10.3

Question 1

“Explain how agriculture has impacted species diversity (SD)” (3)

Answer 1

(1) the few species possessing desirable qualities are selected for and bred.
(2) other species are excluded by culling or using pesticides
(3) growth of many individuals of a few species = low SD

Question 2

“Why is there a reduction in SD when a forest is replaced by grassland for grazing sheep or cattle?” (6)

Answer 2

(1) forests have many layers…
(2) and have many habitats with many different species
(3) so they have a higher SD
(4) grasslands have a single layer…
(5) and have fewer habitatsand have less species
(6) so they have a lower SD

Question 3

“Why does the loss of tropical rainforest have a greater effect on global biodiversity than the loss of any other ecosystem?” (1)

Answer 3

(1) because tropical rainforests have a greater number & variety of species than any other ecosystem

Question 4

“A forest was cleared to make more land available for agriculture. After the forest was cleared, the SD of insects in the area decreased. Why?” (3)

Answer 4

(1) there’s a decrease in the variety of plants
(2) so there are fewer habitats
(3) so there’s a decrease in the variety of food sources