4.2 Biodiversity Flashcards
Biodiversity meaning:
Variety of living organisms in an area
Species meaning:
Group of similar organisms which can reproduce and make fertile offspring
Habitat meaning:
Area inhabited by a species, including physical factors (biotic and abiotic)
High biodiversity meaning:
Lots of different species
Habitat diversity meaning:
No. of different habitats in an area. Eg. sand dunes, woodland, meadow
Species diversity meaning:
No. of different species and abundance of each species in an area
Species richness meaning:
No. of different species in an area
Species evenness meaning:
Abundance of each species in an area
Genetic diversity meaning:
Variation of alleles within a species (eg. dog breeds)
Method to sample plants:
Quadrat
Method to sample flying insects:
Sweep net (net on pole)
Method to sample ground insects:
Pitfall trap
Method to sample aquatic animals:
Net
How to sample (steps):
- Choose area.
- Count individuals (w/ quadrat, net, etc).
- Repeat.
- Use results to estimate total.
Comparing different habitats samples:
Use the same sampling technique
How do you get a random sample?
Split field into a grid, use measuring tape and a random number generator to select coordinates.
When would you take a non-random sample?
When there’s a lot of variety in distribution of species in the habitat, want to make sure all areas are sampled.
Systematic sampling description:
Samples taken at fixed intervals, often along line.
Opportunistic sampling description:
Samples chosen by investigator. Simple but biased.
Stratified sampling description:
Different areas identified + sampled separately in proportion to habitat as a whole.
Non-random sampling techniques:
Systematic, opportunistic, stratified
Greater species richness meaning:
Higher number of species
Greater species evenness meaning:
Population sizes of each species are similar
Simpsons index of diversity equation:
D = 1 - (sum(n/N)^2)
n = total number of individuals in one species
N = total number of organisms in all species
Simpsons index of diversity meaning:
Closer to 1 = more diverse habitat, higher species richness and evenness
Simpsons index of diversity range:
0
Low genetic diversity problems:
Can’t adapt to change in environment, whole population can die from a single disease