the place where an organism lives. The role is the niche.

Which is an abiotic component?

salinity. Abiotic means non-living.

What is an apex predator?

a predator at the top of its food chain. Nothing hunts it.

the transfer of pollen from an anther to a stigma. It comes before fertilisation.

Two species of bird eat the same seeds. What is this interaction?

competition. Both need the same limited resource.

Why does an invasive species often increase rapidly?

it has no natural predators in its new home. Nothing keeps its numbers in check.

Ecosystems and how organisms interact · Cambridge IGCSE Environmental Management

In plain words

Nothing lives alone. A pond, a forest or a patch of desert is a web of living things tied to each other and to the water, light and warmth around them. Ecology has a small set of exact words for the parts of that web, and the exam asks for them by name.

10 things to know

An ecosystem is all the living things in an area together with their non-living surroundings, and the ways they affect each other.
A habitat is the place where an organism lives. A species is a group of organisms that can breed together to produce fertile offspring.
A population is all the organisms of one species living in an area. A community is all the populations of different species living in the same area.
A niche is the role of a species in its ecosystem: where it lives, what it eats and how it affects other species.
A predator is an animal that hunts and eats other animals. Its prey is the animal it eats. An apex predator is at the top of its food chain and has no predators of its own.
Biotic components are the living ones: producers, primary, secondary and tertiary consumers, and decomposers.
Abiotic components are the non-living ones: temperature, water, oxygen, carbon dioxide, salinity, light and pH.
A native species lives naturally in an area. An invasive species has been brought in from elsewhere and spreads, harming native species. It often has no predators in its new home.
Competition happens when organisms need the same limited resource, such as food, light, water or space. Predation is one animal feeding on another.
Pollination is the transfer of pollen from an anther to a stigma. In insect pollination an insect carries the pollen. In wind pollination the wind carries it. Pollination leads to fertilisation, followed by the formation of seeds and fruit.

Worked example

Rabbits are brought to an island that has never had them. There is grass, and there are no predators. Predict what happens and name the type of species.

With food and no predators, the rabbit population grows very fast.
The rabbits compete with native animals for grass, and overgraze it.
Native species lose food and habitat and decline. The rabbit is an invasive species.

Tips and tricks

Population is one species. Community is all the species. Ecosystem is the community together with the abiotic surroundings. Each term adds one thing to the one before.
A habitat is an address. A niche is a job. "Lives in the forest" is the habitat, and "eats insects on tree bark" is part of the niche.

6 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Ecosystems and how organisms interact: 6 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

What is a habitat?
- the role of a species in its ecosystem
- the place where an organism lives (the answer)
- all the species in an area
- a group of organisms that can breed together
The role is the niche.
Which is an abiotic component?
- a decomposer
- a producer
- a predator
- salinity (the answer)
Abiotic means non-living.
What is an apex predator?
- a predator that eats only plants
- the smallest predator in a food chain
- a predator that is hunted by many others
- a predator at the top of its food chain (the answer)
Nothing hunts it.
What is pollination?
- the transfer of pollen from an anther to a stigma (the answer)
- the growth of a seed into a plant
- the scattering of seeds
- the making of glucose in leaves
It comes before fertilisation.
Two species of bird eat the same seeds. What is this interaction?
- predation
- pollination
- competition (the answer)
- decomposition
Both need the same limited resource.
Why does an invasive species often increase rapidly?Stretch
- it reproduces more slowly than native species
- it has no natural predators in its new home (the answer)
- it needs no food
- it is always larger than native species
Nothing keeps its numbers in check.

6 questions

Tap an answer and you’ll see straight away whether it’s right, and why.

Worksheet

3 questions, 8 marks. Write your answers on paper, then check them.

Ecosystems and how organisms interact

Cambridge IGCSE Environmental Management 0680 · 8 marks · papermunch.org

Name ______________________________ Date ______________

Define the terms population and community.[2]
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A population is all the organisms of one species living in an area. A community is all the populations of different species living in the same area.
I got this one
State three abiotic components of an ecosystem.[3]
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Any three: temperature; water; oxygen; carbon dioxide; salinity; light; pH.
I got this one
Describe pollination and what it leads to.[3]
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Pollen is transferred from an anther to a stigma, by an insect or by the wind. This leads to fertilisation. Seeds and fruit then form.
I got this one

Answers: Ecosystems and how organisms interact

1. A population is all the organisms of one species living in an area. A community is all the populations of different species living in the same area.
2. Any three: temperature; water; oxygen; carbon dioxide; salinity; light; pH.
3. Pollen is transferred from an anther to a stigma, by an insect or by the wind. This leads to fertilisation. Seeds and fruit then form.