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OCR Biology A Level > 4.2.1 Biodiversity > Flashcards

4.2.1 Biodiversity Flashcards

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1
Q

Define species

A

Organisms similar in appearance, anatomy, physiology, biochemistry and genetics, whose members are able to interbreed freely to produce fertile offspring

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2
Q

Define habitat

A

The place where an organism lives

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3
Q

Define population

A

A group of organisms of the same specie living in the same area at a particular time

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4
Q

Define community

A

All the populations of different species living in a habitat

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5
Q

Define ecosystem

A

A physical area that includes all living organisms AND non-living components AND their interactions with each other

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6
Q

What is a niche?

A

The roles of a species in an ecosystem e.g. it’s position in a food web

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7
Q

Define biodiversity

A

The variety of life, habitats, number of species and genetic biodiversity within species

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8
Q

What are the three levels of biodiversity?

A
  • habitat biodiversity
  • species biodiversity
  • genetic biodiversity
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9
Q

Give key aspects of habitat biodiversity

A
  • number of different habitats found within the area
  • each habitat supports many different types of species
  • the more species present, the more niches must be available, therefore greater habitat biodiversity
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10
Q

How is species biodiversity composed?

A

Species richness: The no of different species living in a particular area
Species evenness: The relative abundance of each species in an area

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11
Q

How many species are there estimated to be, but why can’t we be sure?

A

~1.3 million
- we can’t be sure all species on earth have been found
- new species are constantly being found
- evolution and speciation are continuing
- endangered species and extinction

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12
Q

How is biodiversity in genetics achieved?

A

All organisms have roughly the same set of genes, however different species have different versions of alleles, giving different characteristics

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13
Q

How does genetic biodiversity increase the chance of a species surviving long term?

A

Greater range of alleles, so greater chance of organism surviving change in the habitat
E.g. some indivduals will be resistant to a new diseases, so less probability the species will be wiped out by the disease

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14
Q

Explain the difference in stability between high and low biodiversity

A

High
- change in environment effects one species
- species is only small proportion of number of organisms
- effect on habitat reasonably small, so habitat can withstand change

Low
- habitat dominated by small number of species
- change in environment effects this species
- thios species is a larger proportion of total number of organisms
- large effect on whole habitat - habitat may not recover from change

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15
Q

Give key aspects of sampling

A
  • not practical to count all species in an area - instead sample small area and multiply to find estimate of whole area
  • take measurement of limited number of individuals present in an area
  • used to estimate number of organisms in area without counting them all
  • abundance = number of individuals of species present
  • gives estimate about number of organisms + distribution of species/measured characteristics
  • can be random or non-random
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16
Q

Why is sampling done randomly?

A
  • to avoid biased results
  • to make sample representatiove of area
  • if sampling not random, over or underestimate of diversity could be created
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17
Q

How is sampling made random?

A

Using a random number generator or random number table

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18
Q

What can affect the number of species sampled?

A

Bigger number sampled = more representative results
- time
- diversity of habitat
- no new species found

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19
Q

What are quadrats and what are they used for?

A

A frame that forms a known area (e.g. 0.5x0.5m) used to work out density, frequency, percentage cover
Used to sample plants and immobile species (can’t be used for mobile species)

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20
Q

How is density calculated using a quadrat?

A

Count number of individual species in a 1x1m quadrat = density/m^2

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21
Q

What is percentage frequency when using a quadrat?

A

The proportion of quadrats that contain a particular species e.g. species found in 30/100 quadrats taken, frequency = 30%

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22
Q

What is percentage cover when using a quadrat?

A

A visual estimate of the area within a quadrat that a particular species covers
- used for speed when a particular species is abundant or difficult to count
- if over half the square is coverd count it, if less than half don’t

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23
Q

What is a point quadrant?

A

An apparatus consisting of a free standing frame with a row of ten sliding pins, lowered down onto vegetation - record kept of number and each species of plant touching each pin

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24
Q

What is the ACFOR scale?

A

Scale measuring species abundance:
A = Abundant (greater/equal to 30%)
C = Common (20-29%)
F = Frequent (10-19%)
O = Occasional (5-9%)
R = Rare (1-4%)

Quick but subjective

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25
Q

Explain the steps of the process of random sampling

A
  1. Lay out two tape measures at right angles along sides of study area
  2. Obtain 2 coordinates using RNG
  3. Place top left quadrat at coordinate
  4. Use key to identify species
  5. Estimate percentate cover/use ACFOR scale
  6. Calculate mean
  7. Sample at different times of year
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26
Q

Name and explain the three types of non-random sampling

A

Opportunistic
Uses organisms conveniently available - weakest form of sampling as may not be representative of population
Stratified
Populations divided into sub groups called strata, based upon particular characteristic (e.g. sex, age groups)
Random sample taken from each strata, proportional to size, reducing bias in results
Systematic
Used to study changes accross an area, often using a line or belt transect
Line transect: Line made along ground + taking samples at specifed points
Belt tramsect: Two parallel lines marked and samples taken between the two lines

27
Q

Explain the steps of the process of systematic sampling using a line transect

A
  1. Place tape measure in line along study site
  2. Record species touching line at regular intervals e.g. every 5m
  3. Use key to identify species
  4. Repeat sampling over time + repeat in one area
    Used to show how communities change/are distributed along a gradient
28
Q

Explain the steps of the process of systematic sampling using a continous belt transect and explain how an interrupted belt transect differs

A
  1. Place 2 tape measures in line along study site
  2. Place quadrat between tape measures and esitmate percentage cover/ ACFOR scale at every part of line
  3. Use key to identify species
  4. Repeat samplimng over time + repeat in one area

Interrupted places quadrats at regular intervals like in a line transect

29
Q

Explain three ways mobile species can be sampled

A

Pitfall trap: Used to catach small crawling vertebrates. Make sure is deep enough so they don’t crawl out + roof structure popped up so trap doesn’t fill with water
Sweep netting: Used to catch insects in area of long grass
Pooters: Person sucks a mouthpiece, drwaing insects into chamber via inlet tube (filter before mouthpiece prevents sucking into mouth) - used to catch small insects

30
Q

How can sampling methods be improved?

A
  • random selection of sample area with random co-ordinates
  • sample area many times to calculate mean
  • used standardised sampling technique e.g. net sweeping from same height/ same no. sweeps/ same size pitfall trap
  • use mark-release-recapture so individuals not counted twice
  • sample area at different times of day/year
31
Q

Explain the process of mark-release-recapture

A
  1. Capture sample of individuals from species poopulation
  2. Mark captured individuals
  3. Release back into habitat and wait for time period
  4. Capture second sample
  5. Use lincoln index to calculate population size (No. 1st sample X No. second sample) / No. marked in 2nd sample)
32
Q

What must be ensured when using mark-release-recapture

A
  • minimal damage to sampling area
  • species moved should be reutnred to same area
  • sites should not be over used
  • minimal distress to organisms
  • envionmental impact assessment (EIA) done
  • mark must be non toxic + not increase predation
33
Q

What are problems with mark-release-recapture?

A

Assumes that:
- samples are representative of whole population
- marked organisms mix evenly with rest of population
- there has been no immigration/emigration from population
- there has been no births/deaths

34
Q

What is simpsons index of biodiversity and what data is require d to work it out?

A

A formula to measure biodiversity. The closer the value to 1, the more diverse + stable the habitat.
Requires No. species in area + No. individuals of each species in area

35
Q

How are humans reducing biodiversity?

A

Deforestation - removal of forest for timber for building + fuel + create space for roads/building/agriculture
Agriculture - large amounts cleared for single crop grown (monoculture)
Climate change - release of greenhouse gases increasing global temperature

36
Q

How does deforestation reduce biodiversity?

A
  • directly reduces the number of trees present in an area
  • specific types of tree are felled, reducing species diversity
  • reduces no. animal species present - destroys habitats + food sources + forces migration to other areas
37
Q

How does agriculture reduce biodiversity?

A
  • removal of hedgegrows to free up land/allow use of large machinery - reduces no plant species in area + destroys animal habitatsa
  • pestricides used reduces species diversity by killing insects + indirectly killing food source of other organisms
  • herbicides reduce species divesiryt by killing weeds - indirectly killing food source of other organisms
  • monoculture - lowers local biodiversity as only one species of plant is present, supprting few animals
  • may cause humans harm due to bioaccumulation in food chains/webs
38
Q

What advantages do hedgerows provide?

A
  • food + shelter for species
  • control water levels + runoff
  • pest control as habitats for predators
  • crop pollination by insects
39
Q

What is the greenhouse effect?

A
  1. Fossil fuels burning + deforestatiuon releases CO2
  2. Cattle + rice fields produce methane
  3. Allow less sunrays to leave the atmosphere, leading to global warming
40
Q

How does climate change reduce biodiversity?

A
  • melting polar ice caps leads to extinction of species living in these areas
  • rising sea levels from melting ice caps floods low lands areas, destroying habitats
  • risisng sea levels causes seawater to flow up rivers, reducing habitats of freshwater plants + animals
  • high temps + low rainfall cause plants to fail to survive + lead drought resistant species to become more dominant, leading to loss of animal species
  • insect life cycles + populations change - affect pollination and therefore lives of plants, causing extinction
41
Q

Give examples of the consequences climate change has on biodiversity

A
  • diseases of domestic animals increase e.g. blue tongue in cattle
  • pests of plants + fungal infections nirmally killed by frost may survive over winter
  • vectors of diseases (e.g. female mosqauitos carrying malraia) can survive in morea areas
  • mangroive swamps depends on roots being ourt of water - rising sea levels will lead to destruction of these hjabitats
  • some fish species stop growign at a certain temperature - rising temperatures could cause growing to stop before reproductive age or before they’re at a sufficeint weight to survive the winter
42
Q

What are the aesthetic reasons for maintaining biodiveristy?

A
  • enrichment of lives - relaxing walks on beach/through woodland
  • provides inspiration for people e.g. musicians + writers
  • can make patients recover quicker from stress/injury when supported by plants/ natural environment
43
Q

What are the economic reasons for maintaining biodiveristy?

A
  • soil erosion + desertification from defroestation reduces a countries ability to grow crops - so rely on other countries
  • non-sustainable removal of resources e.g. timber will lead to indsutry collapse
  • species with potential economic importance (e.g. medical or chemical value) may become exitinct before they’re discovered
  • ecotourism - areas that are attrative provide tourism - providing jobs + money to the local community
  • monoculture leads to drops being more vulnerable to pests + disease - farmers have to spend more money on pesticides/herbicides/fertilisers
  • high biodiversirty provides protection from abiotic stresses (climate change/natural disasters/disease) - when not maintained a change in condition can completley destroy a crop
  • greater diversity = greater potential for manufacture of different products (more money + jobs)
  • plant varieties needed for cross breeding, which can yield better characteristics e.g. disease resistance + increased yield
44
Q

What are the ecological reasons for maintaining biodiveristy?

A
  • organisms are part of a good chain - interdependant on others for survival (e.g. bees for pollination)
  • keystone species - species that play a key role in maintaining the structure of an ecological community - have a disproprtionally large effect on environment + when removed the habitat is drastically changed
  • genetic variation leads to evopultion by natural selcetion - without this organisms can’t adapt to environmental change
45
Q

What other reasons for maintaining biodiveristy?

A
  • organisms have a right to exist
  • religous reasons
46
Q

What is in-situ conservation and give examples?

A

Conservation of a species in its natural habitat
- marine conservation zones (e.g. great barrier reef)
- wildlife reserves (e.g. grand canyon)

47
Q

What are the advantages and disadvantages of in-situ conservation?

A

Advantages
- habitat + organims within habitat conserved
- biodiversity of whole area maintained
- cheaper as just requires managing
- allows continuation of evolution
Disadvantages
- large amounts of land needed + may cross borders possibly causing conflict
- difficlt to manage large areas
- locals may still hunt animals/ harvest plants/timber from area
- animals may leave reserve, causing locals probelsm
- harder to control disease, fires, flooding
- nowhere for species to move if climate change occurs

48
Q

What do in-situ conservation charities do?

A
  • purchase land
  • setup + manage nature reserves
  • recruit + train volunteers
  • educate + public awareness
  • national campaigns
  • give lectrues + publish magazines
  • wildlife surveys
  • lobby the government
49
Q

Give key aspects of wildlife reserves

A
  • controlled grazing
  • limited human access (completley or via footpaths)
  • controlled poaching
  • feeding animals
  • reintrouction of species
  • culling/removal of invasive species
50
Q

Give key aspects of marine conservation zones

A
  • preserve species rich areas - coral reefs
  • create refuge areas for populatiosnto build up - helps repopulatiuon of areas next to these areas
    -don’t prevet fishermen from visiting entire area - coral reefs devastated by non-sustainable fishing methods
51
Q

What in-situ reserves are present in the UK?

A
  • 14 national parks
  • 224 national nature reserves
  • 6000 sites of special scientific interest
  • 1500 local nature reserves
52
Q

What is ex-situ conservation and give examples?

A

Conservation of a species by removal of the organism from its natural habitat
- botanical gardens for plants
- seed banks for plants
- captive breeding programmes for animals

53
Q

Give key aspects of botanic gardens and seed banks

A

Botanic gardens
- plant species actively managed
- provided with best resources to grow (soil mineral ions, watering, pest removal)
- wild relatives of selectively bred species still under represented - potential source of genes, resistance to disease,pests,parasites

Seed banks
- gene bank - stores geneteic material
- stores temperate + tropical seeds
- seeds remain viable for centuries
- back up against extinction of wild plants

54
Q

Give the main aims, advantages and disadvantages of seed banks

A

Aims
- seeds stored + germinated regularly (to renew stock + maintain viability)
- plant number increased quickly then reintroduced into wild
Advantages
- seeds produced in excess + stored in large amounts
- seeds collected without disturbing habitats of wild plants
- seeds take up little space
- easy + cheap to transport
- remain viable for long time + less susceptible to disease
Disadvantages
- at risk from power failure, natural disaster, war
- seeds do not evolve with changes in environment
- collection of wild seed will cause some disturbance
- samples not representative of total genetic diversity
- asexual breeding means clones
- seeds stored for long time may not grow

55
Q

Why is it important for seed banks to collect samples of the same species from different sites around the world?

A
  • increased genetic variation
  • reduces chance that a disease or environmental change will affect the whole population
  • reduces chances of interbreeding
  • maintains geographical variation
56
Q

Give key aspects of captive breeding programmes (ex-situ)

A
  • run and managed by zoos + aquatic centres
  • aim to produce a stable, healthy population species + gradually reintroudce back into the wild
  • provide animals with shelter, food supply, absence of predators, vets
  • breeding arranged by international catalogue to prevent inbreeding
  • last resort for species populations that wouldn’t recover in the wild
  • works well for species easily bred in captitvity but not sure more specialised animals
  • isolated so don ‘t evolve with environment
57
Q

What individuals are selected for captive breeding programmes?

A
  • not related
  • healthy
  • of reproductive age
  • opposite sex + higher proportion of females
  • different areas to increase genetic variation
  • housaed in different centres to reduce risk of inbreeding + less chance of losing individuals through disease/natural disaster
58
Q

Give key aspects of repopulation (takes place after captive breeding)

A
  • healthy + quarantined before release
  • must have adequate natural hfood supply or introduce feeding programme
  • protected reserve
  • population moniotrinhg
  • prepare animal for release (e.g. teaching how to hunt)
  • removal of major threats to survival (no hunting + educate farmers)
  • promotion of ecotourism)
  • sperm + egg bank/forzen embryos incase of population decline
59
Q

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

A
  • loss of resistance to local diseases
  • behaviour learned through copying or expericing not learned (e.g. don’t know they have to search for food)
  • genetic make-up different original population so can’t interbreed
  • can lead to stress on habitat, particularly if all - individuals may fight for territory + resources
60
Q

What is the International Union for the Conservation of Nature (IUCN)?

A
  • intergoverenmental organisation
  • assists in securing agreements between nations
  • publishes the ‘red list’ which details conservation status of threatened animals
  • countries work together to conserve species as animals cross borders
  • involved in the establishment of the Convention of International Trade in Endangerd Species (CITES)
61
Q

What is the Convention of International Trade in Endangerd Species (CITES)?

A
  • protects 35000 species
  • aims to protect/conserve endangered species by preventing trade of endangered species
  • restricts cross border-wildlife trade
  • prohibits commerical trade in wild plants
  • allow trade in artificallty propagated plants
  • allows trade in less endangered species subject to permit
62
Q

Give key aspects of The Rio Convention

A
  • 1992 meeting of 172 nations held in Rio to agree conventions to maintain biodiversity
  • The convention of Biological Diversitry (CBD) requires countriues toi develop stratergies for sustainbale develkopment (maintaing biodiversity)
  • The United Nations Framework Convention on Climate Change (UNFCCC) - agreement between nations to take steps to stabalise greenhouse gas concentrations within the atmosphere
  • The United Nations Convention to Combat Desertification (UNCDD) - aims to prevent the transormation of fertile land into desert + reduce effects of drought through international cooperation
63
Q

Give key aspects on the Convention on Biological Diversity

A
  • set up by 150 government leaders in earth summit
  • sustainable conservation of biological diversity
  • shared access to genetic resources (DNA, sperm, eggs, embryos)
  • shared knowledge + technology
  • sharing of benefits of genetic resources
  • counties must use both ex-situ + in-situ
64
Q

What is the countryside stewarship scheme (Now the environmental stewardship scheme)?

A
  • operated from 1991-2014
  • farmers/land managers given governmental payments to enhance + conserve the english landscape
    Aims
  • make conservation part of normal farming + land management practices
  • to sustain the beauty + diversity of the landsacpe
  • improve, extend, create wildlife habitats
  • restore neglected land
  • improve opportunities for countryside enjoyment

OCR Biology A Level (21 decks)

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