Ecosystems
An ecosystem is a community of living things interacting with each other and their physical environment. Every organism in an ecosystem plays a role that keeps the whole system balanced.
Biotic and Abiotic Factors
Biotic factors are the living parts of an ecosystem (plants, animals, fungi, bacteria). Abiotic factors are the non-living parts (water, soil, sunlight, temperature, air).
Both are essential. A pond ecosystem needs water (abiotic), sunlight (abiotic), algae (biotic), fish (biotic), and bacteria (biotic) to function.
Producers, Consumers, Decomposers
| Role | Description | Examples |
|---|---|---|
| Producer | Makes its own food through photosynthesis | Grass, trees, algae, seaweed |
| Primary Consumer (Herbivore) | Eats producers | Rabbit, deer, caterpillar, grasshopper |
| Secondary Consumer (Carnivore/Omnivore) | Eats primary consumers | Fox, frog, snake, small bird |
| Tertiary Consumer | Eats secondary consumers | Hawk, eagle, large sharks |
| Decomposer | Breaks down dead organisms; recycles nutrients | Fungi, bacteria, earthworms |
Food Chains and Food Webs
A food chain shows one path of energy flow: Grass → Rabbit → Fox → Eagle.
A food web shows all the interconnected food chains in an ecosystem. Most animals eat more than one thing, creating a complex web.
Quick Quiz
Test what you just learned. Choose the best answer for each question.