draw and interpret population growth curves
• Describe different types of species interactions (predation, competition, parasitism, mutualism, commensalism)
• Analyse human population trends using population pyramids
• Calculate population estimates using the mark-recapture method and quadrat sampling

What you need to know already:

• Grade 10: Biosphere, biomes, and ecosystems
• Grade 10: Energy flow in food chains and food webs
• Term 1 & 2: Animal biodiversity and adaptations

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