A-level Biology > 4.2.1 - Biodiversity > Flashcards

4.2.1 - Biodiversity Flashcards

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1
Q

Define the term ‘Biodiversity’ ?

A

Biodiversity - The variety of living organism present in an area

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2
Q

What are the different levels at which biodiversity can be studied ?

A
  • Ecosystem/Habitat biodiversity
  • Species biodiversity
  • Genetic biodiversity
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3
Q

Define the term ‘Ecosystem/Habitat biodiversity’ ?

A

Ecosystem/Habitat biodiversity : The range of different ecosystems/ habitats within a particular area

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4
Q

Explain habitat biodiversity and name examples ?

A
  • Each habitat provides conditions which can support a number of different species
  • Therefore, the greater the habitat biodiversity, the greater the species biodiversity within an area
  • eg. sand dunes, streams, meadow and woodland
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5
Q

Define ‘species diversity’ ?

A

Species diversity : The number of different species and individuals within each species in a community

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6
Q

Define the term ‘Species richness’ ?

A

Species richness - The number of different species in a particular area

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7
Q

Define the term ‘Species evenness’ ?

A

Species evenness - The relative abundance of different species within the community

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8
Q

Define the term ‘Community’ ?

A

Community - All the populations of different species int eh same area at the same time

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9
Q

Define the term ‘Genetic biodiversity’ ?

A

Genetic biodiversity : The variety of genes among individuals in a population of one species

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10
Q

What are the benefits of genetic biodiversity ?

A
  • Allows species to adapt to and survive changes in their environment
  • Provides variation for natural selection
  • Can offer camouflage/ protection from predators
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11
Q

Explain how small/ isolated populations affect genetic biodiversity ?

A
  • Genetic variation/ biodiversity will increase
  • This will result in a small gene pool/ few alleles
  • Homozygosity increases/ heterozygosity decreases
  • Closely related individuals in the species will mate/ inbreeding
  • Lower genetic diversity results in low potential for adaptation to changing environment / susceptible to disease
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12
Q

Define the term ‘Abundance’ ?

A

Abundance -The amount of organisms are present within a habitat

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13
Q

Define the term ‘Distribution’ ?

A

Distribution - Where organisms live within a habitat

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14
Q

Define the term ‘Sampling’ ?

A

Sampling - Taking measurements of a limited number of individual organisms present in a particular area

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15
Q

What are the two types of sampling ?

A
  • Random
  • Non-random
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16
Q

What is the difference between random and non-random sampling ?

A
  • During random sampling, samples are chosen randomly
  • During non-random sampling, the sample is not chosen at random
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17
Q

Explain how random sampling is carried out ?

A
  • Lay out two tape measures at right angles to each other to create grid area
  • A random number generator is used to generate two random numbers that serve as coordinates on grid
  • Place quadrant at the coordinates and take your sample
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18
Q

When is random sampling appropriate ?

A

When a sampling area is reasonably uniform or has no clear pattern of species distribution

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19
Q

What are the different types of non-random sampling ?

A
  • Opportunistic sampling
  • Stratified sampling
  • Systematic sampling
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20
Q

Explain what is opportunistic sampling ?

A
  • Sampling is carried out on the basis of opportunity ( e.g. sample sites that can be reached quickly and safely are chosen )
  • May not be representative of population and involve bias
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21
Q

Explain what is stratified sampling ?

A

The number of random samples taken within each habitat type is proportional to the area covered by each habitat type

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22
Q

Explain what is systematic sampling ?

A

Samples are taken across a habitat with reference to the change in distribution of species within the habitat

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23
Q

What factors affect the reliability of a sample ?

A
  • Sampling bias
  • Chance
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24
Q

Explain how sampling bias affects the reliability of a sample ?

A
  • The selection process may be biased by accident or deliberately, decreasing accuracy
  • Effect reduced by using random sampling where human choosing of sample is reduced
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25
Explain how chance affects the reliability of a sample ?
- Organisms selected may by chance not be representative of the whole population - Effect reduced by using large sample size and carrying out statistical test
26
How to improvise accuracy of experiment involving sampling ?
- Take a large sample, allowing you calculate mean and carry out statistical test to measure significance - Repeat the experiment/ investigation again - Randomly sample to avoid bias
27
What are the different sampling techniques for animals ?
- A pooter - Sweep nets - Pitfall traps - Tree beating - Kick sampling
28
What are the different sampling techniques for plants ?
- Frame quadrant - Point quadrant - Line transect - Belt transect
29
Explain when and how a pitfall traps are used to take samples ?
- Used for ground-dwelling invertebrates - Dig hole and place container in soil - Make top of container level with the ground - Leave it overnight - Identify / count invertebrates - Sample both areas randomly ( at 5+ sites )
30
Explain how you would carry out kick sampling to take sampling ?
- One person would gently kick the river bed to distrust eh earth and the organisms within it - A second person stands behind them with a net to capture organisms released
31
Explain when and how a pooter is used to take samples ?
- Used to suck up small invertebrates - The first tube is placed over the insect and the second tube is used to create suction - Once inside the container the sampled organisms can be easily viewed and identified
32
Explain what is a frame quadrant and how is it used ?
- Used to sample plants and slow-moving organisms - A square frame of a known size, typically 0.5 x 0.5 m
33
What is a point quadrant ?
- A horizontal bar with holes along it at set intervals that long pins can be placed through - The pin ism used through to touch the ground, any species touching the pin are recorded
34
What are the different methods used to record species present using quadrant ?
- Density - Frequency - Percentage cover
35
How are species recorded using density, frequency and percentage cover ?
- Density : The number of individuals present - Frequency : The number of squares your species is present in ( eg. in 25 out of 100, 25 % frequency ) - Percentage cover : Estimate the percentage of the entire quadratic covered with species
36
How can calculating percentage cover be improved ?
- By standardising how the percentage is estimated - eg. A square counts as 1% if at least half the sauce is covered by species
37
What is a transect ?
A line along which samples can be taken
38
Explain how to use a line transect ?
- Lay out a measuring tape in a straight line across the sample area - At regular distances along the tape, e.g. every 1 m, record the identity of the organisms that touch the line
39
Explain how to use a belt transect ?
- Lay out a measuring tape in a straight line across the sample area - Place quadrats at regular intervals, or continuously, along the tape and record the abundance or percentage cover of each species within each quadrat
40
How to determine what area has a species richness and species evenness ?
- Area A/B has a greater species richness since is has X more different types of species - Area A/B has a greater species evenness as range of number of individual is smaller
41
How is an animal population within an area estimated ?
By using the capture-mark-release-recapture technique
42
What is the equation for the capture-mark-release-recapture technique ?
Estimate of population = ( size of first sample x size of second sample ) / number of recaptured individuals
43
Define the term 'Abiotic factors' ?
Abiotic factor - The non-living conditions within an ecosystem
44
Define the term 'Biotic factors' ?
Biotic factor - The living conditions within an ecosystem
45
Explain how abiotic factors are measured ?
- Wind speed : anemometer - Light intensity : light meter - Relative humidity : humidity sensor - pH : pH probe - Temperature : temperature probe - Oxygen content in water : dissolved oxygen probe
46
What are the advantages of measuring abiotic factors using a range of sensors ?
- Rapid changes can be detected - Human error in taking reading is reduced - A high degree of precision can be often achieved - Data can be stored and tracked on a computer
47
What is the equation for Simpson's Index of diversity ?
- This always results in a value between 0 - 1 - 0 means there is no diversity while 1 indicates infinite diversity - The greater the value, the more diverse the habitat/ the greater the biodiversity
48
Do you know how to calculate biodiversity using Simpson's Index of diversity ?
Yes
49
How can biodiversity be measured? How is Simpson's index of diversity better ?
- Can count up the number of species present ( species richness ), however this does not take into account the number of individuals present ( species evenness ) - Simpson's Index of diversity takes into account both species richness and species evenness
50
How can genetic diversity be measured ?
- The proportion of polymorphic gene loci ( number of loci that have two or more alleles ) - The proportion of the population that is heterozygous for any specific gene locus - Allele richness
51
What is a loci ?
The specific linear position of a particular gene on a certain chromosome
52
What is genetic polymorphism ?
When there are two or more alleles present at a single loci
53
What is a polymorphic and monomorphic locus ?
- A monomorphic locus is one that does not have multiple alleles - A polymorphic locus is one that has multiple alleles
54
What is the equation for calculating the proportion of polymorphic gene loci ?
P = number of polymorphic gene loci ÷ total number of loci investigated
55
What are the factors affecting biodiversity ?
- Human population growth - Habitat destruction - Overexploitation - Hunting - Agriculture - Climate change
56
Explain how human population growth is affecting biodiversity ?
- Human population is increasing at exponential rate - Increased need for space for housing, farming and industry ( requiring deforestation )
57
Explain how habitat destruction is affecting biodiversity ?
- Land is cleared resulting in habitat loss and habitat fragmentation ( populations in separated fragments suffer from inbreeding/ local extinction ) - Deforestation - Destruction of marine habitats such as coral reefs and sea beds
58
Explain how overexploitation is affecting biodiversity ?
- Resources are used up at a faster rate than they are being replaced - Deforestation is unsustainable as trees are removed but are not replaced by replanting - Fish are overfished which affects other species dependant on them
59
Explain how hunting is affecting biodiversity ?
- Wild, non-farmed species of animals are being hunted and removed more quickly than their wild populations can be replenished - This affects other species which are dependant not them
60
Explain how agriculture is affecting biodiversity ?
- Monocultures support much lower levels of biodiversity - Fields were made bigger to accommodate machinery via the removal of hedgerows which are an important habitat for many species - Fertilisers can leach into waterways, causing eutrophication - Pesticides (e.g. insecticides) kill many non-target species
61
Explain how climate change is affecting biodiversity ?
- Increases temperatures melt ice caps destroying habitats - Sea levels rise which cause flooding and destruction of terrestrial habitats - Lower rainfall resulting in arid/ extreme conditions causing species to go extinct
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