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Yr 12 Biology A Level > Biodiversity > Flashcards

Biodiversity Flashcards

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1
Q

What is biodiversity?

A

The variety of species in an area.
The variety of genes in a population.

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2
Q

Define habitat

A

The environment in which a species usually lives

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3
Q

Define community

A

All the populations of living organisms in a particular habitat.

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4
Q

Define species richness

A

Number of species living in a particular area

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5
Q

Define species evenness

A

Number of individuals of each species living in a community

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6
Q

What does species evenness indicate?

A

Higher species evenness indicates higher biodiversity.
Low species evenness indicates dominance by only a few species.

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7
Q

Explain the importance of sampling in measuring the biodiversity of a habitat

A
  • It is difficult to count every individual.
  • Sample provides an estimate
  • Representative of whole area
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8
Q

Outline how to perform unbiased, random sampling with a quadrat

A
  • Mark a grid in the area to be sampled using measuring tapes.
  • Use a random number generator to provide coordinates on the grid.
  • Place quadrat at coordinates and count species/organisms within a species.
  • Determine abundance e.g. percentage frequency or percentage cover
  • Repeat many times
  • Calculate mean
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9
Q

Determine methods of non-random sampling

A

Opportunity

  • Use organisms that are conveniently available
  • May not be representative of the population

Stratified

  • Population divided into subgroups
  • Random sample taken from each subgroup proportional to its size

Systematic

  • Different areas in habitat identified
  • Each area sampled e.g. belt transect
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10
Q

Outline how to perform unbiased sampling with a transect

A
  • Set up transect along area to be sampled
  • Place quadrat at regular intervals and count species / organisms within a species
  • Determine abundance e.g. percentage frequency or percentage cover
  • Repeat many times
  • Calculate mean
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11
Q

How can representative samples be obtained when sampling?

A
  • Unbiased method of selecting sample area e.g. random number generator
  • Sample many times and calculate mean
  • Standardised sampling procedure e.g. size of net, only count organisms completely in quadrat
  • Use identification key
  • Sample at different times/seasons.
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12
Q

Simpson’s diversity index equation

A

D = 1 - (n/N2)

n = number of individuals of a particular species

N = total number of individuals of all species

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13
Q

Outline the significance of a high value of Simpson’s Index of Diversity

A
  • Many species present (high species richness)
  • All species evenly represented (high species evenness)
  • High biodiversity - More robust habitat
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14
Q

Outline the significance of a low value of Simpson’s Index of Diveristy

A
  • Habitat dominated by only a few species
  • Habitat is unstable
  • Less likely to cope with change
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15
Q

Define genetic biodiverity

A

Differences in alleles within a population of a species

More alleles present = more genetically biodiverse

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16
Q

Explain the importance of genetic biodiversity

A
  • Greater genetic biodiversity = more likely to adapt to changes in environment
  • Less likely to become extinct
  • Likely to be some organisms with advantageous alleles
  • These organisms more likely to survive and reproduce
  • Advantageous alleles passed onto next generation
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17
Q

What factors increase genetic biodiverity?

A
  • Mutations in DNA create new alleles
  • Interbreeding between populations increases gene flow
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18
Q

What factors decrease genetic biodiversity?

A
  • Genetic bottlenecks - major event leads to only few individuals surviving - leads to small gene pool
  • Selective breeding
  • Natural selection - less advantageous alleles lost
  • Captive breeding e.g. zoos
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19
Q

Define polymorphic gene

A

A gene with more than one allele e.g. human blood groups

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20
Q

Define monomorphic gene

A

A gene with only one allele - most genes are monomorphic genes

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21
Q

Define loci

A

The position of a gene on a chromosome

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22
Q

How is genetic biodiversity measured?

A
  • Using the proportion of polymorphic gene loci in a population
  • The greater the proportion, the greater the genetic biodiversity
23
Q

How is the proportion of polymorphic gene loci in a population calculated?

A

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

24
Q

Why is human impact on biodiversity increasing?

A
  • Population rapidly increasing
  • Require more food, housing, resources etc
25
Q

List human activities that can reduce biodiversity

A
  • Deforestation
  • Agriculture
  • Pollution (climate change)
26
Q

Explain how deforestation can reduce biodiversity

A
  • Reduces number of trees
  • Reduces species diversity
  • Destroys animal habitat
27
Q

Explain how agriculture can reduce biodiversity

A
  • Removal of hedgerows destroys habitats and reduces prey for birds
  • Monocultures reduce species diversity
  • Removal of meadows reduces species diversity and habitats
  • Pesticides and herbicides reduces species diversity
28
Q

Explain how climate change could reduce biodiversity

A
  • Global warming is melting polar ice caps - Could lead to extinction of species living in polar regions - Changes migration pattern of Arctic animals
  • Rising sea levels could flood low lying land - Reduces terrestrial habitats - Salt water could reduce fresh water habitats in rivers
  • Higher temperatures and less rainfall - Reduction in plant species - Xerophytes becoming more dominant - Impact on food chains
  • Insect life cycles will change - Key pollinators of many plants - Could lead to extinction of plants - Greater spread of tropical diseases
29
Q

Suggest how the excessive use of inorganic fertilisers can cause a reduction in biodiversity

A
  • Fertiliser promotes growth of a few plant species
  • Other plant species out-competed
  • Leads to disruption of food chains
  • Reduction in soil quality over time so plants cannot grow
30
Q

Explain why a reduction in biodiversity may present problems for agriculture in the future

A
  • Loss of genetic diversity in wild population
  • Environmental requirements may change in future
  • Lost alleles may have been useful to withstand change
31
Q

Define keystone species

A
  • Species that are essential for maintaining biodiversity
  • Has disproportionately large effect on their environment relative to their abundance
32
Q

Explain why keystone species are often predators

A
  • Predators keep populations of prey at a consistent level
  • Allows for balanced coexistence of other species
33
Q

Why is it important to maintain biodiversity?

A
  • Maintains complex, stable food chains
  • Maintains variety of habitats for other organisms
  • Ensures keystone species are not removed - avoids drastically changing habitat
  • Aesthetic reasons e.g. natural beauty
  • Economic reasons e.g. tourism
  • Provides natural resources e.g. wood, medicine
34
Q

Define in situ conservation

A

In natural habitat

35
Q

Define ex situ conservation

A

Not in natural habitat

e.g. zoos, botanical gardens, seed banks

36
Q

Define preservation

A

Protection of an area by restricting or banning human use

37
Q

Give the benefits of in situ conservation in wildlife reserves

A
  • Controlled grazing allows plant species to recover
  • Human access restricted e.g. paths to prevent trampling of plants
  • Control poaching of animals
  • Reintroduction of species
  • Removal of invasive species - ensure native species able to access resources
38
Q

Give the benefits of in situ conservation in marine conservation zones

A
  • Preserves species-rich areas e.g. coral reefs
  • Control fishing areas and methods
39
Q

What are the difficulties of setting up marine conservation zones?

A
  • Large areas of sea required as aquatic species often move large distances
  • Economic impact on fishermen
40
Q

Explain why it is sometimes necessary to conserve a plant species outside of its natural habitat (et situ)

A
  • Natural habitat lost due to climate change/human activity
  • Number of plants in natural habitat is very low
  • Reproduction is difficult in wild if numbers are low
  • Breeding ex situ can maintain the gene pool
  • Allows protection from grazers, plant collectors or competing species
  • Protection from disease
41
Q

What is the purpose of a seed bank?

A
  • A store of plant genetic material
  • Seeds dried and stored at cold temperatures to maintain viability
  • Provides back-up against extinction
42
Q

Why should the seeds of the same species in a seed bank be collected from several different sites in the wild?

A
  • Maintains genetic variation in gene pool
  • Reduces chance of future disease affecting the whole population
  • Reduces chance of inbreeding
  • Maintains geographical variation
43
Q

Give advantages of conserving plant species as seeds and not as adult plants

A
  • Can be collected with minimal damage to wild population
  • Take up little space
  • Can store greater genetic diversity
  • Low maintenance costs
  • Easier and cheaper to transport
  • Remain viable for long periods
  • Prevents fertilisation by undesired pollen
44
Q

Explain why some species are conserved in captivity (ex situ) rather than in the wild (in situ)

A
  • Protection from diseases or poisons
  • Health of individuals monitored
  • Reduced mortality of young
  • Provision of mates
  • Protection from hunting and predation
  • Competition reduced between individuals and species
45
Q

Why may organisms born in captivity not be suitable for release into the wild?

A
  • May be loss of resistance to diseases present in wild
  • Behaviour vital for survival in wild may not have been learnt
  • Natural habitat may no longer be large enough to take more individuals
46
Q

Discuss the advantages of captive breeding programs

A
  • Maintains or increases endangered populations
  • Allows for reintegration of species into its habitat
47
Q

Discuss disadvantages of captive breeding programs

A
  • Leads to loss of genetic diversity
  • Leads to organisms not learning behaviours of their wild counterparts
  • Genetic problems can occur in offspring due to inbreeding
  • Can decrease the disease resistance of a population
48
Q

State what CITES stands for

A
  • Convention on International Trade in Endangered Species
49
Q

What are the aims of CITES?

A
  • Conservation of biodiversity
  • Regulate trade of endangered species
  • Ensure trade does not endanger wild populations
50
Q

What are the aims of the Rio Convention on Biological Diversity?

A
  • Sustainable use of organisms and habitats
  • Share access to scientific knowledge and technology
  • Promote international cooperation on biodiversity issues
  • Promote ex situ conservation methods
51
Q

What are the aims of the Countryside Stewardship Scheme?

A
  • Sustain beauty and diversity of the landscape
  • Improve, extend and create wildlife habitats
  • Restore neglected land
  • Improve opportunities for countryside enjoyment
52
Q

Explain why local and international agreements can help preserve biodiversity

A
  • Landowners have economic reasons for exploiting natural resources
  • Exploitation leads to loss of biodiversity
  • Financial incentives needed to replace income from exploiting a resource
  • Animals do nor respect nation’s boundaries
  • To preserve number of species in natural habitat
53
Q

Define sustainable development

A

Economic development that meets the needs of the people today.

Without limiting future generations’ ability to meet their needs.

Yr 12 Biology A Level (15 decks)

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