International A Level Biology / Biodiversity and conservation
Niches and adaptations
Edexcel International A Level Biology (YBI11), chapter 12: Biodiversity and conservation, specification point 4.19. Free lesson.
Read the revision notes · International A Level Biology past papers
A niche is a species’ role in its habitat, while an adaptation is a feature that helps it survive and reproduce there. Identifying the type of adaptation and explaining how it helps can earn important marks.
What a niche means
A niche is the role of a species in its habitat. It includes how the species interacts with other organisms and the conditions it needs to survive. The habitat is simply where it lives, so the two terms do not mean the same thing. Interactions include what the species eats and what eats it. Two species cannot share one niche in a habitat for long because they compete, and one will eventually win.
How adaptations are grouped
An adaptation is a feature that helps an organism survive and reproduce in its niche. Adaptations come about through natural selection. To classify one, ask whether it is something the organism does, a body structure, or a process inside the body. Behavioural adaptations are what an organism does. Kangaroo rats stay in burrows during the hot day. Anatomical adaptations are features of body structure. Snow leopards have thick fur. Physiological adaptations are processes inside the body. Kangaroo rats’ kidneys make very concentrated urine.
How snow leopard features suit its niche
Snow leopards hunt wild sheep and goats in cold, steep, rocky mountains. Their body features help them cope with the cold and move or hide while hunting. These are all anatomical adaptations because they are parts of the body. Thick fur insulates the body, reducing heat loss in freezing air. Small, rounded ears have a small surface area, so less heat is lost from them. Wide, furry paws spread the leopard’s weight on snow and help it grip rock. A long, thick tail helps it balance on steep rock and can wrap round its body for warmth. A grey coat with dark spots…
How kangaroo rat features suit its niche
Kangaroo rats live in hot, dry deserts, eat dry seeds and are hunted by snakes and owls. Their adaptations help them save water or escape predators. Behavioural: staying in a cool burrow by day and feeding at night reduces water loss by evaporation. Physiological: kidneys make very concentrated urine, so very little water is lost in urine. Physiological: water released when food in the seeds respires helps the rat survive without drinking. Anatomical: long, strong back legs let it leap away from predators such as snakes.
Explain the mechanism, not just the feature
Naming a feature or its type is not enough. Explain exactly how it helps the organism survive in its niche. A vague effect may not show the mechanism needed for the mark. “Thick fur keeps it warm” is too vague. “Thick fur insulates it, reducing heat loss” explains how the feature works. For emperor penguins, huddling is behavioural because it is something they do. Each penguin has less surface exposed to the cold wind, so it loses less heat and uses less stored energy.