B18 Biodiversity and ecosystems

Question 1

What is biodiversity?

Answer 1

A measure of the variety of all the different species of organisms on Earth, or within a particular ecosystem

Question 2

How does high biodiversity help to ensure the the stability of ecosystems?

Answer 2

It reduces the dependence of one species on another for food and shelter

Question 3

How do humans reduce the amount of land available for animals and plants?

Answer 3

By building, quarrying, farming and dumping waste

Question 4

How do humans pollute water ways? (3)

Answer 4

With sewage, fertiliser and toxic chemicals

Question 5

How do humans pollute the air? (2)

Answer 5

Smoke and gases such as sulfur dioxide - which adds to acid rain

Question 6

How is the land being polluted? (5)

Answer 6

Sewage, farming methods, herbicide and pesticides, toxic chemicals from landfill, chemical fertiliser

Question 7

How does high levels of nitrate in the water lead to the death of organisms?

Answer 7

1. High levels of mineral ions stimulate rapid growth of algae and other water plants
2. Competition for light increases and many plants die because they cannot photosynthesise
3. Microorganisms feed on dead plants and the population of microorganisms increases rapidly
4. Respiration by microorganisms depletes the oxygen concentration in the water
5. Most aerobic organisms, like fish, die. Lack of oxygen eventually means the water cannot sustain living organisms

Question 8

Why is sulfur dioxide bad? (3)

Answer 8

Sulfur dioxide dissolves in water in air, forming acid rain.
1. Acid rain kills animals, reducing biodiversity.
2. Acid rain can change a soils pH, which damages roots and releases toxic minerals.
3. Trees can be damaged if leaves are soaked in acid rain for long periods

Question 9

What has deforestation caused? (3)

Answer 9

An increase in the release of carbon dioxide into the atmosphere, reduced the rate at which CO2 is removed from the atmosphere, reduced biodiversity

Question 10

What does the destruction of peat bogs result in?

Answer 10

The release of carbon dioxide into the atmosphere becausew

Question 11

What is peat used as?

Answer 11

Compost

Question 12

Why does peat release carbon dioxide when it is burnt?

Answer 12

Because it contains microorganisms which release carbon dioxide through respiration

Question 13

What may an increase in the Earths temperature cause? (5)

Answer 13

Big changes in the Earths climate, a rise in sea levels, changes in migration patterns, changes in distribution of species, reduce biodiversity

Question 14

What are some environmental changes that affect the distribution of species in an ecosystem?

Answer 14

The availability of water, temperature and the composition of the atmosphere

Question 15

Why are breeding programmes carried out?

Answer 15

To restore endangered species to a sustainable population

Question 16

What are some of the difficulties with breeding programmes? (3)

Answer 16

Many rare animals and plants don’t reproduce easily or fast, need to avoid inbreeding, the habitat needed may be lost

Question 17

Name something that has reduced waste

Answer 17

Taxing landfill

Question 18

How can farmers help increase biodiversity?

Answer 18

By replanting hedgerows and allowing wild plants to grow on edges of fields

Question 19

What is biomass?

Answer 19

The mass of living materials in plants and animals

Question 20

What do trophic levels represent?

Answer 20

An organisms position in a food chain

Question 21

What are apex predators?

Answer 21

Carnivores with no predator

Question 22

What do decomposers do?

Answer 22

Break down dead plant and animal matter by secreting enzymes into environment. Small soluble molecules then diffuse into the microorganism

Question 23

What trophic level has the largest amount of biomass?

Answer 23

Trophic level 1

Question 24

Why does trophic level 2 have less biomass than level 1?

Answer 24

Because the herbivore does not eat all of the plant material and it cannot digest some of what it eats

Question 25

Why is even less biomass transferred to trophic level 3 from level 2?

Answer 25

Because carnivores only eat parts of the herbivore (cannot eat bones etc.)

Question 26

How is biomass lost? (4)

Answer 26

Urine, faeces, providing energy for movement and growth, energy from cellular respiration is transferred by heating up surroundings

Question 27

What is food security?

Answer 27

Having enough food to feed a population

Question 28

What are factors that affect food security? (5)

Answer 28

Increasing birth rates, changing diets in developed countries, new pests and pathogens, environmental changes, the cost of agricultural inputs

Question 29

How can we produce meat more efficiently?

Answer 29

Preventing animals from moving, keeping animals in a warm shed

Question 30

What policies have been put into place to stop fish stocks from declining?

Answer 30

Fishermen: can only remove a quota of fish per year and must use certain sized nets to avoid catching young fish

Question 31

What can fermenters be used to produce?

Answer 31

Drugs

Question 32

What fungus is grown in fermenters to produce mycoprotein?

Answer 32

Fusanumis