What is an Ecosystem?
An ecosystem is a community of living organisms interacting with each other and with their physical environment. Ecosystems range from a single pond to the entire biosphere, and energy and matter constantly flow through them.
An ecosystem is all the living organisms (biotic factors) in an area interacting with non-living components (abiotic factors) like sunlight, water, and soil, exchanging energy and matter.
- 1↓ProducersPlants and algae capture sunlight via photosynthesis to make food.
- 2↓Primary ConsumersHerbivores eat producers to obtain energy.
- 3↓Secondary ConsumersCarnivores eat primary consumers.
- 4DecomposersBacteria and fungi break down dead matter, returning nutrients to soil.
Step-by-step worked examples
In a grassland ecosystem, producers capture 10,000 kcal of solar energy. Using the 10% energy transfer rule, how much energy reaches primary consumers and secondary consumers?
Producers: 10,000 kcal Primary consumers receive 10% = 1,000 kcal Secondary consumers receive 10% of that = 100 kcal
A pond ecosystem has 200 fish (secondary consumers) supported by 20,000 kg of algae (producers) via the 10% rule. Estimate the biomass of primary consumers (herbivorous fish).
Producers biomass: 20,000 kg Primary consumers ≈ 10% = 2,000 kg Secondary consumers ≈ 10% of that = 200 kg — consistent with 200 fish observed
Classify components of a desert ecosystem: cactus, lizard, sand, sunlight, scorpion.
Biotic (living): cactus, lizard, scorpion Abiotic (non-living): sand, sunlight This split defines the ecosystem's biotic and abiotic factors
Flashcards
Quick quiz
Q1.Which best defines an ecosystem?
Q2.Which of these is an abiotic factor?
Q3.Roughly what percentage of energy transfers to the next trophic level?
Q4.What do decomposers do?
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Common mistakes
Ecosystems only include living things. — Correct: Ecosystems include both biotic (living) and abiotic (non-living) components.
Energy is fully transferred between trophic levels. — Correct: Only about 10% of energy passes to the next level; most is lost as heat.
Decomposers are the same as consumers. — Correct: Decomposers break down dead matter and recycle nutrients; consumers eat living or recently living organisms.
A food chain and food web are the same thing. — Correct: A food chain is one linear energy path; a food web is many interconnected food chains.
FAQ
What is an ecosystem?
An ecosystem is a community of living organisms interacting with each other and with non-living components like water, sunlight, and soil in a given area.
What are examples of ecosystems?
Forests, deserts, coral reefs, grasslands, and ponds are all examples of ecosystems, each with unique biotic and abiotic components.
How does energy flow through an ecosystem?
Energy flows from producers (via photosynthesis) to primary, then secondary consumers, with about 10% transferred at each step, and decomposers recycling nutrients.
What is the difference between a biotic and abiotic factor?
Biotic factors are living things like plants and animals; abiotic factors are non-living things like sunlight, temperature, and soil.