Niche and adaptationEdexcel International A Level Biology: Subtopic test

1. 1
   A tropical rainforest contains many species of tree frog. Several species live in the same area of forest, but each feeds at a different height in the trees, at different times of the night and on different kinds of insect.

   (a)

   Which statement best describes the niche of a species?

   [1 mark]

   • AThe place where the species lives, such as the forest canopy
   • BThe number of individuals of the species in the forest
   • CThe role of the species in its community, including its feeding, its interactions with other species and the conditions it tolerates
   • DThe adaptations that the species has inherited from its ancestors

   (b)

   Which feature of the frogs is a behavioural adaptation?

   [1 mark]

   • AFeeding at night, when their insect prey is most active
   • BSticky pads on the toes that grip leaves
   • CA thin, moist skin that absorbs oxygen
   • DA tongue with a structure that traps insects

   (c)

   Explain why several species of tree frog can live in the same area of forest without competing strongly.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   The kangaroo rat lives in a hot desert and never drinks. It produces very concentrated urine, spends the day in a cool, humid burrow and searches for seeds at night. The Namib desert beetle stands on a dune crest in the early morning with its body tilted head-downwards, so that fog condenses on its back and runs down to its mouthparts.

   (a)

   Which feature of the kangaroo rat is a physiological adaptation?

   [1 mark]

   • AStaying in a burrow during the day
   • BHaving long hind legs for hopping
   • CHaving large eyes for seeing in the dark
   • DProducing very concentrated urine

   (b)

   The beetle tilts its body head-downwards on the dune crest. What type of adaptation is this?

   [1 mark]

   • AAnatomical, because it depends on the shape of the body
   • BBehavioural, because it is an action that the beetle carries out
   • CPhysiological, because it involves water
   • DNot an adaptation, because it is not a structural feature

   (c)

   Explain how spending the day in a burrow and searching for food at night reduces water loss in the kangaroo rat.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   The fennec fox lives in the Sahara and has very large ears. The Arctic fox lives in northern Canada, where winter temperatures fall to −40 °C, and has small ears and a thick coat. When resting, the Arctic fox curls up with its tail over its nose, and it constricts the blood vessels in the skin of its legs and paws.

   (a)

   Explain how the difference in ear size is an anatomical adaptation in each fox.

   [3 marks]

   (b)

   Identify one behavioural adaptation and one physiological adaptation of the Arctic fox from the information given. Explain how each helps the fox to survive the cold.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   On a coastal mudflat three species of wading bird feed at low tide. The curlew has a long, curved bill, walks slowly and probes deep into the mud for lugworms. The dunlin has a short, straight bill and runs along pecking small invertebrates from the surface. The redshank has a medium-length bill and feeds mainly on shrimps and snails in the shallow water at the edge. All three species have salt glands near the eyes.

   (a)

   Explain how adaptations allow the three species of wading bird to coexist on the same mudflat. Refer to the concept of a niche in your answer.

   [6 marks]

   (b)

   A new species of wader arrives on the mudflat. It has a medium-length bill, feeds on shrimps and snails in shallow water at the water's edge and feeds at the same times as the redshank. Evaluate whether the new species is likely to become established alongside the redshank.

   [6 marks]

   Total for question 4: 12 marks

End of questions