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A-Level Biology🌼 > Topic 4: Biodiversity > Flashcards

Topic 4: Biodiversity Flashcards

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1
Q

Biodiversity definition

A

Biodiversity = the variety of living organisms in an area

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2
Q

Habitat Biodiversity

A

Habitat biodiversity = number of different habitats in an area

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3
Q

Species biodiversity

A

Species biodiversity = the number of different species and their abundance in an area

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4
Q

Genetic biodiversity

A

Genetic biodiversity the number of different alleles within a species or population

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5
Q

Importance of biodiversity

A

Biodiversity is important in maintaining the balanced ecosystem for all organisms as all species are interconnected (they rely on eachother)

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6
Q

Levels of which biodiversity can be studied

A

Levels of which biodiversity can be studied:
-Habitat biodiversity
-Species biodiversity
-Genetic biodiversity

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7
Q

Why is it important to measure biodiversity?

A

Measuring biodiversity is important in conservation as it informs scientists of the species that are present in an area to give a degree of biodiversity

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8
Q

Two components of species biodiversity

A

Two components of species biodiversity:
-Species richness = the number of different species in a habitat
-Species evenness = the number of individuals within each species

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9
Q

Community definition

A

Community = all the populations of living organisms in a particular habitat

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10
Q

Result of a greater genetic biodiversity

A

A greater genetic biodiversity within a species 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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11
Q

Issues that come with measuring biodiversity

A

Issues:
-Not all species have been found on earth
-New species are being found all the time
-Evolution and speciation are occuring
-Species are becoming extinct
-The estimates do not consider the number of individuals of each species or the variation within a species

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12
Q

How do you ensure the sample of an area if valid and representative?

A

Random sampling technique ensures samples are valid and representative.

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13
Q

What is species richness?

A

Species richness is the number of different species in a habitat

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14
Q

How to calculate species evenness

A

Calculate species evenness by comparing the total number of each organism present - populations of plants/animals that are similar in size or density represent an even community

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15
Q

Types of sampling

A

Types of sampling include:
Random sampling
Non-random sampling
Stratified
Systematic

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16
Q

Random sampling

A

Random sampling refers to selecting individuals by chance eg random number tables or computers.

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17
Q

Non-random sampling

A

Non-random sampling is where it’s not chosen at random, and can be divides into three techniques:
-Opportunistic
-Stratified
-Systematic

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18
Q

Opportunistic sampling

A

Opportunistic sampling - weakest sampling - may be unrepresentative - uses organisms that are conveniently available

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19
Q

Stratified sampling

A

Stratified sampling - dividing populations into a number of strata (sub-groups) based on a particular characteristic - eg males and females - random sample then taken from each strata

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20
Q

Systematic sampling

A

Systematic sampling - different areas within a habitat identified and sampled seperately - often carried out with transects - line or belt transect

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21
Q

Reliability of sampling

A

Reliability of sampling:
-Sampling bias - biased selection process - can be reduced with random sampling
-Chance - by chance organism is not representative - effect can be minimized by using a large sample size as it lowers the probability of chance affecting the results

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22
Q

Techniques used for sampling animals

A

Techniques used for sampling animals:
-Pooter
-Sweep nets
-Pitfall traps
-Tree beating
-Kick sampling

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23
Q

Pooters

A

Pooters:
-For small insects
-Sucking on a mouthpiece to draw up insects into the holding chamber via the inlet tube
-Filter prevents them from being sucked into the mouth

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24
Q

Sweep nets

A

Sweep nets are used to catch insects in areas of long grass

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25
Q

Pitfall traps

A

Pitfall traps:
-Catches small, crawling invertebrates
-Hole is dug in the ground which insects fall into
-Deep enough so that they cannot crawl out with a roof structure so they do not fill with rainwater

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26
Q

Tree beating

A

Tree beating:
-Used to take samples if invertebrates living in trees or bushes
-Large white cloth is stretched out under a tree
-Tree shaken or beaten to dislodge invertebrates

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27
Q

Kick sampling

A

Kick sampling
-Used to take samples of organisms living in rivers
-Riverbank and bed is kicked for a period of time to disrupt the substrate
-Net held downstream for a set period of time to capture any organism in the flowing water

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28
Q

Why is it difficult to estimate population size of organisms?

A

Estimating population size is difficult due to organisms constantly moving or hiding

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29
Q

How to estimate population size?

A

Population size can be estimated using the capture-recapture method

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30
Q

Capture-mark-release-recapture method for estimating population size

A

Capture-mark-release-recapture method for estimating population size:
-Capture as many individuals of species in an area as possible
-Mark organisms
-Release back into environment
-Recapture and compare number of marked indivudals with number of unmarked individuals

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31
Q

Types of quadrats

A

Types of quadrats:
Point quadrat
Frame quadrat

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32
Q

Point quadrats

A

Point quadrats:
-Frame containing horizontol bar
-At set intervals along bar, long pins pushed through bar to reach the ground
-Each species of plant the pin touches is recorded

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33
Q

Frame quadrats

A

Frame quadrats:
-Square frame divided into a grid of equal sections
-Type and number of species of quadrat is recorded
-Random sampling should be used
-Can be used alongside a line or belt transect

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34
Q

How to measure species richness?

A

Measuring species richness:
-Compile list of each species identified
-Total number of species calculated
-Identification keys used to accurately identify species

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35
Q

How to measure species evenness?

A

Measuring species evenness:
-How close in numbers the population of each species in an environment are

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36
Q

Calculating population density of species evenness

A

Density:
-Use a frame quadrat
-Count number of individual large plants
-Absolute measure (not estimate)

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37
Q

Measuring frequency of species evenness

A

Frequency:
-Used where individual members of a species are hard to count (eg grass or moss)
-Count number of squares a particular species is present in

38
Q

Calculating percentage cover of species evenness

A

Percentage cover:
-Used for speed
-An estimate by eye of the area within a quadrat that a particular plant species covers

39
Q

Advantages of the different ways of measuring species evenness

A

Advantages of the different ways of measuring species evenness:
-Population density: accurate
-Frequency: rapid, can be used when individual members of species can be identified
-Percentage cover: lots of data can be collected quickly

40
Q

Disadvantages of the different ways of measuring species evenness

A

Disadvantages of the different ways of measuring species evenness:
-Population density: Time consuming
-Frequency: only approximate result
-Percentage cover: only approximate result

41
Q

Advantages of using a temperature probe rather than a thermometer

A

Advantages of using a temperature probe rather than a thermometer:
-Less chance of human error
-Can measure rapid changes of temperature
-Can be stored on a computer

42
Q

Importance of sampling in measuring the biodiversity of a habitat

A

Importance of sampling in measuring the biodiversity of a habitat:
-Sampling is quicker, and more representative

43
Q

Difference between species richness and evenness and why are they both needed to assess biodiversity?

A

-Species richness -> number of species in a habitat
-Species evenness -> number of individuals of species in a habitat
-High levels of species richness and evenness indicate high levels of biodiversity
-Both needed to reveal dominance of species

44
Q

Significance of a low value of simpson’s index of diversity

A

Significance of a low value of simpson’s index of diversity:
-Dominated by one/few species
-Ecosystem is therefore unstable and unlikely to cope with change

45
Q

Sampling strategy that should be used when finding biodiversity of different areas within an ecosystem

A

Sampling strategy that should be used when finding biodiversity of different areas within an ecosystem:
-Random stratified sampling
-Idea that number of sampling that should be taken within each area should be proportional to their size (eg 8 samples for an 800m area, and 24 for a 2400m area)

46
Q

How to measure the frequency of organisms within a sample

A

Frequency:
-Count organisms
-Divide that by the area surveyed

47
Q

Simpson’s index of diversity

A

Simpson’s index of diversity = measure of the relationship between the number of different species in a habitat (species richness) and the number of individuals within each species (species evenness).
-Higher the value = higher the biodiversity

48
Q

Why is biodiversity important?

A

Biodiversity is important due to interdependance of species

49
Q

What do the value indicate in the Simpsons Index of Diversity?

A

Simpsons index of university:
-Always a value between 0 and 1
-0 = no diversity
-1 = infinite biodiversity
-The higher the value, higher the biodiversity
-Indication of species richness - high value, high species richness

50
Q

What habitat features are associated with low biodiversity?

A

Habitat features associated with low biodiversity:
-Few number of successful species
-Stressful and/or extreme with relatively few ecological niches
-Few species live in habitat, often with very specific adaptations to the environment
-Simple food webs
-Major effects on the ecosystem when there is a change to the ecosystem

51
Q

What features are associated with habitats that have a high biodiversity?

A

Features associated with habitats of a high biodiversity:
-Large number of successful species
-Benign/not stressful nature of environment, more ecological niches
-Many species, with few adaptations to the environment
-Small effect on ecosystem when there is a change

52
Q

Uses of sampling

A

Uses of sampling:
can estimate abundance (without having to count them all) and can measure a particular characteristic (mean height of plants for example)

53
Q

Belt transects

A

Belt transects: Two parallel lines are marked along the ground and samples are taken of the area at specified points

54
Q

High genetic biodiversity

A

High genetic biodiversity:
More alleles, more likely to have advantageous characteristics, more likely to adapt to changes in the environment, hence are less likely to become extinct

55
Q

Reasons why sampling is carried out

A

Reasons why sampling is carried out:
-To reduce time needed to collect/count organisms
-To minimise costs
-Some organisms within a habitat are not easily located

56
Q

Advantages of random sampling

A

Advantages of random sampling: no bias, more representative, all organisms have an equal chance to be selected

57
Q

Advantages of non-random sampling

A

Advantages of non-random sampling:
-Allows for easier comparison between abiotic factors
-Easier to conduct and cheaper, and faster

58
Q

How to sample an area of grassland

A

Sampling an area of grassland:
-Use of random sampling to reduce bias
-Use of quadrats for plant species
-Use of sweep nets for flying insects
-Calculate species richness and evenness
-Obtain an average from the data to estimate the population size

59
Q

Reasons for conservation of plant species eg trees

A

Reasons for conservation of plant species eg trees:
-Aesthetic value
-Potential source of medicine
-Maintaining habitats for species

60
Q

Situ and ex-situ meaning

A

Situ: In it’s natural/original place
Ex-situ: Not in it’s natural/original place

61
Q

Advantages of using seed banks rather than just using adult seeds as a means to conserve an endangered species

A

Advantages of using seed banks rather than just using adult seeds as a means to conserve an endangered species:
-Most plants will produce excess (so) can be collected from wild without damaging the wild
-Takes up little space
-Able to store more/larger species
-Longer viability

62
Q

Why are seeds in a seedbank taken from different areas?

A

Seeds in a seedbank is taken from different areas because:
-To maintain genetic biodiversity
-Reduced chance of further disease
-Maintain geographical variation

63
Q

Meaning of a low simpsons index

A

Low simpsons index:
-Low biodiversity
-Chance of an area being dominated by one/few species -> affects the whole habitat -> community will be unable to withstand change

64
Q

How to ensure an accurate simpsons index value:

A

How to ensure an accurate simpsons index value:
-Use of random sampling
-Sample at different times of the year

65
Q

Benefit of index of diversity

A

The benefit of using the index of diversity instead of just species richness is that it takes into account the population sizes of different species in one community.

66
Q

Genetic biodiversity calculation

A

Genetic diversity =
total number of loci/
number of polymorphic gene loci
​
x 100

67
Q

Importance of genetic biodiversity

A

Importance of genetic biodiversity:
-Essential to the survival of a species
-Helps monitor the health of the population and ensure its long-term survival

68
Q

Genetic biodiversity

A

Genetic biodiversity:
-All members in a species have the same genes
-Members may have different alleles of these genes
-The differences in alleles creates genetic biodiversity
-The more alleles present, the more genetically biodiverse the population

69
Q

Benefits of genetic biodiversity

A

Benefits of genetic biodiversity:
-Likely to be an advantageous allele
-Likely to be able to adapt to changes in their environment
-Less likely to become extinct

70
Q

Factors that affect genetic biodiversity

A

Factors that affect genetic biodiversity:
-Mutation (creating a new allele)
-Interbreeding (when an individual migrates from one population and breeds with another member, alleles are transferred - known as gene flow)
-Selective breeding
-Captive breeding programmes
-Rare breeds
-Artificial cloning
-Natural selection
-Genetic bottlenecks
-Founder effect
-Genetic drift

71
Q

Selective breeding affect on genetic biodiversity

A

Selective breeding:
-Few individuals are selected for their advantageous characteristics
-Allele frequency decreases as advantageous allele increases

72
Q

Captive breeding affect on genetic biodiversity

A

Captive breeding:
-Small number of captive individuals of a species are available for breeding
-Small number of allele frequency due to small number of individuals within a population

73
Q

Rare breeds affect on genetic biodiversity

A

Rare breeds:
-Selective breeding may have been used historically to produce a breed of domestic animal or plant which has become less popular or unfashionable
-Small number of breeds remain and therefore low frequency of alleles

74
Q

Artificial cloning affect on genetic biodiversity

A

Artificial cloning:
-Using cuttings to clone a farmed plant
-Only alleles from the clone are passed to offspring
-Reduces allele frequency

75
Q

Natural selection affect on genetic biodiversity

A

Natural selection:
-Species evolve to contain the alleles for advantageous characteristics
-Alleles coding for less advantageous characteristics will be lost from the population

76
Q

Genetic bottlenecks affect on genetic biodiversity

A

Genetic bottlenecks affect on genetic biodiversity:
-Few individuals within a population survive an event of change eg disease, habitat destruction, etc
-Reduces gene pool
-Only alleles of surviving members are available to be passed on

77
Q

Founder effect on genetic biodiversity

A

Founder effect:
-Small number of individuals create a new colony, geographically isolated from the original
-Gene pool for the new population is small

78
Q

Genetic drift affect on genetic biodiversity

A

Genetic drift:
-Due to random nature of alleles being passed on frmo parents to their offspring the frequency of occurrence of an allele will vary
-In some cases, the existence of a particular allele can disappear from a population
-More pronounced in populations with a low genetic biodiversity

79
Q

How to measure genetic biodiversity

A

How to measure genetic biodiversity:
-By measuring polymorphism
-Polymorphic genes have more than one allele
-Eg:
I^A- resulting in antigen A production
I^B- resulting in antigen B production

80
Q

Monomorphic genes

A

Monomorphic genes - genes with one single allele - this ensures that the basic structure of individuals within a species remain consistent

81
Q

Measuring genetic biodiversity equation (proportion of polymorphic gene loci)

A

-Proportion of polymorphic gene loci = (number of polymorphic gene loci) / (total number of loci)

-Locus = the position of the gene on a chromosome
-The greater the proportion of polymorphic gene loci, the greater the biodiversity within the population

82
Q

Factors affecting biodiversity

A

Factors affecting biodiversity:
-Deforestation
-Agriculture
-Climate change

83
Q

Human influence on biodiversity

A

Human influence:
-Human population growing dramatically
-Due to improvements in medicine, hygiene, housing and infrastructure
-Ecology is being disrupted as a result of this increasing population

84
Q

Deforestation affect on biodiversity

A

-Reduces species biodiversity if only one type of tree is felled
-Reduced number of animal species in an area due to habitat, food source and home loss
-Animals are forced to migrate to other areas to ensure survival (surrounding areas may have increased biodiversity)

85
Q

Agriculture affect on biodiversity

A

Agriculture:
-Removal of hedgerows: reduces number of plant species present and destroys habitat of animals
-Uses of chemicals (pesticides, herbicides) - reduces species diversity directly as it destroyes the pest species and indirectly destroyes the food source of other organisms
-Monoculture - lowers biodiversity as only one species is present

86
Q

Climate change affect on biodiversity

A

Climate change:
-Melting of polar ice caps - extinction of species in these areas
-Rising sea levels from melting ice caps - reduces available terrestrial habitats and salt water flows further up rivers and reduces habitats of freshwater plants and animals
-High temps and less rainfall - some plants species unable to survive - loss of animals due to loss of food source
-Insect life cycles and populations will change - key pollinators of many plants

87
Q

Reasons for maintaining biodiversity

A

Reasons for maintaining biodiversity:
-Aesthetic
-Economic
-Ecological

88
Q

Aesthetic as a reason for maintaining biodiversity

A

Aesthetic as a reason for maintaining biodiversity:
-Prescence of different plants animals enriches our lives
-Provides inspiration for people such as musicians and writers
-Studies show that patients recover more rapidly from stress and injury when they are supported by plants and in a relatively natural environment

89
Q

Economy as a reason for maintaining biodiversity

A

Economy as a reason for maintaining biodiversity:
-Soil erosion can occur as a result of deforestation which reduces ability to grow crops and feed people so it must be maintained (resource dependant on other countries)
-Important to conserve organisms that we use to make things eg hardwood timber
-Large-scale habitat and biodiversity lsoses means that species with potential economic importance may become extinct before they are even discovered
-Continuous monoculture + reliance on pesticides and fertilisers results in soil depletion ecosystem
-High biodiversity provides protection against abiotic stresses and disease
-Tourism

90
Q

Ecology as a reason for maintaining biodiversity

A

Ecology as a reason for maintaining biodiversity:
-All organisms are interdependant on others for survival
-Some species play key role in maintainig structure of an ecological community - keystone species

91
Q

Economic benefit of a high biodiversity

A

Economic benefit of a high biodiversity:
-High plant biodiversity supports drug discovery and development
-Tourism industry brings economic benefits

92
Q

Importance of sampling in measuring the biodiversity of a habitat

A

Importance of sampling in measuring the biodiversity of a habitat:
-Quick method of measuring population size
-Provides an estimate
-Impossible to count every individual

A-Level Biology🌼 (25 decks)

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