Ecosystems: Food Chains, Food Webs and Energy Flow

What Is an Ecosystem?

An ecosystem is a community of living organisms (plants, animals, microbes) interacting with each other and with their non-living environment (soil, water, air, sunlight) within a given area.

Components of an Ecosystem

• Biotic components: all living things - producers, consumers, decomposers.
• Abiotic components: non-living factors such as temperature, light, water and soil.

Food Chains and Food Webs

A food chain shows a single pathway of energy flow, e.g. Grass → Grasshopper → Frog → Snake → Hawk. A food web is a network of interconnected food chains showing more realistic feeding relationships in a habitat.

Trophic Levels

• Producers - green plants that make their own food.
• Primary consumers - herbivores that eat producers.
• Secondary/tertiary consumers - carnivores that eat other animals.
• Decomposers - bacteria and fungi that break down dead matter, recycling nutrients.

Interrelationships

Organisms interact through competition (for food, space), predation (predator-prey), symbiosis (mutual benefit), and parasitism (one benefits, one is harmed). These relationships keep the ecosystem balanced.