Sustainability and conservation of speciesEdexcel A-Level Biology A: Subtopic test

1. 1
   A packaging company is developing carrier bags made from a bioplastic produced from the starch in maize grain. The company wants to replace bags made from polythene, which is made from crude oil, and it wants to claim that the new bags are more sustainable.

   (a)

   Which statement best explains why a bioplastic made from maize starch is more sustainable than polythene?

   [1 mark]

   • AThe raw material is renewable because the crop can be regrown, whereas crude oil is finite
   • BGrowing maize needs no land, water or fertiliser
   • CStarch bioplastic is broken down in any conditions, including in a sealed landfill
   • DMaking a bioplastic needs no energy

   (b)

   Starch is a polymer of which monomer?

   [1 mark]

   • AFructose
   • Bα-glucose
   • Cβ-glucose
   • DAmino acids

   (c)

   Explain why using a plant-based plastic instead of a plastic from crude oil may reduce the net release of carbon dioxide into the atmosphere.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A seed bank holds the seeds of endangered wild plant species. The seeds are dried to a low moisture content, sealed in containers and stored at -20 °C. Staff test samples of each batch for germination every ten years.

   (a)

   What is the main reason for drying the seeds before they are stored?

   [1 mark]

   • ATo kill the embryo so it cannot be damaged
   • BTo make the seeds larger
   • CTo reduce metabolic activity and stop germination and fungal growth
   • DTo break the dormancy of the seeds

   (b)

   Which seeds could not be conserved in this seed bank?

   [1 mark]

   • AVery small seeds
   • BSeeds with a hard seed coat
   • CSeeds from an annual plant
   • DSeeds that die when dried or frozen

   (c)

   Explain how the seed bank helps to conserve the genetic diversity of an endangered species.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A zoo manages 40 captive individuals of an endangered mammal species. Each animal's parentage is recorded in a studbook, and the zoo exchanges animals with other zoos so that breeding pairs are chosen carefully. The long-term aim is to release some offspring into a protected reserve.

   (a)

   Explain why the zoo uses a studbook and exchanges animals with other zoos when planning its breeding.

   [3 marks]

   (b)

   Describe how a zoo can contribute to conservation through research, education and reintroduction.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A government agency in a tropical country has a limited budget to protect species that are threatened by the clearance of forest for farming. It is deciding how much to spend on a seed bank for threatened plants and how much on a zoo breeding programme for threatened animals.

   (a)

   Evaluate the use of a seed bank to conserve threatened plant species.

   [6 marks]

   (b)

   Evaluate the use of captive breeding and reintroduction programmes in zoos to conserve threatened animal species.

   [6 marks]

   Total for question 4: 12 marks

End of questions