Human Influences on Ecosystems Details

Question 1

Ways with which humans have increased food production

Answer 1

-Agricultural machinery(to use larger areas of land and improve efficiency)
-Chemical fertilisers(to improve yields)
-Insecticides(to improve quality and yield)
-Herbicides(to reduce competition with weeds)
-Selective breeding(to improve production by crop plants and livestock)

Question 2

Advantages of large-scale monocultures of crop plants

Answer 2

-Yields higher amounts of certain crops
-Improves efficiency
-Easier to manage
-More profitable

Question 3

Disadvantages of large-scale monocultures of crop plants

Answer 3

-Decreases soil quality
-Uses more water for irrigation
-Adversely affects the natural environment
-Higher amount of pests/pesticides
-Less biodiversity
-Crops more vulnerable to disease

Question 4

Advantages of intensive livestock production

Answer 4

-Cheaper
-Less land needed
-Less manual
-Greater efficiency
-Higher yield

Question 5

Disadvantages of intensive livestock production

Answer 5

-Overgrazing can lead to soil erosion
-Reduction in biodiversity
-Cruel to animals(perceived)
-Quicker spread of disease
-Disposal of waste pollutes the environment

Question 6

Effects of deforestation

Answer 6

-Less biodiversity
-Extinction
-Loss of soil
-Flooding
-Increase of carbon dioxide in the atmosphere

Question 7

Effects of untreated sewage and excess fertiliser on aquatic ecosystems

Answer 7

-Less biodiversity
-Extinction
-Loss of habitat
-Eutrophication
-Water pollution
-Spread of disease

Question 8

Effects of non-biodegradable plastics in aquatic and terrestrial ecosystems

Answer 8

-Water pollution
-Land pollution
-Spread of disease
-Damage to living organisms
-Depletion of soil fertility

Question 9

Causes of habitat destruction

Answer 9

-Oil spills
-Eutrophication
-Logging
-Mining
-Freshwater/Marine pollution
-Livestock production
-Housing
-Crop plant production

Question 10

Effects of pollution of the air by methane and carbon dioxide

Answer 10

-Enhanced greenhouse effect
-Climate change

Question 11

Process of eutrophication

Answer 11

-Increases availability of nitrate and other ions
-Increased growth of producers(eg. algae)
-Increased decomposition after death of producers
-Increased aerobic respiration by decomposers
-Reduction in dissolved oxygen
-Death of organisms requiring dissolved oxygen in water

Question 12

Causes of the extinction/endangerment of organisms

Answer 12

-Climate change
-Habitat destruction
-Hunting
-Overharvesting
-Pollution
-Introduction of invasive species

Question 13

How endangered species can be conserved

Answer 13

-Monitoring/Protecting species and habitats
-Education
-Captive breeding programmes
-Seed banks

Question 14

How forests can be conserved

Answer 14

-Education
-Protected areas
-Quotas
-Replanting/Afforestation

Question 15

How fish stocks can be conserved

Answer 15

-Education
-Protected areas
-Closed seasons
-Controlled net types and mesh size
-Quotas and monitoring

Question 16

Reasons for conservation programmes

Answer 16

-Maintaining/Increasing biodiversity
-Reducing extinction
-Protecting vulnerable ecosystems
-Maintaining ecosystem functions

Question 17

Process of artificial insemination

Answer 17

-Woman’s cycle is monitored
-On day 14, sperm is inserted into the uterus

Question 18

Process of in vitro fertilisation

Answer 18

-Woman is given hormones to increase egg count
-Eggs are taken and placed into a dish
-Sperm is added to a dish
-Fertilisation occurs
-The fertilised eggs develop into embryos and are implanted into the uterus at 8 cell stage(stage when the embryos are 8 cells)

Question 19

Impacts of the decline of the population of a species

Answer 19

-Reduced genetic variation
-Increased susceptibility to diseases
-Decreased adaptability
-Potential health issues due to inbreeding
-Greater risk of extinction
-Increased susceptibility to environmental change