4.2 BIODIVERSITY Flashcards
Define biodiversity
- a measure of variation
State and describe the three types of biodiversity
1) Habitat biodiversity (e.g sand dunes, meadows, streams, woodland)
2) Species biodiversity (species richness and species evenness)
3) Genetic biodiversity (e.g different breeds within a species)
State how biodiversity can be measured
- Sampling
State the two types of sampling
1) Random sampling
2) Non-random sampling
Describe the process of random sampling
- Sample sites inside the habitat are randomly selected
- Can be done by random number generator to determine co-ordinates
- Calculate mean population per sample
- Multiply value to the size of habitat
State two advantages of random sampling
1) Ensures the data is not bias
2) Useful if species are evenly distributed
State two disadvantages of random sampling
1) May not cover equal areas of the habitat
2) Species with a low presence may be missed leading to underestimate of biodiversity
State the three types of non-random sampling
1) Opportunistic
2) Stratified
3) Systematic
Describe the process of stratified non-random sampling
- Dividing a habitat into areas which appear different and sampling each area separately
Describe the process of systematic non-random sampling
- Samples are taken at fixed intervals across the habitat
- Using a line/belt transect
Describe the process of opportunistic non-random sampling
- Deliberately sampling areas that contain a specific species
State an advantage of opportunistic non-random sampling
- Easier/quicker than random sampling
State two disadvantages of opportunistic non-random sampling
- Bias data
- Leads to an overestimate of biodiversity
State an advantage of stratified non-random sampling
- Ensures species are not underrepresented as all different areas of habitat are sampled
State a disadvantage of stratified non-random sampling
- May lead to over-representation if disproportionate number of samples taken in small areas that look different
State an advantage of sytematic non-random sampling
- Shows a clear gradient in the habitat biodiversity based on an environmental factor
State a disadvantage of systematic non-random sampling
- Only species on the line/belt can be sampled so may lead to underestimate of biodiversity
Define sampling
- Measuring small portions of a larger population to make assumptions of the whole population
State the four instruments used to sample animals
1) Sweep nets
2) Pooter
3) Pitfall trap
4) Tullgren funnel
State the two instruments used to sample plants
1) Quadrat
2) Transect line/belt
Define allele/gene variant
- A version of a gene
Define locus
- The position of a gene on a chromosome