Biodiversity Revision Notes
Biodiversity
- it is the variety of life and the range of living organisms that can be found in a range of habitats
Habitat Biodiversity
-range of organisms habitats in which different species live in
e.g. damp, dry, hot, cold, sun, shade, ponds
Species Biodiversity
-physical/anatomical differences between species
-species can interbreed to produce fertile offspring
-can be measures in 2 ways
Species Evenness – is the relative abundance of individuals in each species
Species Richness – is the number of species in a habitat
Genetic Biodiversity
-genetic variation between individuals within a species
-creates breeds within a species (breeds of cats and dogs)
Sampling
Random Sampling
-sample sites are randomly selected
-can use randomly generated numbers as coordinates for the sample
-selecting coordinates from a map and using GPS for exact position
Advantages Disadvantages
-ensure data is not biased -may not cover all areas of the habitat equally
-may lead to a misrepresentation of species
Non-Random Sampling
Opportunistic
-makes sampling decisions based on prior knowledge of the area
Advantages Disadvantages
-easier and quicker than random sampling -data might be biased
-may lead to a misrepresentation of a species
Stratified
-dividing a habitat into two spate area (look different) and sample each one individually
Advantages Disadvantages
-all the different areas are sampled -over-representation of species in some areas
-minimises chances of misrepresentation of species
Systematic
-samples are taken from fixed intervals across a habitat (transects)
Advantages Disadvantages
-useful when habitat shows clear gradient -only species on the transect line are recorded
-species may be missed
Reliability of Sampling
-sample is never entirely representative of the organisms in a habitat
-this may be because:
Bias – selection process may be biased ether by accident or purpose (chose an area with more flowers as it looks interesting)
Chance – organisms selected are not representative of the whole population (5 works collected in a trap are the longest in the habitat)
Biodiversity
- it is the variety of life and the range of living organisms that can be found in a range of habitats
Habitat Biodiversity
-range of organisms habitats in which different species live in
e.g. damp, dry, hot, cold, sun, shade, ponds
Species Biodiversity
-physical/anatomical differences between species
-species can interbreed to produce fertile offspring
-can be measures in 2 ways
Species Evenness – is the relative abundance of individuals in each species
Species Richness – is the number of species in a habitat
Genetic Biodiversity
-genetic variation between individuals within a species
-creates breeds within a species (breeds of cats and dogs)
Sampling
Random Sampling
-sample sites are randomly selected
-can use randomly generated numbers as coordinates for the sample
-selecting coordinates from a map and using GPS for exact position
Advantages Disadvantages
-ensure data is not biased -may not cover all areas of the habitat equally
-may lead to a misrepresentation of species
Non-Random Sampling
Opportunistic
-makes sampling decisions based on prior knowledge of the area
Advantages Disadvantages
-easier and quicker than random sampling -data might be biased
-may lead to a misrepresentation of a species
Stratified
-dividing a habitat into two spate area (look different) and sample each one individually
Advantages Disadvantages
-all the different areas are sampled -over-representation of species in some areas
-minimises chances of misrepresentation of species
Systematic
-samples are taken from fixed intervals across a habitat (transects)
Advantages Disadvantages
-useful when habitat shows clear gradient -only species on the transect line are recorded
-species may be missed
Reliability of Sampling
-sample is never entirely representative of the organisms in a habitat
-this may be because:
Bias – selection process may be biased ether by accident or purpose (chose an area with more flowers as it looks interesting)
Chance – organisms selected are not representative of the whole population (5 works collected in a trap are the longest in the habitat)
