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Biology Paper 2 > B18 Biodiversity and ecosystems > Flashcards

B18 Biodiversity and ecosystems Flashcards

1
Q

What is an ecosystem?

A

The interaction of a community of living organisms with biotic and abiotic elements of their environment

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2
Q

What is an organism?

A

An individual animal or plant

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3
Q

What is a population?

A

The number of individuals of the same species living in a certain habitat

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4
Q

What is a community?

A

A group of interdependent living organisms in an ecosystem

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5
Q

What is a biotic factor and state some examples?

A

Living conditions e.g. the number of predators, availability of food, new pathogens etc

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6
Q

What is an abiotic factor and state some examples?

A

Non-living conditions e.g. soil pH, water levels, oxygen levels, temperature etc

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7
Q

What is a producer?

A

A photosynthetic organism that uses the sun’s energy to convert biomass into glucose by photosynthesis

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8
Q

What is a consumer?

A

An organism that eats other organisms

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9
Q

What is biodiversity?

A

The variety of all the different species of organisms on earth, or within an ecosystem

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10
Q

Explain why a high biodiversity ensures the stability of ecosystems

A
  • Each species may have a different function that contributes to the survival of other organisms in that ecosystem and themselves
  • Greater range and availability of food and prey to eat, species are not dependent on just one species for food
  • High biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment
  • Protects them from any changes in a given ecosystem
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11
Q

Explain why biodiversity plays a critical role in sustaining human populations

A
  • Humans depend on biodiversity for sustained food growth, for clean air and water and for medicine and shelter
  • Humans use the Earth’s resources, fossil fuels to generate electricity, for transport, and to make materials such as plastic, mineral from rocks and soil to grow food
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12
Q

Explain how the human population has affected our land

A
  • Vast areas of land are dug up for quarries to obtain rocks and metal ores
  • This reduces the land available for other organisms
  • Humans reduce the amount of land available for other animals by building, farming, quarrying and dumping waste
  • Toxic chemicals from industrial waste poison the soil
  • Landfill sites and sewage can pollute the soil
  • Deforestation leads to flooding
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13
Q

Explain how the human population has affected biodiversity

A
  • More and more land is used for building houses, shops, industrial sites and roads on
  • This destroys the habitats of other living organisms and reduces biodiversity
  • The waste produced by humans pollutes the environment and processing it takes up land, affecting biodiversity
  • Pollution reduces biodiversity
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14
Q

Explain how the human population has affected natural resources

A
  • The huge human population drains the resources of the Earth
  • People are readily using up finite reservers of metal ores and non-renewable energy resources such as crude oil and natural gas that cannot be replaced
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15
Q

Explain how the human population has affected our air

A
  • More and more air pollutants are released such as dust, which cause global dimming
  • Carbon dioxide and sulphur dioxide both cause acid rain
  • Smog causes respiratory problems
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16
Q

Explain how the human population has affected water

A

Eutrophication and bioaccumulation

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17
Q

What are the reasons for population explosion?

A
  • No natural predators
  • Better living conditions and education
  • Less infectious disease and better healthcare
  • Growing lots of food, the ability to farm intensively
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18
Q

What have been the effects of this rapidly rising population on the Earth’s resources?

A
  • Raw materials are rapidly being used up
  • Increasingly more waste is produced
  • Unless waste is properly handled more pollution will be caused
  • Habitats are being destroyed for building requirements of human population
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19
Q

Give two reasons why using herbicides can reduce biodiversity

A
  • Reduces plant life
20
Q

What are bioindicators?

A

An organism used as an indicator of the quality of an ecosystem, especially in terms of pollution

21
Q

State two substances that can pollute the air when they are released in the atmosphere

A
  • Carbon dioxide
  • Sulphur dioxide
22
Q

State two ways that water can become polluted

A
  • The runoff of chemicals from farmland (eutrophication)
23
Q

Name some greenhouse gases

A

Methane, water vapour and carbon dioxide

24
Q

Name an acidic gas that can lead to acid rain

A

Sulfur dioxide

25
Q

Name an effect of acid rain

A
  • Water pollution
  • Increases the acidity of water (lakes and ponds)
  • Corrodes limestone e.g. sculptures
  • Kills vegetation
26
Q

Name the cause of smog

A
  • Nitrogen oxides that react with sunlight
  • VOCs that are released from gasoline
27
Q

Why might it take a long time for bioaccumulation effects to be seen?

A

Not all animals are eaten

28
Q

What are the three main reasons for deforestation?

A
  • Provide land for cattle, for the beef market
  • To grow staple foods such as rice, or making cheap food int developed world such as palm oil
  • Grow crops that can be used to make biofuels based on ethanol
29
Q

What is deforestation?

A

The destruction of woodlands/forests by cutting down trees

30
Q

What issues arise from deforestation?

A
  • Less biodiversity
  • Increased carbon dioxide levels
  • Leaching and soil erosion
  • Disturbance of water cycle
  • Reduced photosynthesis due to loss of carbon sink
  • Micro-organisms feeding on decaying vegetation release carbon dioxide
31
Q

How does deforestation affect biodiversity?

A
  • Habitats like forests can contain a huge number of different species of plants and animals
  • When they are destroyed in deforestation, there is a danger of many species becoming extinct and biodiversity is reduced
32
Q

How does deforestation affect carbon dioxide levels?

A
  • Deforestation increases carbon dioxide levels in the atmosphere
  • Cutting down loads of trees means that the amount of carbon dioxide removed from the atmosphere during photosynthesis is reduced
  • Trees ‘lock up’ some of the carbon that they absorb during photosynthesis in their wood, which can remove it from the atmosphere for hundreds of years
  • Removing trees means that less is locked up
  • Carbon dioxide is released when trees are burnt to clear land
  • Microorganisms feeding on bits of dead wood and decaying vegetation releases carbon dioxide during respiration
33
Q

Suggest and explain two harmful effects on the environment caused by the destruction of large areas of trees

A
  • Increases carbon dioxide levels
  • Less carbon is absorbed by the trees and taken out of the atmosphere by photosynthesis
  • Carbon that is locked up inside these trees is released when the trees burn as carbon dioxide
  • Micro-organisms feeding on bits of dead wood also releases carbon dioxide during respiration
  • This increases carbon dioxide levels in the atmosphere and contributes to global warming
  • Reduces biodiversity as habitats are destroyed and can increase the chance of certain species becoming extinct
34
Q

What is food security?

A

Having enough available, affordable and nutritious food to feed a population

35
Q

Explain the factors affecting food security

A
  • The increasing birth rate has threatened food security in some countries
  • Changing diets in developed countries means scarce food resources are transported around the world
  • New pests and pathogens that affect farming
  • Environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
  • The cost of agricultural inputs
  • Conflicts that have arisen in some parts of the world which affect the availability of water or food.
36
Q

Explain how cost of agriculture affects food security

A
  • Scientists have produced crops genetically engineered to withstand droughts or floods, or increase yield
  • This has increased the cost of the seed
  • Fears that people that need these most are unable to afford them
  • sImilarly, irrigation systems, fertilisers, pesticides, all cost money, thus reducing food security for some
37
Q

Explain how conflicts affect food security

A
  • Conflict almost always leads to an increase in food insecurity
  • During war, there is an extended lean season: food shortages can turn into famine
  • Spring, violence prevents planting
  • Summer, no crops growing so stores are depleted
  • Fall, little to harvest and fighting closes markets
  • Winter, food runs out and no seeds are prepared
38
Q

Explain some solutions to food insecurity

A

Sustainable food production
- maintaining soil quality so plants grow well year after year
- more efficient ways to produce food
- allow continued production/harvesting e.g. taking care of fish stocks in our oceans so they do not run out

Alternative sources
- microbiology
- insects

39
Q

What is sustainability?

A

The avoidance of the depletion of natural resources to maintain an ecological balance

40
Q

Describe how the efficiency of food production can be improved

A
  • Limiting movement, so that they use less energy moving around
  • Controlling temperature, livestock are kept at their optimum temperature so that they use less energy regulating their body temperatures themselves
  • Prophylactic antibodies, prevent the risk of infection
  • Controlled lightning, used to make livestock sleep for longer (reduced movement)
  • Controlled feeding (high protein), modified food, use of growth hormones, to increase growth
41
Q

Why are certain fish stocks in the ocean decreasing?

A
  • Better technology of fishing vessels, they are bigger and are able to travel further
  • They also have more efficient ways of catching the fish
  • Overfishing
42
Q

What methods can be taken to make fishing more sustainable?

A
  • Imposing restrictions on fishing
  • Increased size of holes in the nets to only catch bigger fish
  • Smaller, younger fish are not caught
  • Restrictions on amount (quotas)
43
Q

Explain how fish farming is made more efficient

A
  • Fish are increasingly farmed to protect wild stocks, which have fallen sharply due to overfishing
  • They are kept in cages, fed a high protein
  • They grow quickly but there are obvious ethical concerns
44
Q

What is mycoprotein?

A

Produced from the Fusarium fungus, which grows and reproduces rapidly using cheap sugar syrup in fermenters

45
Q

What are disadvantages of intensive farming methods?

A
  • Some people believe them to be unethical
  • Diseases spread more rapidly
  • Antibiotics can build up in the food chain, over use of antibiotics
  • Increased use of fossil fuels for heating
46
Q

Suggest two reasons why it is more efficient to rear cows indoors than to rear cows outdoors

A
  • Warmer indoors so less energy wasted in keeping warm
  • Less movement indoors so less energy wasted
47
Q

Explain how the intensive farming of pigs increases the efficiency of food production

A
  • The pigs are kept inside or in a temperature controlled environment
  • They are also kept enclosed or in a restricted environment
  • So less energy is lost in controlling body temperature
  • Less energy used for movement
  • So more energy is available for growth
  • Less energy is transferred to the surroundings

Biology Paper 2 (10 decks)

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