11 - Biodiversity Flashcards
What are the different levels of biodiveristy?
habitat biodiversity
species biodiversity
genetic biodiversity
What is habitat diversity?
the number of different habitats in an area
- e.g one area could contains lots of habitats
- sand dunes
- woodlands
- meadows
- streams
What is species diversity?
the number of different species (species richness) and abundance of each species (species evenness) in an area.
what is species richness?
the number of different species in an area.
what is species evennness?
the relative abundance of each species in an area.
what is genetic diversity?
the variation of alleles within a species (or a population of species).
How can sampling be used to measure biodiveristy?
- choose an area to sample (small area within a habitat).
- count the number of individuals of each species.
- repeat the process many times to get have a better representative of the whole habitat.
- use the results to estimate the total number of species and individuals in the habitat.
What tools do you use to sample different organisms for when measuring biodiversity?
plants: quadrat flying insects: sweep net ground insects: pitfall trap insects: pooter aquatic animals: net
Why are samples taken to measure biodiversity in a habitat?
- too time consuming to count every individual in a habitat.
- samples provide an estimate about the whole habitat.
what is random sampling?
- random sampling means selecting individuals by chance.
- each individual has an equal chance of selection.
- avoids bias
- measuring tapes to divide area into a grid.
- random number generator to generate random coordinates.
what is non-random sampling?
sample is not chosen at random.
systematic sampling
opportunity sampling
stratified sampling
what is systematic sampling?
- samples are taken at fixed intervals.
what is opportunistic sampling?
- samples are chosen by the investigator.
- bias
- simple to carry out
what is stratified sampling?
when different areas within a habitat are identified and sampled separately in proportion to their part of the habitat as a whole.
- different sub groups are called strata based on a particular characteristic.
reliability of sampling
never 100% reliable or representative
there may be bias or by chance the may not be representative.