1. 1
   A logging and agriculture company clears a large area of tropical rainforest in order to create new farmland for growing crops and grazing livestock, and to extract timber for sale. Environmental scientists are monitoring the impact of this deforestation on the local ecosystem.

   (a)

   A large area of tropical rainforest is cleared to create new farmland for growing crops. What is this an example of?

   [1 mark]

   • AConservation
   • BHabitat destruction
   • CNitrogen fixation
   • DSustainable resource management

   (b)

   Besides creating farmland, which other reason listed is a common cause of habitat destruction?

   [1 mark]

   • AExtraction of natural resources, such as timber or minerals
   • BEstablishing new nature reserves
   • CCaptive breeding programmes
   • DSeed banks

   (c)

   Explain two undesirable effects of this deforestation on the local ecosystem and on the wider environment.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A rapidly growing city drains and fills in a large area of wetland habitat to build new housing for its expanding population. Conservationists warn that this wetland previously supported many species of migratory birds and amphibians that will now have to find alternative habitats or face local extinction.

   (a)

   A wetland habitat is drained and filled in to allow the construction of new housing for a growing human population. What is the main cause of habitat destruction described here?

   [1 mark]

   • AMarine pollution
   • BFreshwater pollution
   • CExtraction of natural resources
   • DIncreased area needed for housing

   (b)

   Conservationists warn that species of migratory birds and amphibians that previously used the wetland will now have to find alternative habitats. Which term describes the total number of different species that lived in this area before it was destroyed?

   [1 mark]

   • ATrophic level
   • BPopulation
   • CBiodiversity
   • DGenotype

   (c)

   Explain how destroying this wetland habitat could alter existing food webs and food chains in the local area, and explain why this is described as a negative impact of human activity on the ecosystem.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A mining company clears a large area of forest to extract valuable mineral ore from the ground beneath, while in a nearby coastal region, untreated sewage and agricultural runoff are increasingly polluting a river estuary that supports a rich diversity of fish and shellfish species.

   (a)

   Describe three separate reasons, including this one, why habitats are commonly destroyed by human activity.

   [3 marks]

   (b)

   In the nearby coastal region, untreated sewage and agricultural runoff are increasingly polluting a river estuary. Explain how freshwater pollution such as this can contribute to habitat destruction, referring to the effects on the organisms living in the estuary.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   An international environmental organisation is comparing two major examples of habitat destruction caused by human activity: large-scale deforestation of tropical rainforest for palm oil plantations, and severe pollution of a major river system by untreated sewage and industrial waste, which is destroying downstream wetland habitats.

   (a)

   A large area of tropical rainforest is being cleared for palm oil plantations, a major cause of deforestation in many tropical countries. Explain fully the undesirable effects of this deforestation, referring to biodiversity, extinction, soil, flooding and atmospheric carbon dioxide, and explain how these effects are interconnected.

   [6 marks]

   (b)

   A major river system downstream of several large cities and factories is being severely polluted by untreated sewage and industrial waste, destroying wetland habitats along its course. Explain fully how this pollution leads to the destruction of these wetland habitats, and evaluate how the effects of this pollution-driven habitat destruction compare with the effects of the deforestation described in your previous answer.

   [6 marks]

   Total for question 4: 12 marks

End of questions