20.Human influences on Ecosystems

Question 1

Describe how humans have increased food production using:

a) Agricultural machinery

Answer 1

Famers can cultivate a much greater area of land and in a much shorter time-Improved efficiency

Question 2

b)Agricultural chemicals

3 details

Answer 2

• Chemical fertilisers: add more mineral ions to soils that do not contain enough of them-Increased crop quality
• Insecticides: kill insect pests that might reduce yields or make crop look less appealing to buyers.
  * Herbicides: kill weeds which compete with crop plants and reduce their growth

Question 3

c)Selective Breeding

Answer 3

-Animals and crop plants which produce a large yield are selectively bred to produce breeds that reliably produce high yields

Question 4

What is a Monoculture?

Answer 4

An area of ground covered by a single crop with almost no other species present.

Question 5

What are the advantages of monocultures?

Answer 5

• Faster and more efficient cultivation as there are large uninterrupted areas of land
• Large areas of the same crop can all be treated with the same herbandpesticides
• They produce large quantities of seeds, fruit, etc all in uniform size and quality-Easier and more profitable market is to sell

Question 6

What are the disadvantages of monocultures?

Answer 6

• Reduction of biodiversity as only one species is present.
• Increase in pests
• Reduction in soil fertility as all the plants need the exact same nutrients-Soil Depletion
  *

Question 7

What is Intensive livestock production?

Answer 7

-Practice where* large numbers of livestock *are kept in an area that would not normally be able to support more than a very small number.

Question 8

Advantages of ILP

Answer 8

• Less land is required to produce large amounts of food
• Food can be produced all year round in controlled environments
• The cost of production is lower
• therefore food can be sold at cheaper prices
• There is a lower requirement for labour to produce the food

Question 9

Disadvantages of ILP

Answer 9

• Welfare issues due to crowded conditions
• Diseases spread easily
• The waste from the units can pollute land and waterways.
• Large quantities of raw materials like water are needed
• Energy costs

Question 10

Four details

Habitats are destroyed when we:

Answer 10

• Cut down vegetation for growing crops,farming livestock, building houses and factories, and for building factories.
• Mine for natural resources,building material and fossil fuels
• We add pollutants to water, which kills aquatic plants and animals.
• Remove species from them-Damage food chains/webs

Question 11

Deforestation is the mass cutting down of trees

What are the effects of Deforestation?

Answer 11

• Reduction of **Biodiversity **as rainforests are cut down
• Soil erosion since soil under trees is exposed to rainfall
• Flooding as soil washed into rivers causes them to overflow.
• Extinction as the habitats of animals are destroyed.
• Less rainfall as *less transpiration occurs
• Increase of carbon dioxide in the atmosphere-Less photosynthesis