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

Chap 11 - Biodiversity Flashcards

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1
Q

What is a species?

A

a group of individual organisms with similar characteristics that can breed to produce fertile offspring

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2
Q

What is a habitat?

A

the natural home or environment of a species

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3
Q

What is biodiversity?

A

the variety of organisms/species present in an area

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4
Q

What are the types of biodiversity?

A

Genetic
Habitat
Species

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5
Q

Describe genetic biodiversity?

A

Variety of genes found in individuals in a species

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6
Q

Describe habitat biodiversity

A

the range of habitats in an area

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7
Q

Describe species biodiversity

A

species richness: # of species in an area
species evenness: number of individuals within a species in an area

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8
Q

Define population

A

all the organisms of a particular species found in an ecosystem

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9
Q

Define community

A

Populations of all species found in a particular ecosystem

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10
Q

Define ecosystem

A

system of organisms interacting with each other and the environment

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11
Q

Define abiotic/biotic

A

abiotic: non-living components (environmental)
biotic: living components

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12
Q

Define sampling

A

measurement of abundance and distribution of species in an area

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13
Q

Define random sampling

A

non-biased way of sampling where every individual has an equal likelihood of selection

allows estimation of population

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14
Q

Why is it important for samples to be random?

A

removes bias therefore making sample more reliable

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15
Q

What are the 3 types of non-random sampling?

A

Opportunistic
Stratified
Systematic

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16
Q

Describe stratified sampling

A

dividing populations into strata (sub-groups) based on characteristics

eg. male and female

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17
Q

Describe systematic sampling

A

used when there is a clear change in different areas of habitat using a line/belt transect

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18
Q

Describe opportunistic sampling

A

selecting organisms that are conveniently available to the experimenter

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19
Q

Describe kick-sampling

A

disturbing substrate in river banks to release organisms where they are captured downstream

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20
Q

Describe sweep netting

A

sweeping a net in long wild grass to catch flying invertebrates

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21
Q

Describe pitfall traps

A

a hole in soil deep to catch vertebrates covered to stop rainwater entering

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22
Q

Describe tree-beating

A

laying large cloth out and beating a tree to knock organisms and catch them in the cloth

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23
Q

Describe a pooter

A

glass container used to suck small organisms - filter covers one tube to stop organisms being sucked into mouth

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24
Q

Describe species evenness

A

the number of organisms within a species in an area

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25
Q

Describe species richness

A

the number of species present in an area

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26
Q

What are genetic causes for loss/gain of biodiversity?

A

+ mutations
+ interbreeding
- selective breeding
- captive breeding
- cloning
- genetic drift
- natural selection
- genetic bottleneck (catastrophic event)

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27
Q

Define abiotic factors

A

non-living components of an ecosystem
- temperature
- pH
- humidity
- light
- water

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28
Q

What is a frame quadrat?

A

square frame divided into a grid
- type and number of each species sampled

29
Q

What is a point quadrat?

A

frame containing horizontal bar - pins stick through the bar
- each species the pin touches is recorded

30
Q

What is a polymorphic allele?

A

gene with more than two possible alleles

31
Q

Define Locus

A

position of gene on a chromosome

32
Q

Why are seed banks effective in maintaining biodiversity?

A
  • seeds can be easily transported and stored
  • prevents extinction
  • preserves genetic material
33
Q

When would random sampling be appropriate?

A

when the population size is small or the size of the individual samples and their number are relatively small

34
Q

When would using systematic sampling be appropriate?

A

when a habitat is non-uniform and gradual changes occur

35
Q

Explain why greater genetic biodiversity increases a species’ chances for long-term survival

A
  • greater genetic biodiversity = more likely to adapt to environmental changes
  • some organisms likely to carry advantageous allele - carries through offspring
36
Q

Explain why it may not be possible to release some captively bred organisms back into the wild

A
  • no resistance to diseases
  • some behaviour is learned (eg. hunting)
  • habitats need to be reintroduced
37
Q

Explain what measuring species diversity tells us about the stability of an ecosystem

A
  • diversity often proportional to stability of ecosystem
  • so more stable = evenly distributed species
38
Q

Explain why the use of data loggers and sensors is advantageous.

A
  • reduces human error
  • detects rapid changes
  • high degree of precision
39
Q

Name 3 issues that affect biodiversity that are due to human population size

A
  • deforestation
  • climate change
  • agriculture
40
Q

Describe deforestation

A

permanent removal of large woodlands for housing, fuel and to create space

41
Q

Name two ways in which genetic biodiversity of a population can be increased.

A
  • mutation of DNA creating new alleles
  • interbreeding between populations transfer alleles
42
Q

What 4 ways can deforestation affect biodiversity?

A
  • can occur naturally
  • if only specific tree cut - species diversity reduced
  • habitat destruction reduces number of animal species present (food and shelter destroyed)
  • animals forced to migrate - biodiversity of other areas increases
43
Q

Name 5 methods associated with agriculture that affect biodiversity.

A
  • removal of hedgerows
  • pesticides - reduce species diversity
  • herbicides
  • monoculture
  • deforestation
44
Q

Describe monoculture and its impacts on biodiversity

A
  • producing only one crop lowers biodiversity directly
  • few animal species will be supported by one type of plant
45
Q

Describe 3 aesthetic reasons for maintaining biodiversity

A
  • presence of plants and animals enriches our lives
  • inspiration for musicians and artists
  • patients recover more rapidly from stress when supported by plants and natural environment
46
Q

What are 3 reasons for maintaining biodiversity

A
  • aesthetic
  • economic
  • ecological
47
Q

Describe 8 economic reasons for maintaining biodiversity

A
  • soil erosion and desertification reduces ability to grow crops - resource dependence on other nations
  • non-sustainable removal of resources will lead to collapse of industry in area
  • species with potential economic importance may become extinct before being discovered
  • continuous monoculture = soil depletion (red. in soil biodiversity) same land is reused - farmer reliant on expensive chemicals to maintain productivity
  • high biodiversity protects from abiotic stress and disease - change in conditions can destroy entire crops (irish famine)
  • high biodiversity = more tourism
  • greater diversity = potential to manufacture new products in future
  • plant varieties needed for cross-breeding = better characteristics
48
Q

Describe 2 ecological reasons for maintaining biodiversity

A
  • organisms interdependent - removal of one species has knock-on effect
  • removal of keystone species - ecosystem drastically changed and becomes unstable
49
Q

Define the term ‘keystone species’ and why it is important

A

keystone species: key role in maintaining structure of ecological community
- disproportionally large effect on environment compared to their abundance

50
Q

How is Simpson’s Index of Biodiversity calculated?

A

D = 1 - sum of (total # organisms in species/total number of species)^2

51
Q

What is the formula for genetic biodiversity?

A

proportion of polymorphic gene loci = # polymorphic gene loci / total # loci

52
Q

What are the implications of a habitat having high biodiversity?

A
  • large # of successful species
  • wide range of adaptions to environment
  • complex food webs
  • small effects when environment changes
53
Q

What are the implications of a habitat with a low biodiversity?

A
  • few successful species
  • specific adaptions to environment
  • simple food webs
  • major effects when environment changes
54
Q

Why is it important to monitor genetic biodiversity?

A

to monitor health of population and ensure long term survival

55
Q

Define in-situ conservation

A

conservation within natural habitat

56
Q

Define ex-situ conservation

A

conservation out of natural habitat

57
Q

Name 2 methods of in situ conservation

A
  • wildlife reserves
  • marine conservation zones
58
Q

Name 3 methods of ex situ conservation

A
  • botanic gardens
  • seed banks
  • captive breeding programmes
59
Q

Describe the role of botanic gardens in maintaining biodiversity.

A

species are actively managed & provided with resources to grow (soil nutrients, watering, removal of pests)

60
Q

Describe the role of seed banks in maintaining biodiversity.

A

seeds stored so that new plants can be grown in the future - extinction prevented
- easy to transport
- stored easily

61
Q

Explain how seed banks store the seeds and why these methods are important.

A
  • seeds are dried and stored at temperatures of -20C
  • slows rate at which they lose ability to germinate
62
Q

Describe how captive breeding programmes reduce genetic biodiveristy.

A
  • small number of captive individuals available for breeding
  • there is no gene flow
63
Q

Explain the aim of captive breeding programmes in maintaining genetic biodiversity.

A

aim to create a stable, healthy population of a species and gradually reintroduce it back to natural habitat

64
Q

Describe 7 methods of active management in wildlife reserves.

A
  • controlling grazing - only for certain amount of time, allowing area of land species to recover
  • restricting human access - providing paths so plants aren’t trampled
  • controlling poaching
  • feeding animals - ensure more organisms survive to reproductive age
  • reintroduction of species - adding species to areas that have become locally extinct
  • culling or removal of invasive species - removal of competition for native species
  • halting succession - only way of preventing areas such as moorland from becoming woodland is grazing
65
Q

Describe the role of marine conservation zones in maintaining biodiversity.

A

creates areas of refuge from which populations can build up and repopulate areas

66
Q

Describe 3 ways in which zoos can contribute to conservation.

A
  • provide animals shelter, abundant supply of food, absence of predators and vet treatment
  • genealogical data is kept on individuals so when bred, they choose the pairs that will maximise genetic biodiversity
  • money earned can be used as funding for researching new methods of conservation
67
Q

State the full name of CITES and explain how it helps protect biodiversity.

A

Convention on International Trade in Endangered Species

  • regulates international trade of wild plant and animal specimens and their products
  • protects species from over-exploitation that could endanger them
68
Q

State 3 outcomes from the Rio convention.

A

Convention on Biological Diversity (CBD)

  • requires countries to develop national strategies for sustainable development
  • agreement to stabilise greenhouse gas concentration in atmosphere
  • prevent transformation of fertile land into desert
69
Q

What does conservation mean?

A

maintenance of biodiversity through human action/management - managing ecosystems so resources can be used without running out

OCR A-Level Biology (16 decks)

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