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A Level Biology OCR A > 11 - Biodiversity > Flashcards

11 - Biodiversity Flashcards

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1
Q

What is species richness?

A

The number of different species living in an ecosystem

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2
Q

What is species evenness?

A

A comparison of the numbers of individuals of each species living in a community

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3
Q

What is a community?

A

All the populations of living organisms in a particular habitat

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4
Q

What is a keystone species?

A

One which has a large effect on its environment compared to its abundance

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5
Q

What would happen if a keystone species were removed from a habitat?

A

The habitat would be very different, and biodiversity reduced

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6
Q

What are 3 reasons for maintaining biodiversity?

A
  1. Ecological- protecting keystone species and maintaining genetic resource 2. Economic- e.g. reducing soil depletion from monoculture will increase further yields 3. Aesthetic- protecting landscapes for the benefit of human enjoyment
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7
Q

What are the two components of species biodiversity?

A

Species evenness and species richness

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8
Q

What is the general rule linking habitat biodiversity and species biodiversity?

A

Generally, as habitat biodiversity increases, so does species biodiversity

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9
Q

What is habitat biodiversity?

A

The number of different habitats found within an area

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10
Q

What is genetic biodiversity?

A

The variety of genes which make up a species

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11
Q

What are some advantages of greater genetic biodiversity?

A

Allows for better adaptation to a changing environment and is more likely to result in individuals who are resistant to disease

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12
Q

What is sampling?

A

Taking measurements of a limited number of individual organisms in a given area

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13
Q

What is the abundance of an organism?

A

The number of individuals of a species present in an area

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14
Q

What are the two forms of sampling?

A

Random and non-random

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15
Q

How would you decide which organisms to study in a random sample?

A

By using a random number generator or computer tables

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16
Q

What are the 3 main techniques used in non-random sampling?

A
  1. Opportunistic 2. Stratified 3. Systematic
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17
Q

What is opportunistic sampling and what is its major limitation?

A

Simply selecting whichever organisms are available; limited as it may not provide a representative sample

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18
Q

What is stratified sampling?

A

Dividing a population into a number of sub-groups based on a certain characteristic, then taking a random sample from each strata representative to its size

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19
Q

How are systematic samples often carried out?

A

Using a belt or line transect

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20
Q

What is the difference between belt and line transects?

A

Line transect involves sampling all organisms found on a line, whereas belt transect samples all organisms found in the area between two parallel lines, making it more accurate

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21
Q

What are two factors which affect the reliability of a sample?

A

Chance and sampling bias

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22
Q

How can the effects of sampling bias be reduced?

A

By using random sampling

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23
Q

What is sampling bias?

A

Where the selection process of a sample is biased, whether accidentally or deliberately

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24
Q

How can the effects of chance on sampling reliability be reduced?

A

By using a larger sample size

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25
Q

How does chance affect the reliability of a sample?

A

The organisms selected may, by chance, not be representative of the whole population

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26
Q

Why would you normally use more than one sampling technique at each sample point?

A

So that a range of data could be collected

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27
Q

What are 5 techniques used to sample animals?

A
  1. Pooter 2. Tree beating 3. Sweep nets 4. Pitfall traps 5. Kick sampling
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28
Q

What is a pooter and how is it used?

A

Used to catch small insects, a pooter is used by sucking on a mouthpiece connected to an inlet tube, which draws the insects into a holding chamber; a filter before the mouthpiece stops the insects going into the sampler’s mouth

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29
Q

What is tree beating?

A

Where a white sheet is stretched under a tree or bush, and the plant is the shaken/beaten, causing invertebrates within it to fall onto the sheet

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30
Q

What are sweep nets?

A

Large nets used to catch insects in long grass

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31
Q

What are pitfall traps?

A

A hole used to catch small, crawling invertebrates, which must be deep enough that they can’t get out, have a cover to stop the hole filling with rainwater, and be left overnight to ensure that nocturnal species are also sampled

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32
Q

What is kick sampling?

A

Used to study river-dwelling organisms- the river bank and bed are kicked for a period of time, and a net is held downstream for a set period of time to catch any dislodged organisms

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33
Q

What are quadrats used to sample?

A

Plants and slow-moving animals such as barnacles and mussels

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34
Q

What are the two types of quadrat?

A

Point quadrat and frame quadrat

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35
Q

What is a point quadrat?

A

A frame with a horizontal bar; at set intervals along the bar, a pin is pushed through, and any organisms touching the pin are sampled

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36
Q

What is a frame quadrat?

A

A square frame divided into a grid with equal-sized sections, with the type and number of each species in each section recorded

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37
Q

What are 6 things which we would tend to measure and their units?

A
  1. O₂ content (mg/dm³) 2. Temperature (°C or K) 3. Wind speed (m/s) 4. Light intensity (Lx) 5. Relative humidity (mg/dm³) 6. pH (standard pH scale)
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38
Q

How is wind speed measured?

A

Using an anemometer

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39
Q

How are oxygen content, temperature, pH, relative humidity and light intensity measured?

A

Using an ‘x’ probe (with x being the thing measured)

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40
Q

What are the 3 main ways you can use a frame quadrat to sample plants?

A
  1. Density (i.e. number) 2. Frequency (i.e. how many squares the organisms are present in 3. Percentage cover, useful when a particular species is abundant or difficult to count
41
Q

What are abiotic factors?

A

The non-living conditions within a habitat, which have a direct effect on the organisms living there

42
Q

What are some advantages of abiotic factors being able to be measured using sensors?

A
  1. Rapid changes can be detected 2. Human error in taking reading reduced 3. High degree of precision can be achieved 4. Data can be stored or tracked on a computer
43
Q

What is a common technique used to measure animal population size?

A

Capture-mark-release-recapture

44
Q

What assumptions do you need to make when using capture-mark-release-recapture?

A

No death, no immigration or emigration, identical sampling methods used, marking has not affected survival rate of animal

45
Q

How would you estimate population size using capture-mark-release-recapture?

A

(1st sample size multiplied by 2nd sample size) divided by number of marked animals in 2nd sample

46
Q

What is the simplest way to measure an area’s biodiversity?

A

Measuring species richness

47
Q

What is a better way to measure biodiversity than just using species richness and why?

A

Simpson’s index of biodiversity, as it takes into account both species richness and species evenness

48
Q

What would you have to do before using Simpson’s Index of Biodiversity?

A

Estimate population size

49
Q

What does a value closer to one on Simpson’s Index of Biodiversity show us?

A

Higher biodiversity

50
Q

Why is it important to conserve some areas with low biodiversity, as well as those with high biodiversity?

A

As the habitats with low biodiversity may have extreme conditions, and so may have rare species which are specialised to those conditions, and would be less able or unable to survive elsewhere

51
Q

What are some features of a habitat with high biodiversity?

A

Large number of successful species, complex food webs, environmental changes often have a small effect on ecosystem as a whole, relatively benign environment, many species in habitat, often with few specific adaptations to environment

52
Q

What are some factors which would cause genetic biodiversity to increase?

A

Mutations in gene pool creating new alleles, or interbreeding between different populations

53
Q

What is gene flow?

A

When an individual migrates from one population and breeds with a member of another population, transferring alleles between the two populations

54
Q

What are some factors which could lead to genetic biodiversity decreasing?

A

Rare breeds, captive breeding programs, selective breeding, artificial cloning, natural selection, genetic bottlenecks, the Founder Effect, genetic drift

55
Q

What is a genetic bottleneck?

A

Where only few individuals within a population survive an event or change, thus reducing the size of the gene pool

56
Q

What is the Founder Effect?

A

Where a small number of individuals create a colony geographically isolated from the original population, with a small gene pool for the new colony

57
Q

What is Genetic Drift?

A

Changes in the frequency of occurrence of alleles over time, which tend to be more pronounced in populations with low genetic biodiversity

58
Q

What is a method used to quantify genetic biodiversity?

A

Measuring the proportion of polymorphic gene loci using number of polymorphic gene loci divided by total number of gene loci

59
Q

What are the 4 main ways in which humans negatively affect biodiversity?

A
  1. Agriculture 2. Climate change 3. Pollution 4. Deforestation
60
Q

How does deforestation negatively affect biodiversity?

A
  1. Directly reduces number of trees present 2. Destroys habitats for animals 3. Reduces species evenness if a specific type of tree is felled for commercial reasons 4. Forces migration of animals
61
Q

Why does replanting forests not necessarily increase biodiversity to its previous level?

A

Generally, only a few, commercially viable species of trees are planted

62
Q

What is monoculture and how does it affect biodiversity?

A

Where farmers only grow one type of crop on large areas of land- obviously reduces plant biodiversity, as well as negatively affecting animal biodiversity as only a few species can be supported by one species of plant in most cases

63
Q

What are some methods used in agriculture which can negatively affect biodiversity?

A

Monoculture, use of herbicides and pesticides (which reduce biodiversity by killing all the ‘pest’ and weed species), deforestation, removal of hedgerows

64
Q

What will happen in terms of biodiversity if climate change occurs slowly?

A

Species may have time to adapt or move to new areas, which may lead to the loss of native species, but also the migration of new species to the area, so biodiversity may not necessarily be lost

65
Q

What are some ways in which climate change could negatively affect biodiversity?

A

Melting of polar ice caps leads to extinction of organisms in these areas, rising sea levels could flood low-lying habitats, insect life cycles and populations would change (important as they are often keystone species), high temperatures and low rainfall could cause extinction of some plant species and increased domination of xerophytes, which would also affect populations of animals which feed on them

66
Q

What is an environmental effect of continuous monoculture?

A

Soil depletion, which makes the ecosystem more fragile

67
Q

Can humans have a positive effect in terms of increasing biodiversity?

A

Yes- in the UK, as well as many other countries, the natural habitat is created by human intervention and management of the land

68
Q

What are the two broad categories of conservation?

A
  1. In situ (within the natural habitat) 2. Ex situ (out of the natural habitat)
69
Q

What are the 4 categories of organisms which are threatened by extinction?

A
  1. Extinct- no organisms of the species exist anywhere in the world 2. Extinct in the wild- organisms of the species exist only in captivity 3. Endangered- a species that is in danger of extinction 4. Vulnerable- a species that is considered likely to become endangered in the near future
70
Q

What is sustainable development?

A

Economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs

71
Q

Is ex situ or in situ conservation cheaper?

A

In situ

72
Q

What does in situ conservation maintain which ex situ conservation may not?

A

The genetic diversity of the species, evolutionary adaptations to changing environmental conditions, interdependent relationships within a habitat

73
Q

What are examples of areas designated for the in situ conservation of wildlife?

A

Nature reserves and marine conservation zones

74
Q

What are some examples of active management techniques used in in situ wildlife reserves?

A

Controlled grazing, restricting human access, controlling poaching, feeding animals, reintroduction of species, culling or removal of invasive species, halting succession

75
Q

Why is tourism allowed in wildlife reserves?

A

To boost finances, and because it is heavily controlled

76
Q

What is succession?

A

The natural process in which early colonising species are replaced over time until a stable mature population is reached

77
Q

Why are large areas needed for marine reserves?

A

The target species often move large distances, or breed in geographically different areas

78
Q

When is ex situ conservation usually used?

A

In conjunction with in situ conservation

79
Q

What are 3 examples of ex situ conservation methods?

A
  1. Seed banks 2. Botanic gardens 3. Captive breeding programs
80
Q

How are species managed in botanic gardens?

A

They are actively managed to give them the resources to grow

81
Q

What is a seed bank an example of?

A

A gene bank (a store of genetic material)

82
Q

How are seeds stored in seed banks and why is it done this way?

A

They are dried and cooled to temperatures of -20°C, which maintains their viability by slowing down the rate at which they lose the ability to germinate

83
Q

Why don’t seed banks work for all plants?

A

Some seeds die when dried and frozen, including the seeds of many plants from tropical rainforests

84
Q

What do captive breeding programs do?

A

Produce offspring of a species in a human-controlled environment

85
Q

Who are captive breeding programs often run by?

A

Zoos and aqauriums

86
Q

What do scientists working on captive breeding programs aim to do?

A

Aim to create a stable, healthy population of a species, then gradually reintroduce the species back into its natural habitat

87
Q

What do captive breeding programs provide the animals with?

A

Shelter, plenty of nutritious food, absence of predators, veterinary treatment, semen or mates from other breeding programs or zoos

88
Q

What is a problem with captive breeding programs and how is this somewhat overcome?

A

Maintaining genetic diversity, as problems related to inbreeding can occur due to the small population. To overcome this an international genealogical catalogue is maintained, and breeding is arranged to maximise genetic diversity

89
Q

What are some reasons that animals born through captive breeding programs may be unsuitable for return to the wild?

A
  1. Lack of resistance to diseases 2. Lack of learned behaviour 3. Their genetic makeup becoming so different to that of the wild population that the two cannot interbreed 4. Lack of suitable wild habitat
90
Q

What are three agreements to do with conservation?

A
  1. Rio Convention 2. CITES 3. Countryside Stewardship Scheme
91
Q

Give a brief summary of CITES.

A

A treaty first introduced in 1975 which regulates the international trade of animals, plants and animal and plant products. Over 35,000 species are today protected by this convention

92
Q

What 3 conventions form the 1992 Rio Convention?

A
  1. Convention on Biological Diversity, which requires countries to create a national framework on sustainable development 2. UN Convention on Climate Change 3. UN Convention on Desertification
93
Q

How many countries were at the Rio Convention?

A

172

94
Q

What organisation oversaw the Rio Convention?

A

The UN

95
Q

Give a brief summary of the Countryside Stewardship Scheme.

A

A series of government grants to farmers and land managers to incentivise enhancing and conserving the natural landscape. Ran from 1991-2014, when it was replaced by the similar Environmental Stewardship Scheme

96
Q

What was the general aim of the Countryside Stewardship Scheme?

A

To make conservation a part of normal farming and land management practice

97
Q

What were four specific aims of the Countryside Stewardship Scheme?

A
  1. Improve opportunities for countryside enjoyment 2. Improving, extending and creating wildlife habitats 3. Sustaining the beauty and diversity of the landscape 4. Restoring neglected land and conserving archaeological and historic features
98
Q

What is conservation?

A

The name given to preservation and careful management of the environment and of natural resources

A Level Biology OCR A (23 decks)

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