Human Impacts On Biodiversity

Question 1

what is biodiversity

Answer 1

the variety of living organisms in an ecosystem

Question 2

what abiotic factor can often affect biodiversity

Answer 2

human interactions

Question 3

what are some of the positive impacts that humans have in biodiversity

Answer 3

• carrying out conservation schemes

- or reforestation

Question 4

how do nitrates find their way into rivers and lakes

Answer 4

• nitrates are put into fields as fertilisers
• if too much is applied and it rains afterwards
• nitrates can find their way into rivers and lakes

Question 5

what is the result of nitrates finding their way into rivers and lakes

Answer 5

eutrophication

Question 6

what is eutrophication

Answer 6

the excess of nutrients in water

Question 7

what is the effect of eutrophication

Answer 7

• it can lead to the death of many of the species present in the water
• reducing the biodiversity of a habitat

Question 8

what is stage 1 of the eutrophication process

Answer 8

• fertilisers enter the water

- adding excess nitrates (more than plants in the water can take in)

Question 9

what is stage 2 of the eutrophication process

Answer 9

• the excess nitrates cause algae to grow fast

- which blocks out the sunlight as they float on the surface

Question 10

what is stage 3 of the eutrophication process

Answer 10

• plants can photosynthesise due to the lack of light

- and start to die and decompose

Question 11

what is stage 4 of the eutrophication process

Answer 11

• with more food available
• microorganisms that feed on decomposing plants increase in numbers
• and use up the oxygen in the water

Question 12

what is stage 5 of the eutrophication process

Answer 12

organisms that need oxygen for aerobic respiration such as fish die

Question 13

how does fish farming contribute to eutrophication

Answer 13

• food is added to the nets of the fish which produce large amounts of waste
• both the food and waste can leak into the open water
• causing eutrophication and the death of wild species

Question 14

what is the effect of fish farms in open water acting as large breeding grounds for parasites

Answer 14

• the parasites can get out of the farm and start infecting animals
• sometimes killing them

Question 15

how does fish farming disrupt the natural food chain

Answer 15

• predators are attracted to the nets

- but they become trapped in them and die as a result

Question 16

why is is bad for farmed fish to escape into the wild

Answer 16

because it causes problems for wild populations of indigenous species

Question 17

why do people prefer to farm fish in large tanks rather than in open water nets

Answer 17

• the farms are low in biodiversity as often only one species is farmed
• tanks are often kept free of plants and predators
• and any parasites or microorganisms are usually killed

Question 18

what is a non-indigenous species

Answer 18

a species that doesnt naturally occur in an area

Question 19

what re the two ways non-indigenous species can be introduced into an area

Answer 19

• intentionally (like for food or hunting)

- or unintentionally (like a stowaway in international cargo)

Question 20

what problems can non-indigenous species cause for indigenous species in terms of competiton

Answer 20

• they compete for resources like food and shelter
• sometimes the non-indigenous are better at competing which decreases the number of indigenous species
• meaning they can eventually die out and have their place taken

Question 21

what is an example of competition being an issue between non-indigenous and indigenous species

Answer 21

• signal crayfish were introduced into the UK for food
• but they prey on and out-compete many indigenous river species
• which reduces biodiversity

Question 22

what problems can non-indigenous species cause for indigenous species in terms of disease

Answer 22

• non-indigenous species can sometimes bring new diseases to a habitat
• these often infect and kill lots of indigenous species
• reducing the habitats biodiversity