Biodiversity Flashcards
define biodiversity
the variety of living organisms in an area
what is habitat diversity?
the number of different habitats in an area
what is species diversity?
the number of different species and the abundance of each species in an area
what is genetic diversity?
variation of alleles within a species or population of species
what is random sampling?
divide area into a grid using measuring tape
pick random sample sites using number generator for coordinates
each sample site has same probability of being chosen
what is non- random sampling? (3 types)
systematic sampling:
samples taken at fixed intervals, often along a line
opportunistic sampling:
samples chosen by investigator (very biased)
stratified sampling:
different areas in a habitat are identified and sampled separately in proportion to their part of the habitat as a whole
what are different ways of estimating biodiversity?
pitfall trap- a small pit that insects cant get out of
pooter- safely suck small insects through a tube into a jar
tullgren funnel- a sample of soil or leaf litter put on mesh with light shone on it- heat source- water dries- insects fall into beaker
kick sampling- kick sediment at bottom of stream, hold net to where you kicked and collect organisms
sweep net- stand still and sweep net once from left to right through grass- turn contents onto collecting tray
capture- mark- recapture
what is species richness and species evenness?
richness: number of different species in an area
evenness: measure of relative abundance of each species in an area
what is the importance of genetic diversity?
if a population has low genetic diversity, they may not be able to adapt to a change in the environment and the whole population could be wiped out by a single event e.g. disease
what is polymorphism?
alleles of the same gene are always found at the same point (locus) on a chromosome
polymorphism describes a locus that has two or more alleles
how do you assess genetic diversity?
proportion of polymorphic gene loci= number of polymorphic gene loci/ total number of loci
what are the factors that affect biodiversity? (4 factors)
habitat loss: human population grows so more land needs to be used for housing, destroying habitats
over- exploitation: a greater demand for resources means a lot is used up faster than it can be replenished- destroy habitats
urbanisation: cities and road developments can isolate species, meaning populations are unable to interbreed; genetic diversity decreases
pollution: more waste and more pollution can kill species or destroy habitats
in what ways does monoculture lead to a decline in biodiversity? (3 factors)
habitat loss: land is cleared to make way for large fields, reducing habitat diversity marine fish farms built in locations ideal for wild fish
loss of local plants and animals: local and naturally occurring plants and animals are seen as weeds and pests and are destroyed with pesticides and herbicides- reduces diversity
loss of heritage varieties: they dont make enough money and are not planted anymore
how does climate change affect biodiversity?
droughts- no water - plants cant grow
melting ice caps- reduces habitat biodiversity
rise in sea levels- flooding- reduces habitats
change in temp- storms- reduces habitat
what are ecological reasons to maintain biodiversity?
organisms are interdependent on each other
loss of species disrupts food chains, nutrient cycles
maintaining genetic resources such as crops used for medicine, microorganisms in industrial processes, or animal breeds
genetic resources allow us to adapt to changes in environment
