Topic 4: Biodiversity Flashcards
Biodiversity definition
Biodiversity = the variety of living organisms in an area
Habitat Biodiversity
Habitat biodiversity = number of different habitats in an area
Species biodiversity
Species biodiversity = the number of different species and their abundance in an area
Genetic biodiversity
Genetic biodiversity the number of different alleles within a species or population
Importance of biodiversity
Biodiversity is important in maintaining the balanced ecosystem for all organisms as all species are interconnected (they rely on eachother)
Levels of which biodiversity can be studied
Levels of which biodiversity can be studied:
-Habitat biodiversity
-Species biodiversity
-Genetic biodiversity
Why is it important to measure biodiversity?
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
Two components of species biodiversity
Two components of species biodiversity:
-Species richness = the number of different species in a habitat
-Species evenness = the number of individuals within each species
Community definition
Community = all the populations of living organisms in a particular habitat
Result of a greater genetic biodiversity
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
Issues that come with measuring biodiversity
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
How do you ensure the sample of an area if valid and representative?
Random sampling technique ensures samples are valid and representative.
What is species richness?
Species richness is the number of different species in a habitat
How to calculate species evenness
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
Types of sampling
Types of sampling include:
Random sampling
Non-random sampling
Stratified
Systematic
Random sampling
Random sampling refers to selecting individuals by chance eg random number tables or computers.
Non-random sampling
Non-random sampling is where it’s not chosen at random, and can be divides into three techniques:
-Opportunistic
-Stratified
-Systematic
Opportunistic sampling
Opportunistic sampling - weakest sampling - may be unrepresentative - uses organisms that are conveniently available
Stratified sampling
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
Systematic sampling
Systematic sampling - different areas within a habitat identified and sampled seperately - often carried out with transects - line or belt transect
Reliability of sampling
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
Techniques used for sampling animals
Techniques used for sampling animals:
-Pooter
-Sweep nets
-Pitfall traps
-Tree beating
-Kick sampling
Pooters
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
Sweep nets
Sweep nets are used to catch insects in areas of long grass
Pitfall traps
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
Tree beating
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
Kick sampling
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
Why is it difficult to estimate population size of organisms?
Estimating population size is difficult due to organisms constantly moving or hiding
How to estimate population size?
Population size can be estimated using the capture-recapture method
Capture-mark-release-recapture method for estimating population size
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
Types of quadrats
Types of quadrats:
Point quadrat
Frame quadrat
Point quadrats
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
Frame quadrats
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
How to measure species richness?
Measuring species richness:
-Compile list of each species identified
-Total number of species calculated
-Identification keys used to accurately identify species
How to measure species evenness?
Measuring species evenness:
-How close in numbers the population of each species in an environment are
Calculating population density of species evenness
Density:
-Use a frame quadrat
-Count number of individual large plants
-Absolute measure (not estimate)
Measuring frequency of species evenness
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
Calculating percentage cover of species evenness
Percentage cover:
-Used for speed
-An estimate by eye of the area within a quadrat that a particular plant species covers
Advantages of the different ways of measuring species evenness
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
Disadvantages of the different ways of measuring species evenness
Disadvantages of the different ways of measuring species evenness:
-Population density: Time consuming
-Frequency: only approximate result
-Percentage cover: only approximate result
Advantages of using a temperature probe rather than a thermometer
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
Importance of sampling in measuring the biodiversity of a habitat
Importance of sampling in measuring the biodiversity of a habitat:
-Sampling is quicker, and more representative
Difference between species richness and evenness and why are they both needed to assess biodiversity?
-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
Significance of a low value of simpson’s index of diversity
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
Sampling strategy that should be used when finding biodiversity of different areas within an ecosystem
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)
How to measure the frequency of organisms within a sample
Frequency:
-Count organisms
-Divide that by the area surveyed
Simpson’s index of diversity
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
Why is biodiversity important?
Biodiversity is important due to interdependance of species
What do the value indicate in the Simpsons Index of Diversity?
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
What habitat features are associated with low biodiversity?
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
What features are associated with habitats that have a high biodiversity?
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
Uses of sampling
Uses of sampling:
can estimate abundance (without having to count them all) and can measure a particular characteristic (mean height of plants for example)
Belt transects
Belt transects: Two parallel lines are marked along the ground and samples are taken of the area at specified points
High genetic biodiversity
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
Reasons why sampling is carried out
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
Advantages of random sampling
Advantages of random sampling: no bias, more representative, all organisms have an equal chance to be selected
Advantages of non-random sampling
Advantages of non-random sampling:
-Allows for easier comparison between abiotic factors
-Easier to conduct and cheaper, and faster
How to sample an area of grassland
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
Reasons for conservation of plant species eg trees
Reasons for conservation of plant species eg trees:
-Aesthetic value
-Potential source of medicine
-Maintaining habitats for species
Situ and ex-situ meaning
Situ: In it’s natural/original place
Ex-situ: Not in it’s natural/original place
Advantages of using seed banks rather than just using adult seeds as a means to conserve an endangered species
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
Why are seeds in a seedbank taken from different areas?
Seeds in a seedbank is taken from different areas because:
-To maintain genetic biodiversity
-Reduced chance of further disease
-Maintain geographical variation
Meaning of a low simpsons index
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
How to ensure an accurate simpsons index value:
How to ensure an accurate simpsons index value:
-Use of random sampling
-Sample at different times of the year
Benefit of index of diversity
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.
Genetic biodiversity calculation
Genetic diversity =
total number of loci/
number of polymorphic gene loci
x 100
Importance of genetic biodiversity
Importance of genetic biodiversity:
-Essential to the survival of a species
-Helps monitor the health of the population and ensure its long-term survival
Genetic biodiversity
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
Benefits of genetic biodiversity
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
Factors that affect genetic biodiversity
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
Selective breeding affect on genetic biodiversity
Selective breeding:
-Few individuals are selected for their advantageous characteristics
-Allele frequency decreases as advantageous allele increases
Captive breeding affect on genetic biodiversity
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
Rare breeds affect on genetic biodiversity
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
Artificial cloning affect on genetic biodiversity
Artificial cloning:
-Using cuttings to clone a farmed plant
-Only alleles from the clone are passed to offspring
-Reduces allele frequency
Natural selection affect on genetic biodiversity
Natural selection:
-Species evolve to contain the alleles for advantageous characteristics
-Alleles coding for less advantageous characteristics will be lost from the population
Genetic bottlenecks affect on genetic biodiversity
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
Founder effect on genetic biodiversity
Founder effect:
-Small number of individuals create a new colony, geographically isolated from the original
-Gene pool for the new population is small
Genetic drift affect on genetic biodiversity
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
How to measure genetic biodiversity
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
Monomorphic genes
Monomorphic genes - genes with one single allele - this ensures that the basic structure of individuals within a species remain consistent
Measuring genetic biodiversity equation (proportion of polymorphic gene loci)
-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
Factors affecting biodiversity
Factors affecting biodiversity:
-Deforestation
-Agriculture
-Climate change
Human influence on biodiversity
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
Deforestation affect on biodiversity
-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)
Agriculture affect on biodiversity
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
Climate change affect on biodiversity
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
Reasons for maintaining biodiversity
Reasons for maintaining biodiversity:
-Aesthetic
-Economic
-Ecological
Aesthetic as a reason for maintaining biodiversity
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
Economy as a reason for maintaining biodiversity
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
Ecology as a reason for maintaining biodiversity
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
Economic benefit of a high biodiversity
Economic benefit of a high biodiversity:
-High plant biodiversity supports drug discovery and development
-Tourism industry brings economic benefits
Importance of sampling in measuring the biodiversity of a habitat
Importance of sampling in measuring the biodiversity of a habitat:
-Quick method of measuring population size
-Provides an estimate
-Impossible to count every individual
