Module 4: Biodiversity Flashcards
Define biodiversity.
Variety of living organisms in an area.
Define species.
A group of similar organisms able to reproduce to give fertile offspring.
Define habitat.
The area inhabited by a species, including abiotic and biotic factors.
What is habitat diversity?
The number of different habitats in an area.
What is species diversity?
The number of different species in an area.
What is genetic diversity?
The variation of alleles within a species/population.
What is a pitfall trap?
A small pit that insects can’t get out of.
What organism would a pitfall trap be used for?
Crawling ground insects.
What is a pooter?
A device that allows you to safely suck small insects through a tube in a jar.
What organism would a pooter be used for?
Crawling ground insects.
How does a Tullgren funnel work?
*a soil or leaf litter sample is put on a mesh filter at the top of a funnel
*light is shone down onto it
*organisms move away from the heat and fall out of the funnel into a collecting beaker
What organisms would a Tullgren funnel be used for?
Small ones that live in soil or leaf litter.
What is kick sampling?
Gently kicking the bottom of a stream and using a net to collect the disturbed organisms.
What is sweep sampling?
Sweeping a sweep net through long grass.
What is a sweep net?
A net lined with strong cloth on a pole.
What is one way a random sample can be taken?
*divide the field into a grid using tape measures
*use a random number generator to select coordinates
What are the three types of non-random samples?
*systematic
*opportunistic
*stratified
What is systematic sampling?
When samples are taken at fixed intervals.
Give an example of systematic sampling.
To count plant species in a field, place quadrats along a line (transect).
What is opportunistic sampling?
When samples are chosen by the investigator.
What is a problem with opportunistic sampling?
The data will be biased.
What is statified sampling?
When different areas in a habitat are identified and sampled separately in proportion to their part of their habitat as a whole.
What is species richness?
The number of different species in an area.
What is species evenness?
A measure of the relative abundance of each species in an area.
What is Simpson’s Index of Diversity used for?
Measuring diversity, taking into account species richness and eveness.
What is the formula for Simpson’s Index of Diversity?
D = 1-(Σ(n/N)^2)
What does the n mean in Simpson’s Index of Diversity?
Total number of individuals of one species.
What does the N mean in Simpson’s Index of Diversity?
Total number of organisms of all species.
What is Simpson’s Index of Diversity value always between?
0 and 1
What does it mean if Simpson’s Index of Diversity is closer to 1?
The more diverse the habitat is (greater species richness and evenness).
What does it mean if a population has low genetic diversity?
They might not be able to adapt to a change in the environment and the whole population could be wiped out by a single event.
Give examples of populations that might have low genetic diversity.
Isolated populations - those bred in captivity:
*zoos
*pedigree animals
*rare breeds
What is a locus on a chromosome?
The point where the alleles are found.
What is polymorphism?
A locus that has two or more alleles.
What does working out proportion of polymorphic gene loci in an organism give you?
A measure of genetic diversity.
What is the formula for proportion of polymorphic gene loci?
Proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci
What are the three main factors affecting biodiversity?
*human population growth
*increased use of monoculture
*climate change
What are the four ways human population growth has decreased global biodiversity?
*habitat loss
*over-exploitation
*urbanisation
*pollution
How has habitat loss decreased biodiversity?
Destroying habitats (e.g. deforestation).
What type of diversity does habitat loss decrease?
Habitat diversity.
How has human population growth increased over-exploitation?
*greater demand for resources
*resources being used up faster than they can be replenished
What types of diversity does over-exploitation decrease?
*genetic diversity
*species diversity
How does urbanisation decrease biodiversity?
*sprawling cities and major road developments can isolate species
*populations are unable to interbreed
What type of diversity does urbanisation decrease?
Genetic diversity.
How does pollution decrease biodiversity?
High amounts of pollutants can kill species or destroy habitats.
What is monoculture?
The growing of a single variety of a crop.
How does monoculture decrease habitat biodiversity?
Habitats are lost as land is cleared for large fields.
How does monoculture decrease species biodiversity?
*local and naturally occurring plants and animals are seen as weeds and pests, so are destroyed with pesticides and herbicides
*heritage (traditional) varieties of crops are lost because they don’t make as much money and aren’t planted
How does climate change causes increases and decreases in biodiversity?
*most species need a particular climate to survive
*a change in climate may mean a previously inhabitable area becomes uninhabitable
*increase or decreases range of some species
How does climate change effect species biodiversity?
*some species forced to migrate to a more suitable area
*changes species distribution
*increases biodiversity in areas they migrate to
*decreases biodiversity in areas they migrate from
How does climate change decrease biodiversity?
*if there isn’t a suitable habitat to migrate to, the specie is a plant or the change is too fast
*species may become extinct
