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biology 0610printed 291 · PDF 291
328 pagesrevision 46933
printed 291 · PDF 291
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Notes
Food Supply:
Increases in human food supply are due to:
Use of machinery: more efficient use of time, larger land employed and overall
efficiency
Chemical fertilisers: increase amount of nutrients in soil, plants can grow faster and
better and increased food yield
Insecticides and Herbicides: kill off insects and weeds respectively
Selective breeding: animals and crops which produce a large yield are selectively
bred to produce a large number of organisms with high yield
Monoculture:
● Only one species of crop is grown in a selective area continuously.
● This can lead to lower food prices, increased yield and reduced labour costs.
● However, the crop will be more prone to devastation by natural disaster, pest attack
and increased chance of resistance of pests to the crop. Also reduces biodiversity
Intensive Farming:
● Intensive crop farming involves use of monocultures. Intensive livestock farming is
employed for animals by keeping them in high density and restricting their
movement. High antibiotic doses are given to prevent disease
● It isn’t sustainable. It can cause welfare issues for livestock. If disease does break
out, it spreads quickly and animal waste can contribute significantly to pollution.
Habitat Destruction:
Biodiversity: number of different species that live in an area
Due to human activities (economic, pollution), biodiversity is decreasing in many
areas
Causes of habitat destruction:
Clearing of land for farming and housing, demands are ever increasing and more
land is needed
Extraction of natural resources
Marine pollution
Deforestation: