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Year 11 TRIPLE GCSE AQA Biology + Practicals > B18 - Biodiversity and Ecosystems > Flashcards

B18 - Biodiversity and Ecosystems Flashcards

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1
Q

What is biodiversity?

A

The variety of the different species on earth or within an ecosystem.

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2
Q

What is the importance of biodiversity?

A

To maintain the stability of an ecosystem.

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3
Q

How does biodiversity ensure the stability of an ecosystem?

A

It reduces the dependence on particular species for resources eg. food and shelter, so that even if one species is removed other
species can still survive.

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4
Q

Why have humans’ consumption of resources and waste production increased?

A

● Rapid rise in human population
● Increase in standard of living

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5
Q

Where does pollution occur?

A

● Air
● Land
● Water

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6
Q

State an example of water pollutants.

A

● Sewage
● Fertiliser
● Chemicals

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7
Q

How does eutrophication occur?

A
  • Fertiliser from farms pollute the water, causing excessive algae growth, depleting the oxygen in the water, causing other plants and animals to die.
  • Dead plants are decomposed by bacteria and the oxygen level decreases further.
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8
Q

State an example of air pollutants.

A

● Smoke
● Acidic gases

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9
Q

State an example of land pollutants.

A

● Landfill waste
● Chemicals

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10
Q

Which human activities reduce the land available for animals and plants?

A

● Building
● Farming
● Quarrying
● Disposing of waste

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11
Q

Why have peat bogs been destroyed?

A

To produce compost to increase food production.

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12
Q

Why does the destruction of peat bogs greatly contribute to the greenhouse effect?

A

Peat bogs are stores of carbon (carbon sinks) and burning them releases a large volume of carbon dioxide into the atmosphere.

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13
Q

Why have large-scale deforestation activities occurred?

A

● To provide land for cattle or rice fields
● To grow crops to produce biofuels

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14
Q

What is the greenhouse effect?

A

Greenhouse gases trap energy from the Sun as heat in the atmosphere, keeping the temperature on earth suitable for life.

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15
Q

What is causing global warming?

A

The increase in levels of greenhouse gases eg. carbon dioxide and methane, causing the temperature on earth to increase.

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16
Q

What are the harmful effects of deforestation?

A

● Destruction of many animals’ habitats
● Releases large amounts of
greenhouse gases

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17
Q

State the consequences of global warming.

A

● Rising sea levels
● Melting polar ice caps
● Changing weather patterns
● Migration of animals to find suitable habitats
● Tropical diseases becoming more common
● Extinction of species

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18
Q

Describe the steps taken to maintain biodiversity.

A

● Breeding programmes for endangered species.
● Protection and rebuilding habitats.
● Replanting field margins and hedgerows.
● Reduce deforestation.
● Reduce carbon dioxide emissions.
● Recycling rather than disposing in landfills.

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19
Q

What is the purpose of replanting hedgerows and field margins?

A

There is higher biodiversity in the margins than the fields that they surround.

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20
Q

What does a food chain show?

A

It describes the feeding relationships between organisms and the resultant stages of biomass transfer.

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21
Q

What are trophic levels?

A

The stages in a food chain

22
Q

How are trophic levels represented?

A

Trophic levels are represented by numbers, starting from 1. After 1, trophic levels are numbered according to far along the organism is in the food chain.

23
Q

What is trophic level 1?

A

Plants and algae which make their own food (through photosynthesis) - called producers.

24
Q

What is trophic level 2?

A

Herbivores which eat producers - called primary consumers.

25
Q

What is trophic level 3?

A

Carnivores that eat herbivores - called secondary consumers.

26
Q

What is trophic level 4?

A

Carnivores that eat other carnivores - called tertiary consumers.

27
Q

What is an apex predator?

A

A carnivore with no predators

28
Q

How do decomposers break down dead matter?

A

Decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules. Soluble small food molecules then diffuse into the
microorganisms.

29
Q

What is biomass?

A

The dry mass of all of the living organisms in an area.

30
Q

Why is dry mass used for biomass?

A

Because the wet mass varies as the volume of water in the organism varies.

31
Q

How do you calculate the efficiency of biomass transfer?

A

efficiency = (energy transferred / total energy available) × 100

32
Q

What percentage of the incident energy from light for photosynthesis do producers transfer?

A

1%

33
Q

What percentage of the biomass from one trophic level is transferred to the level above it in feeding?

A

≈ 10% (Approximately 10%)

34
Q

Why are biomass transfers not 100% efficient?

A

Energy is lost through:
- Egestion (removal of faeces)
- Excretion (removal of waste products e.g. urine containing urea and water)
- Respiration (loss of carbon dioxide and water) in which large amounts of glucose are used
- The production of inedible bones and shells

35
Q

How does the efficiency of biomass transfers affect the number of trophic levels in a biomass pyramid?

A

The less efficient the transfers, the fewer trophic levels and the fewer organisms in higher trophic levels.

36
Q

What is a biomass pyramid?

A

A pyramid that shows the total dry mass of organisms at each trophic level

Trophic level 1 is at the bottom of the pyramid

37
Q

What is a pyramid of numbers?

A

A pyramid of numbers shows the number of organisms at each trophic level

38
Q

Why are some pyramids of numbers not pyramid shaped?

A

Pyramids of numbers don’t take size and mass of organisms into account.

39
Q

Calculate the efficiency of this biomass transfer from the flowers to the caterpillar

-> (4000kJ lost) -> Flowers -> (are eaten by - 800kJ) -> caterpillar

A

efficiency = (energy transferred / total energy available) × 100

Total energy available = 800 kJ + 4000 kJ = 4800 kJ

Energy transferred = 800 kJ
800/4800 x 100 = 16.67%

40
Q

What is food security?

A

Having enough food to be able to feed a population.

41
Q

State the biological factors threatening food security.

A

● Rising birth rates
● Changing diets in developed countries → food is transported around the world
● New pests and pathogens
● Environmental changes affecting food production
● Increased cost of agriculture
● Armed conflicts

42
Q

How does intensive farming increase the production of animals?

A

● Feed animals high protein foods to increase growth.
● Reduce their energy loss to the environment:
○ Limiting movement
○ Regulating their surrounding temperature
● Feed animals antibiotics to prevent diseases.

43
Q

What are the advantages of intensive farming?

A

● Higher yield of food
● More efficient
● Allows easier quality control

44
Q

What are the disadvantages of intensive farming?

A

● May lead to antibiotic resistance.
● Cost is high.
● Ethical objections eg. limiting movement of animals may cause them harm.
● Biodiversity may be reduced.

45
Q

How can fish stocks be conserved?

A

● Control the size of gaps in fishing nets to prevent juvenile fish from being killed. before reaching reproductive maturity
● Introduce fishing quotas.

46
Q

What is a transgenic organism?

A

An organism that has been genetically modified to contain genetic material from another source.

47
Q

State an example of genetically modified foods.

A

Golden rice.

48
Q

How might crops be genetically modified?

A

● To improve nutritional value
● To be pest resistant
● To be pesticide resistant

49
Q

What are the advantages of golden rice?

A

It contains additional beta-carotene which can be converted to vitamin A in the body, supplementing people who do not obtain enough Vitamin A in their diet to prevent night blindness from forming.

50
Q

What is mycoprotein?

A

A protein-rich substance used to make meat substitute food for vegetarians and vegans.

51
Q

How is mycoprotein produced?

A

Fusarium, a fungus, is grown on glucose syrup, in aerobic conditions and the biomass is harvested and purified to get the mycoprotein.

Year 11 TRIPLE GCSE AQA Biology + Practicals (19 decks)

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