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A-Level OCR Biology > Chapter 11 - Biodiversity > Flashcards

Chapter 11 - Biodiversity Flashcards

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1
Q

What are the 3 types of biodiversity?

A
  • Habitat biodiversity
  • Species biodiversity
  • Genetic biodiversity
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2
Q

What is habitat biodiversity?

A

The number of different habitats found within a particular area

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3
Q

What are the two types of species biodiversity?

A

Species richness

Species evenness

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4
Q

What is species richness?

A

The number of different species living in a particular area

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5
Q

What is species evenness?

A

A comparison of the numbers of individuals of a species living in a particular area

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6
Q

What is genetic biodiversity?

A

The variety of genes that make up a species

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7
Q

What is the advantage of a greater genetic biodiversity?

A

More likely to have better adaptions for new/different selection pressures (e.g. the introduction of a new disease, species with higher genetic biodiversity are more likely to be resistant)

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8
Q

What is sampling?

A

Taking measurements of a limited number of individuals present in a particular order

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9
Q

What is random sampling?

A

Selecting individuals by complete chance, in which each individual in the population has an equal likelihood of selection

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10
Q

What are the 3 types of non-random sampling?

A

Opportunistic
Stratified
Systematic

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11
Q

What is opportunistic sampling?

A

When you select organisms that are conveniently available

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12
Q

What is stratified sampling?

A

When a population is divided into different sub-groups (strata), and then a random sample is taken from these strata

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13
Q

What is systematic sampling?

A

When samples are taken at specified and periodic points in a specific area

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14
Q

Example of systematic sampling

A

Taking samples of rock along a beach, every metre along a transect

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15
Q

What 2 factors that decrease reliability of results?

A
  • Sampling bias

- Chance (outliers)

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16
Q

What is a pooter used for?

A

Catching small insects

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17
Q

What is a sweep net used for?

A

Catching insects in areas of long grass

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18
Q

What is a pitfall trap used for?

A

Catching small, crawling invertebrates (e.g. beetles, spiders and slugs)

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19
Q

What is tree beating used for?

A

Catching invertebrates in a tree

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20
Q

What is kick sampling used for?

A

Catching organisms living in a river

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21
Q

What are plants usually sampled using?

A

A quadrat

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22
Q

What are the two types of quadrat?

A

Point quadrat

Frame quadrat

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23
Q

What is a point quadrat?

A

A frame containing a horizontal bar, in which at set intervals along the bar, a pin can be pushed through to reach the ground. Each species of plant the pin touches is recorded

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24
Q

What is a frame quadrat?

A

A square frame divided into a grid of equal sections

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25
Q

What are the 3 things you measure using a quadrat?

A

Density
Percentage cover
Frequency

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26
Q

How do you measure density using a quadrat?

A

Count the number of a given plant/s in a 1x1; this will then give you density per square metre

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27
Q

How do you measure frequency using a quadrat?

A

Count the number of squares in which a given species is present. For example if a plant was present in 65 of 100 squares, it would give the plant a percentage of occurrence of 65%

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28
Q

How do you measure percentage cover using a quadrat?

A

Estimate (by eye) the percentage within a quadrat a given species covers

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29
Q

What is the main technique to determine population size over a large area?

A

Capture-mark-release-recapture

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30
Q

What are abiotic factors?

A

Non-living conditions in a habitat (e.g. temperature)

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31
Q

What do you use to measure wind speed?

A

Anemometer

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32
Q

What do you use to measure light intensity?

A

Light meter

33
Q

What do you use to measure humidity?

A

Humidity sensor

34
Q

What do you use to measure pH?

A

pH probe

35
Q

What do you use to measure temperature?

A

Temperature probe

36
Q

What do you use to measure oxygen content in water?

A

Dissolved oxygen probe

37
Q

What is a calculation to measure biodiversity?

A

Simpson’s Index of Diversity

38
Q

What 2 things do you need to calculate Simpson’s Index of Biodiversity?

A

The total number of organisms of all species

The total number of organisms of a particular species (for each species)

39
Q

Why is Simpson’s Index a good way of measuring biodiversity?

A

It takes both species evenness and richness into account

40
Q

What factors increase genetic biodiversity?

A
  • Genetic mutations

- Gene flow

41
Q

What is gene flow?

A

When an individual from one population breeds with an individual from a different population, so alleles/DNA are transferred between the two populations

42
Q

What is selective breeding?

A

Where only a few individuals within a population are selected to be bred due to their advantageous characteristics- this decreases genetic biodiversity

43
Q

What are captive breeding programs?

A

Where only a small number of captive individuals are available for breeding- this means there is a small gene pool so low genetic biodiversity

44
Q

How does natural selection affect genetic biodiversity?

A

During natural selection, alleles for less advantageous characteristics will be eventually lost from a population- this therefore leads to a reduction in genetic biodiversity

45
Q

What is genetic drift and give an example of it?

A

When the frequency of alleles changes as a result of a random occurrence.
For example, a meteor could hit a random area of a population and reduce the frequency of certain alleles from the population of a species in a unequal way

46
Q

What is polymorphism/polymorphic genes?

A

Genes with more than one possible allele

47
Q

How do you calculate the proportion of genes that are polymorphic?

A

Proportion of polymorphic gene species = number of polymorphic gene species/total number of species

48
Q

How does deforestation affect biodiversity?

A
  • Felling specific types of trees but leaving others reduces the biodiversity of trees in that area
  • Destroys the habitat of many species, causing many to reduce in number, and also forcing many to other areas. These both have a knock-on effect on the balance of the food web, which will result in a decrease in biodiversity
49
Q

What are the 3 main human causes of reduced biodiversity?

A
  • Deforestation
  • Climate change
  • Agriculture
50
Q

3 ways in which agriculture affects biodiversity

A
  • Deforestation
  • Monoculture
  • Pesticides + herbicides
51
Q

What is monoculture and how does it affect biodiversity?

A

Where a large area of land is used for the growth of a single crop- this therefore reduces the biodiversity of that area

52
Q

How do pesticides and herbicides affect biodiversity?

A

They kill pests/weeds that would otherwise be growing in that area, reducing biodiversity

53
Q

3 ways in which climate change affects biodiversity

A
  • Ice caps melting = loss of polar habitats
  • Sea levels rising = flooding = loss of habitat
  • Higher temperatures = harder to survive for certain organisms
54
Q

What are the 3 broad categories of the importance of maintaining biodiversity?

A
  • Aesthetic
  • Economic
  • Ecological
55
Q

Aesthetic reasons for maintaining biodiversity:

A
  • Presence of plants and animals enriches our lives, such as through reducing stress
  • Natural world is often inspiration for people such as artists and writers, which in turn provide pleasure for us
56
Q

Economic reasons for maintaining biodiversity:

A
  • Maintain soil fertility = countries are able to continue to cultivate their own crops
  • Non-sustainable harvesting = eventual loss of that resource = collapse of the industry
  • Lack of (genetic) biodiversity = easier to get wiped out by certain selection pressures = widespread famine (e.g. Irish potato famine, which resulted in 1 million deaths)
  • Biodiverse areas attract tourism
57
Q

Ecological reasons for maintaining biodiversity:

A

Organisms are interdependent on one another for their survival, meaning if certain species are affected, this often has a knock-on effect upon the entire food web

58
Q

What are keystone species?

A

Species within a community that have a disproportionately large impact in an ecosystem (relative to their abundance). If a keystone species is removed, the ecosystem is often drastically changed

59
Q

Why are keystone species often predators?

A

As just a few predators can control the distribution and population of large numbers of prey species, preventing one species from becoming too dominant

60
Q

What is conservation?

A

The preservation and management of the environment and of natural resources

61
Q

What are the two main ways conservation is divided?

A

In situ conservation

Ex situ conservation

62
Q

What is in situ conservation?

A

Conservation that takes place within the natural habitat of the organism

63
Q

What is ex situ conservation?

A

Conservation that takes place outside of the natural habitat of the organism

64
Q

What are the 4 classifications of species that may need conservation?

A
  • Extinct
  • Extinct in the wild
  • Endangered
  • Vulnerable
65
Q

What does extinct mean?

A

There are no organisms of the species in the entire world

66
Q

What does extinct in the wild mean?

A

Organisms of the species are only present in captivity

67
Q

What does endangered mean?

A

A species in danger of extinction

68
Q

What does vulnerable mean?

A

A species that is considered likely to become endangered in the near future

69
Q

What is sustainable development?

A

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

70
Q

Why is in situ often better than ex situ conservation?

A

Allows interdependent relationships to be maintained
Allows the species to continue to adapt to their environment
Often cheaper

71
Q

What are examples of areas of in situ conservation?

A
  • Wildlife reserves

- Marine conservation zones

72
Q

How is poaching controlled?

A

Issuing fines/arresting poachers
Removal of desired product for poachers (e.g. removing rhino horn)
Banning access

73
Q

What is succession?

A

The natural process in which early colonising species are replaced over time, until a stable population is achieved- this can cause certain species to become extinct

74
Q

Give 2 in situ conservation techniques used

A

Controlling/culling of invasive species

Feeding the given species

75
Q

What are examples of ex situ institutions?

A
  • Botanic gardens
  • Gene banks
  • Captive breeding programs
76
Q

What do gene banks do?

A

They freeze genetic material, preserving the genes of many species of both animal and plant

77
Q

What do captive breeding programs do?

A

They produce offspring of species in a human controlled environment- they aim to create a healthy population size of a species, then reintroduce it into the wild

78
Q

Why may species born in captivity not be suitable for release?

A
  • Not resistant to local diseases
  • Behaviour necessary to survive not learnt
  • Destroyed habitat

A-Level OCR Biology (21 decks)

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