Module 4 : Section 2 - Studying Biodiversity Flashcards
Define biodiversity
The variety of organisms in an area
Define species
A group of similar organisms able to reproduce to give fertile offspring
Define habitat
the area inhabited by a species
Areas with high biodiversity are those with….
Lots of different species
How can biodiversity be considered
- habitat diversity
- species diversity
- genetic diversity
What is habitat diversity
the number of different habitats in an area
What is species diversity
The number of different species and the abundance of each species in an area
What is genetic diversity
The variation of alleles within a species
What is sampling used for
To measure biodiversity
What steps does sampling involve
- choose an area to sample
- count number of each species
- repeat process
- uses results to estimate total number of individuals or species in the habitat
- when sampling different habitats and comparing them always use the same sampling technique
Sampling can be…..
- Random
- Non-random
Why should you randomly sample
To avoid bias
How can you randomly sample
If sampling plants:
- pick random sample sites by dividing the field into a grid using measuring tapes and using a random number generator to select coordinated
What are the three types of non random sampling
- systematic
- opportunistic
- stratified
What is systematic sampling
- samples are taken at fixed intervals
- e.g. quadrats placed along a transect from an area of shade to the middle of the field
What is opportunistic sampling
- when the samples are chosen by the investigator
- used because it is simple to carry out, but data will be biased
What is stratified sampling
- when different areas in a habitat are identified and sampled separately in proportion to their part of the habitat as a whole
What is species richness
- number of different species in an area
- higher number of species, the greater the species richness
How is species richness measured
By taking random sample of a habitat and counting number of different speices
What is species evenness
- A measure of the relative abundance of each species in an area
- the more similar the population size the greater the species evenness
How is species evenness measured
Measured by taking random samples of a habitat and counting the number of individuals of each different species
What is Simpson index of diversity used for
Used for measuring diversity
Simpson’s index of diversity is always….
A value between 0 and 1
- the closer to 1 the index is, the more diverse the habitat
- the greater the species richness and evenness the higher the number
