Ecosystems in Balance: Exploring Food Webs and Ecological Interactions

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Ecosystems in Balance: Exploring Food Webs and Ecological Interactions

Learning objective

Learning Objectives

At the end of the lesson, you will understand food webs, identify biotic and abiotic factors, recognise mutualistic relationships, calculate population size, interpret growth curves, and analyse predator-prey cycles.

Understanding Food Webs

A food web illustrates how energy flows through an ecosystem. It consists of multiple interconnected food chains and represents various trophic levels.

Constructing a Food Web

Create a food web with four trophic levels: producers, primary consumers, secondary consumers, and tertiary consumers.

Biotic and Abiotic Factors

Biotic factors are living components like plants and animals. Abiotic factors include non-living elements like water, temperature, and soil.

Mutualistic Relationships

Mutualism is a relationship where both species benefit. Examples: bees and flowers, clownfish and sea anemones.

Population Size Estimation

Use the capture-mark-release-recapture method to estimate population size. Formula: (Number marked in first sample x Total in second sample) / Number recaptured.

Interpreting Growth Curves

Growth curves show population changes over time. Identify phases: lag, exponential, and stationary. Determine limiting factors affecting growth.

Limiting Factors

Limiting factors restrict population growth. Examples: food, water, space, and predation.

Predator-Prey Cycles

Predator-prey cycles show population oscillations. As prey increases, predator populations rise, leading to a decline in prey and, eventually, predators.

Review and Reflect

Review key concepts: food webs, biotic/abiotic factors, mutualism, population estimation, growth curves, and predator-prey cycles.

Write down 3 things you learned in this lesson.

Write down 2 things you want to know more about.

Ask 1 question about something you haven't quite understood yet.