Biodiversity and conservationEdexcel A-Level Biology B: Subtopic test

1. 1
   Students sampled ground-dwelling invertebrates in Woodland A. They found six species and recorded the number of individuals of each: 12, 6, 4, 3, 3 and 2. They used the index of diversity, D = N(N-1) / sum of n(n-1), where N is the total number of individuals and n is the number of individuals of each species.

   (a)

   What is the index of diversity D for Woodland A, to two significant figures?

   [1 mark]

   • A4.1
   • B4.6
   • C0.22
   • D6.0

   (b)

   Which statement about a habitat with a high value of D is correct?

   [1 mark]

   • AIt has many species and the individuals are spread fairly evenly between them
   • BIt is dominated by one very abundant species
   • CIt contains very few species
   • DIts species have low genetic diversity

   (c)

   Woodland B also has six species and 30 individuals, but 22 of the individuals belong to one species. Without calculating, state whether D for Woodland B is higher or lower than for Woodland A and explain why.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Cheetahs went through a population bottleneck in the past and now all living cheetahs are very closely related. Studies show very little variation in their alleles. Many males produce abnormal sperm, many cubs die young, and conservationists fear that a single new disease could spread through almost the whole population.

   (a)

   Which measurement is used to assess genetic diversity within the cheetah species?

   [1 mark]

   • AThe number of different species in the habitat
   • BThe total number of cheetahs alive
   • CAn index of diversity calculated from the abundance of each species
   • DThe number of different alleles of genes in the cheetah gene pool

   (b)

   Why does low genetic diversity make the cheetah population vulnerable?

   [1 mark]

   • ACheetahs can no longer undergo mutation
   • BIt increases the number of species in the area
   • CFew alleles mean it is unlikely that any individuals carry alleles that give resistance to a new disease
   • DEvery cheetah now carries a different set of alleles

   (c)

   Zoos run a captive breeding programme for cheetahs. Suggest how the programme could maintain as much genetic diversity as possible.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A tropical rainforest on an island contains thousands of species. One plant species in it, the rosy periwinkle, is the source of vincristine, a drug used to treat leukaemia. The forest is used by local people for timber and food, absorbs large amounts of carbon dioxide, regulates local rainfall and attracts tourists. The government is considering clearing part of the forest to grow oil palms.

   (a)

   Explain the economic reasons for maintaining the biodiversity of the rainforest.

   [3 marks]

   (b)

   Explain two ethical reasons for maintaining biodiversity, and suggest why these may conflict with the needs of local people.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A conservation charity is planning to protect a critically endangered rhinoceros species with fewer than 80 individuals left in the wild, and also a rare plant that grows only in the same forest. The forest is being cleared by loggers and the rhinoceros is poached for its horn. The charity can support zoo breeding programmes, a seed bank, a protected reserve, or a combination.

   (a)

   Evaluate the use of ex-situ conservation methods, such as zoo breeding programmes and seed banks, for the rhinoceros and the rare plant.

   [6 marks]

   (b)

   Evaluate in-situ conservation, such as a protected reserve, and justify which approach the charity should give priority to.

   [6 marks]

   Total for question 4: 12 marks

End of questions