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How are organisms adapted to their environment, and what do they compete for?

The factors organisms compete for, the difference between abiotic and biotic factors, structural, behavioural and functional adaptations, and the meaning of extremophiles.

A focused answer to AQA GCSE Biology 4.7.1, covering what organisms compete for, abiotic and biotic factors, the three types of adaptation, and extremophiles.

Generated by Claude Opus 4.89 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. Competition
  3. Abiotic and biotic factors
  4. Adaptations
  5. Extremophiles
  6. Try this

What this dot point is asking

AQA wants you to state what plants and animals compete for, distinguish abiotic from biotic factors, describe the three types of adaptation, and explain what extremophiles are.

Competition

To survive and reproduce, organisms need a supply of materials from their surroundings and from the other living organisms there. Competition can be interspecific (between different species, for example grey and red squirrels both competing for nuts) or intraspecific (within one species, for example two stags competing for mates). The organisms best able to compete are most likely to survive and reproduce, which links competition to natural selection.

Abiotic and biotic factors

A change in any of these factors can affect how well a community of organisms survives. For example, a fall in light intensity reduces plant growth, which reduces the food available to herbivores; the arrival of a new predator can reduce a prey population sharply. AQA often gives data and asks you to explain a change using one of these factors.

Adaptations

  • Structural: physical features of the body, such as a polar bear's thick fur and small surface area to volume ratio to reduce heat loss, or a cactus's spines (reduced leaves) to cut water loss.
  • Behavioural: the way an organism behaves, such as migrating to a warmer place in winter, or animals being active at night in a desert to avoid the heat.
  • Functional: processes that go on inside the body, such as a desert animal producing very concentrated urine to conserve water, or a bear lowering its metabolism to hibernate.

Extremophiles

Their enzymes are adapted not to denature at temperatures or salt concentrations that would kill most organisms, which is how they survive where almost nothing else can.

Try this

Q1. State two things plants compete for. [2 marks]

  • Cue. Any two of: light, space, water, mineral ions.

Q2. Give one example of a behavioural adaptation. [1 mark]

  • Cue. Migrating to a warmer area in winter (or other valid example).

Exam-style practice questions

Practice questions written in the style of AQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

AQA 20194 marksA polar bear and a camel live in very different environments. Explain how each animal is adapted to survive in its environment, referring to structural and functional adaptations.
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A 4-mark explain question rewards adaptations linked to a clear survival reason.

The polar bear has thick fur and a layer of blubber to insulate it and reduce heat loss, and a large rounded body with a small surface area to volume ratio so it loses less heat (structural). A camel has a thin coat and stores fat in its hump rather than over its body, so it can lose heat and avoid overheating, and it produces very little, concentrated urine and can tolerate water loss (functional).

Markers reward at least one correct adaptation for each animal with the reason it helps the animal survive in cold or hot, dry conditions. Just listing features without linking them to survival limits the marks.

AQA 20213 marksDescribe what is meant by abiotic and biotic factors, and explain how a change in one abiotic factor could affect the size of a population in a community.
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A 3-mark question rewards correct definitions plus a worked example.

Abiotic factors are non-living factors such as light intensity, temperature, moisture and soil pH. Biotic factors are living factors such as food availability, predators, competition and disease. For example, if the temperature falls, plants may grow more slowly and photosynthesise less, so there is less food for primary consumers, whose population would then fall, which would in turn reduce the predators that feed on them.

Markers reward correct definitions of each factor type and a logical chain explaining the effect on a population.

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