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OCR Biology AS Level > 4.2 - Biodiversity > Flashcards

4.2 - Biodiversity Flashcards

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1
Q

Define biodiversity.

A

The measure of variation in the living world

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2
Q

What are the 2 types of variation?

A
  1. Continuous (e.g. Shoe size)

2. Discontinuous (eye colour)

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3
Q

How do scientists use sampling to measure biodiversity?

A

They focus on one specific section of an area and then extrapolate the data collected for the rest of the area.

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4
Q

Why does taking one sample of an area provide unreliable information for the whole area?

A

You’re not genuinely considering the other sections of the area.

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5
Q

What are the 4 main approaches that scientists use to choose which parts of the area are studied?

A
  1. RANDOM
  2. OPPORTUNISTIC
  3. STRATIFIED
  4. SYSTEMATIC
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6
Q

What is RANDOM sampling?

A

Sample sites are chosen in random.

The area may be divided into a grid and a computer can randomly generate coordinates.

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7
Q

Give 1 advantage and 1 disadvantage of random sampling.

A

Advantage: It’s unbiased
Disadvantage: It may not cover the area evenly

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8
Q

What is OPPORTUNISTIC sampling?

A

When you’re starting to already collect data in an area, but then you go and choose sections of the area that may interest you

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9
Q

Give 1 advantage and 1 disadvantage of opportunistic sampling.

A

Advantage: Easier, quicker, more data to be offered
Disadvantage: Highly biased data

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10
Q

What is STRATIFIED sampling?

A

When you divide the habitat into areas which seem different and then you sample each area separately.

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11
Q

Give 1 advantage and 1 disadvantage of stratified sampling.

A

Advantage: Even coverage of species
Disadvantage: Over-representation of larger areas

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12
Q

What is SYSTEMATIC sampling?

A

When you take samples at fixed intervals

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13
Q

Give 1 advantage and 1 disadvantage of systematic sampling.

A

Advantage: Good if you want to see a gradient

Disadvantage: Easy to miss species because you’re only sampling a tiny area and can lead to underestimates of biodiversity.

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14
Q

What 4 things must you do/have before sampling plants?

A
  1. Wear appropriate clothing
  2. Apparatus
  3. Clipboard, pen, paper
  4. Keys to identify plants (guides that have pictures)
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15
Q

What are the 4 methods of sampling plants?

A
  1. QUADRAT
  2. POINT FRAME
  3. LINE TRANSECT
  4. BELT TRANSECT
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16
Q

How is a quadrat used?

A

Placed by random coordinates generated by a computer. You can estimate the percentage cover of species by counting how many squares they cover.

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17
Q

How is a line transect used?

A

A tape measure is laid down and the number of species touching the line are counted.

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18
Q

How is a belt transect used?

A

A tape measure is laid down and quadrats are placed along the line at fixed intervals (example of systematic sampling)

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19
Q

What are the 2 types of belt transects?

A
  1. DISCONTINUOUS/INTERRUPTED: Fixed intervals of quadrats

2. CONTINUOUS: Creating a whole pattern of quadrats side-by-side

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20
Q

What are 2 issues with sampling animals?

A
  1. Animals move a lot, they may be scared

2. They may be too small to see

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21
Q

How do scientists obtain DNA to sample animals?

A

They obtain DNA from the droppings/burrows. They’re taken to the lab to be studied.

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22
Q

What are 6 ways to catch animals?

A
  1. SWEEP NET
  2. POOTER
  3. PITFALL TRAP
  4. TULLGREN FUNNEL
  5. LIGHT TRAP
  6. LONGWORTH TRAP
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23
Q

How does a POOTER work?

A

There are 2 straws, 1 in the ground and 1 in your mouth. You suck air from the straw so that the insect is sucked in the jar.

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24
Q

How does a pitfall trap work?

A

You dig a hole and put a container within it and fill it with water.

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25
Q

How does a Tullgren funnel work?

A

You put leaf litter in a funnel.
A light shines onto the leaves which dries them up.
This drives the animals who like to live in moisture down through the funnel and into a collecting jar.

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26
Q

How does a light trap work?

A

By leaving UV light at night with a jar underneath the light containing alcohol

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27
Q

How does a Longworth trap work?

A
  • a small metal box with food in it and a one-way door
  • doesn’t harm the animals and is effective
  • you use the mark-and-recapture technique
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28
Q

Describe the Mark-and-Recapture technique in Longworth traps.

A
  1. The number of animals captured in the first round are marked as C1
  2. You then release them and recapture them in the 2nd round. The number captured is C2.
  3. The number of animals that were marked in the 2nd round is C3.
  4. Use the formula ‘Total Population’ = C1 x C2 / C3
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29
Q

What is species evenness?

A

A measure of how evenly represented the species are

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30
Q

What is species richness?

A

A measure of how many different species are present

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31
Q

How do you calculate the frequency of an organism in an area?

A

Count the organisms and then divide by the area surveyed

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32
Q

What does Simpson’s Index take into account?

A

Species richness and evenness

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33
Q

The formula for Simpson’s Index is D=1-[Σ〖(n/N)〗^2] .

What is represented by each variable?

A
  • D: Simpson’s Index
  • n: number of individuals of particular species or % cover for plants
  • N: total number of individuals of all species or % cover for all plants
34
Q

What is a loci (plural: locus)?

A

A position on a chromosome

35
Q

What is an allele?

A

A genetic variant

36
Q

What does Genetic Diversity check for?

A

How many genes have more than 1 allele

37
Q

What is the formula for Genetic Diversity?

A

Genetic diversity (%) = (loci with more than 1 allele / total loci) x 100

38
Q

Define ‘interdependence of organisms’.

A

The idea of how certain species depends on one another

39
Q

What is the Keystone species?

A

The disproportionate effect on the environment relative to their abundance.

40
Q

If the grass is eaten by a deer which is eaten by a cougar, what would happen to the deers if cougars became extinct?

A

At first, the deer population will dramatically increase because there’s more grass to eat.
But then the grass population will decrease because it’s excessively eaten so the deer will soon become extinct.

41
Q

What is an example of a Keystone species (other than the cougar example)?

A

Beavers build a dam that has a huge effect on the habitat.

The dam creates still water in which many other species can live.

42
Q

State 3 main reasons of maintaining biodiversity.

A
  1. GENETIC RESOURCES
  2. ECONOMIC REASONS
  3. AESTHETIC REASONS
43
Q

In terms of genetic resources, why is it important to maintain biodiversity?

A

There are many species that we don’t know of yet that can be of great genetic use.
If we lose these species, we can potentially lose solutions to climate change and medicines/vaccines.

44
Q

In terms of economic reasons, why is it important to maintain biodiversity?

A

Many organisms purify water, form and fertilise soils, help to pollinate crops, etc.
The organisms themselves are also used for food/fuel/timber.
These factors impact food production.

45
Q

How does soil depletion arise (3)?

A
  1. In agriculture, crops are grown in a MONOCULTURE fashion (lots of the same strain of species)
  2. These species will start to drain the soil of the same minerals
  3. This will lead to erosion which can lead to dust storms and may enable flooding.
46
Q

What are 3 factors affecting biodiversity?

A
  1. HUMAN POPULATION GROWTH
  2. AGRICULTURE
  3. CLIMATE CHANGE
47
Q

How does the human population growth affect biodiversity?

A

We destroy habitats, pollute them, alter ecosystems to get food, deplete resources, etc.

48
Q

How do monoculture crops affect biodiversity?

A

Reduces biodiversity because you are getting rid of all the variation that was there in the crop before by simply breeding one strain.
You’re also reducing it further because usually the area is deforested for monoculture crops to grow.

49
Q

How does selective breeding affect biodiversity?

A

Selective breeding is generally focused towards human goals. This completely overlooks the variation within plants,

(e.g. we can selectively breed for insect resistance but in doing so will lose the great use of plants)

50
Q

How does climate change affect biodiversity?

A

As the climate starts to change rapidly, the less biodiverse ecosystems become less able to adapt to these changes so extinction can arise.

51
Q

What is conservation in situ?

A

Conserving species within their natural habitat.

52
Q

What is the goal of conservation in situ?

A

To minimise human impact on the natural environment and to protect it

53
Q

What are 2 ways of achieving conservation in situ?

A
  1. LEGISLATION

2. WILDLIFE RESERVES

54
Q

What is legislation (in the context of conservation in situ)?

A

Making certain activities illegal.

e.g. hunting, logging, clearing land, etc.

55
Q

Give 2 disadvantages of legislation.

A
  1. Specific to countries so it can be difficult to persuade some countries that the legislation’s necessary
  2. Difficult to enforce
56
Q

What are wildlife reserves?

A

Designated areas established for conservation of habitats and species.

57
Q

What are 3 factors to choosing a reserve?

A

Use the acronym ‘CAR’:
Comprehensive uses: how many species are there? What are the environmental conditions like?

Adequacy: Is the area large enough to provide survival for both the short and long term?

Representativeness: Is there a full range of diversity within the species and conditions?

58
Q

What do you need to consider when establishing a wildlife reserve?

A

The local people/traditions. They may not agree of what has been taken into account which can lead to conflicts.

59
Q

Give 5 examples of wildlife reserves.

A
  1. National parks in the UK
  2. National Nature Reserves
  3. Sites of Special Scientific Interests
  4. Local Nature Reserves
  5. Marine conservation zones
60
Q

Give 5 advantages of conservation in situ.

A
  1. Conserved in their natural habitat
  2. Permanent protection of biodiversity, natural and cultural heritage, ecosystems, etc.
  3. Allows for management of areas
  4. Ecologically sustainable uses of land
  5. Facilitates scientific research
61
Q

Give 4 disadvantages of conservation ex situ.

A
  1. Endangered habitats may already be fragmented - difficult to find an area.
  2. Population may have already lost much of its genetic diversity
  3. Conditions which caused damage/extinction may still be present.
  4. “Honeypot” for poachers and tourists.
62
Q

What is conservation ex situ?

A

Conservation through activities which take place outside a species’ normal habitat.

63
Q

What are 3 methods of conservation ex situ?

A
  1. ZOOS
  2. BOTANIC GARDENS
  3. SEED BANKS
64
Q

How can you restore the population in a zoo? Give 4 ways.

A
  1. Freezing sperm, eggs and embryos
  2. Artificial insemination
  3. In vitro fertilisation
  4. Embryo transfer
65
Q

Give 7 advantages of zoos.

A
  1. Protected from predation and poaching
  2. Easy to monitor/measure
  3. Populations can be divided
  4. Selective breeding
  5. Repopulation
  6. Can be used to raise funds
  7. Educational
66
Q

Give 6 disadvantages of zoos.

A
  1. Exposure to diseases
  2. Animals out of their natural habitat - abnormal behaviour
  3. Limited genetic diversity
  4. Reproduction can be difficult
  5. Reintroduction to a new environment
  6. Expensive to maintain
67
Q

What are botanic gardens?

A

Sites were seeds are stored and are germinated under controlled conditions.

68
Q

Give 5 advantages of botanic gardens.

A
  1. The dormant stage (seed) is much easier to conserve than sperm
  2. Collection of the seeds is relatively simple and there’s minimal disturbance
  3. Easier to breed because most of them asexually breed
  4. Also possible to reproduce plants using tissue culture - far quicker method (clones)
  5. Replanting is relatively easy
69
Q

Give 6 disadvantages of botanic gardens.

A
  1. Funding is difficult to find because not many people are interested in sponsoring plants unlike animals
  2. You’re still disturbing the plants even though it’s not much
  3. The genetic diversity within the botanic gardens might not be representative
  4. Replanting seeds in a different area can be difficult because the seeds might have a mutation that’s not allowing them to flourish in new areas
  5. Seeds, if kept in the wrong way, may not be viable
  6. Asexual breeding/tissue culture decrease genetic diversity (because they’re clones)
70
Q

What are seed banks?

A

Sites like botanic gardens but focus on the seed aspect only

71
Q

What is an example of a seed bank?

A

Kew Millenium Seed Bank

72
Q

How are seeds conserved in seed banks?

A

Dry/freezing conditions - for every 1% decrease in moisture, the lifespan of a seed doubles

73
Q

What are 3 examples of International Cooperation organisations?

A
  1. CITES (Convention on International Trade in Endangered Species (of wild flora and fauna)
  2. Rio Convention on Biological Diveristy
  3. Countryside Stewardship Scheme (local)
74
Q

Give 5 aims of CITES.

A
  1. Regulate and monitor international trades in selected species
  2. Ensures that the trade does not endanger survival of populations in the wild
  3. Prohibits the trade in wild plants for commercial purposes
  4. Allows the trade of artificially propagated plants subject to permit
  5. Slightly less endangered wild species may be traded subject to permit
75
Q

What is 1 disadvantage of CITES?

A

Difficult to enforce - smuggling (more endangered species means more money)

76
Q

Give 5 aims of the Rio Convention of Biological Diversity.

A
  1. Conservation of biodiversity
  2. Sustainable use of its components (of the ecosystem)
  3. Appropriate shared access to genetic resources
  4. Appropriate sharing and transfer of scientific knowledge and technologies
  5. Fair and equitable sharing of the benefits arising out of the use of genetic resources
77
Q

Give 1 GENERAL advantage of the Rio Convention of Biological Diversity.

A

Encourages cooperation between states

78
Q

Give 1 advantage SPECIFIC TO ZOOS of the Rio Convention of Biological Diversity.

A

A lot of time/effort/distress to the animals can be reduced by importing genetic material from other countries

79
Q

Give 1 advantage SPECIFIC TO BOTANIC GARDENS of the Rio Convention of Biological Diversity.

A

Plant-breeding programmes can be enhanced by sharing genetic material.

80
Q

Give 1 advantage SPECIFIC TO SEED BANKS of the Rio Convention of Biological Diversity.

A

Benefit from having more seeds from different countries - those seeds can be duplicated and split across many seed banks to reduce the chance of extinction.

81
Q

What are the 3 aims of the Countryside Stewardship Scheme.

A
  1. Improves natural beauty and diversity of the countryside
  2. Enhances, restores and recreates targeted landscapes
  3. Improve opportunities for public access

OCR Biology AS Level (13 decks)

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