KS3 · Biology

Ecosystems and habitats

Tip up a plant pot and you're looking at a habitat. So is the whole ocean. What could those two possibly have in common?

Biology · Habitats

Living or non-living? Sort the factors

Pick a card, then choose its column. Is it a living (biotic) factor or a non-living (abiotic) factor?

Still to sort

Biotic — living factors (0)

Living things that affect other living things, including what organisms do to each other.

Where the line is: Ask yourself: is this living things acting on other living things? Feeding, competing and reproducing all go here — and so does disease.

Abiotic — non-living factors (0)

Non-living things that affect living things: characteristics of the habitat you can measure.

Where the line is: Ask yourself: is this a non-living condition of the place that you could measure, like how warm or how bright it is? Then it's abiotic.

10 of 10 still to sort.

Every one of these factors affects the organisms living in a habitat. Your job is to decide which side each one belongs on.

Watch out: Disease is a biotic factor. It isn't an organism you can point at, so it's easy to drop it in the non-living column — don't.

Biology · Habitats

From the ocean to under a plant pot

Put these habitats in order of size, biggest first

1 · Largest4 · Smallest

  1. Under a plant pot

  2. The ocean

  3. Inside a fallen tree

  4. A lake

Watch out: Don't judge a habitat by its size. Judge it by the three things it provides.

Predict, then check

You've just met the ocean and a lake. Both are habitats, and both are full of water.

Do an ocean and a lake have the same non-living (abiotic) parts?

Biology · Ecosystems

Population, community, ecosystem

You've probably heard 'population' and 'community' used about people — the population of a town, the local community. Scientists use both words more exactly, and about any kind of organism. Picture a scientist studying a lake.

Which of these is closest to what you think right now?
How sure are you?

Adaptations and extinction

?

Reason it through

Why can a big change in a habitat lead to a species becoming extinct?

Link 1 of 4

First link · your turn

Start with the organism. What makes it suited to living in its habitat?

2
Locked — reveal the link above first
3
Locked — reveal the link above first
4
Locked — reveal the link above first

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

From the whole ocean to the space under a plant pot: what makes a place a home, and what shapes life there.

What you need to know

  • A habitat is where organisms live. To count as a habitat, a place must provide food, shelter and a place to reproduce.
  • Biotic factors are living things that affect other living things. Abiotic factors are non-living, measurable conditions that affect living things.
  • A population is the organisms of one type in an area. A community is the interacting populations of different organisms in a place.
  • Adaptations are inherited features that suit organisms to their habitat.

The big picture

A habitat is where organisms live, and every habitat — from the ocean, the largest on Earth, to a microhabitat under a plant pot — must provide food, shelter and a place to reproduce. Each habitat has biotic factors (living things affecting other living things, including disease) and abiotic factors (measurable non-living conditions such as temperature and light intensity). Organisms of one type in an area form a population; the interacting populations of different organisms form a community; add the physical environment and you have an ecosystem. Adaptations suit organisms to their habitat, but because they are inherited, too much environmental change may lead to extinction.

Key points

1An ecosystem is made of living organisms, which interact and depend on each other, plus their physical environment — the non-living parts such as rocks and soil.
2Habitats range in size from the ocean, the largest habitat on Earth, to microhabitats such as under plant pots or inside fallen trees.
3Biotic factors include organisms feeding on each other, competing for food or shelter, and reproduction. Disease is a biotic factor too.
4Abiotic factors include soil type, light intensity, water availability or humidity, temperature and oxygen level. They differ between habitats: the ocean has salt water, while rivers, streams and lakes have fresh water.
5Adaptations help organisms find and eat food, avoid predators, move, shelter and keep warm or cool. Because they are inherited, a changing environment may make survival harder, and too much change may lead to extinction.

Worked example

Problem

A scientist visits a stream. She measures the temperature of the water, the light intensity and the oxygen level. Then she counts every organism of one type living in one stretch of the stream. Which of her measurements are abiotic factors, and what is her count called?

⚠ Watch out

Using the everyday meaning of 'population' — the number of people in a town. In ecology, a population is the number of organisms of one type living in a specific area, and it can be any type of organism.

🧠

Memory hook

Food, shelter, a place to reproduce: every habitat, from the ocean to under a plant pot, passes that same three-part test. And for the factors, remember that 'bio' means life and the 'a' at the front of abiotic means 'not' — so abiotic means not living.

✓

Check yourself

Cover the page: name two biotic and two abiotic factors, then explain how a population is different from a community.

Flashcards

(13)
What is an ecosystem made of?
Living organisms, which interact and depend on each other, plus their physical environment (the non-living parts such as rocks and soil).
In ecology, what is a population?
The number of organisms of one type that live in a specific area.
In ecology, what is a community?
The interacting populations of different living organisms in a place.
What is a habitat?
The place where an organism lives. It provides the conditions the organism needs to survive.
What three things must a place provide to be a habitat?
Food, shelter and a place to reproduce.
What is the largest habitat on Earth, and what is a microhabitat?
The ocean is the largest. A microhabitat is a very small habitat, such as under a plant pot or inside a fallen tree.
What is a biotic factor? Give two examples.
A living thing that affects other living things — for example organisms feeding on each other, competing for food or shelter, or reproducing.
Is disease a biotic or an abiotic factor?
Biotic.
What is an abiotic factor? Give three examples.
A non-living, measurable characteristic that affects living things — for example soil type, light intensity, water availability or humidity, temperature, oxygen level.
How do the non-living parts of an ocean and a lake differ?
The ocean has salt water; a lake (like a river or stream) has fresh water.
What is an adaptation, and what can it help an organism do?
A special feature that suits an organism to survive in its habitat — for example to find and eat food, avoid predators, move, shelter, or keep warm or cool.
Where do an organism's adaptations come from?
They are inherited from its parents.
What may happen to organisms if their environment changes too much?
They may become extinct.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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How this lesson was checked. This KS3 Biologylesson was published through Lightbulb Learning's human-designed editorial process — the educational standards, accuracy rules and publication checks it must pass were authored and approved by Philip Halpin. It passed subject-specific assessment, automated educational checks and technical publication verification before going live (publication checks completed 29 September 2026). Published pages are monitored, human spot-checking is ongoing across the lesson library, and anything found wrong is corrected or withdrawn. How our lessons are made and checked. Spotted a mistake? Email hello@lightbulblearning.co and we'll review it.