Chapter 11 biodiversity flashcards
biodiversity
the variety of living organisms present in an area
areas with most biodiversity
tropical, moist regions
generally closer to equator, greater biodiversity
EIA
environmental impact assessment
- undertaken when a major project occurs, e.g. building new road
3 levels of biodiversity
- habitat
- species
- genetic
habitat biodiversity
refers to the number of different habitats found within an area
the greater the habitat biodiversity, the greater the species biodiversity
species richness
the number of different species living in a particular area
species evenness
a comparison of the numbers of individuals of each species living in a community
community
all the populations of living organisms in a particular habitat
genetic biodiversity
refers to the variety of genes that make up a species
alleles lead to genetic biodiversity within a species
greater genetic biodiversity allows better adaptation to changing environment and more likely to result in individuals who are resistant to disease
sampling
taking measurements of a limited number of individual organisms present in a particular area
can be used to estimate number of organisms in an area
abundance
the number of individuals of a species present in an area
random sampling
selecting individuals by chance
random number tables or computers can be used
3 techniques of non-random sampling
- opportunistic
- stratified
- systematic
opportunistic sampling
uses organisms that are conveniently available
weakest form of sampling
systematic sampling
different areas within an overall habitat are identified and then samples separately
often carried out using a line or belt transect
line transect involves making line along the ground between 2 poles and taking samples at specified points
belt transects involves 2 paralles lines marked and samples taken of area between 2 lines
stratified sampling
some populations can be divided into a number of strata (sub-groups) based on a particular characteristic
a random sample is then taken from each of these strata proportional to its size
sampling bias
selection process may be biased, e.g. may choose to sample a particular area that has more flowers
can be reduced using random sampling
chance (reliability)
organisms selected may not be representative of the whole population
effect can be minimised by using large sample size
