4.2 Biodiversity Flashcards
What is the definition of biodiversity?
Variety of organisms present in one area
What is the definition of a species?
Group of organisms with very similar appearance,anatomy,physiology,biochemistry and genetics who can interbreed to produce fertile offspring
What is the definition of a community?
All the living organisms in a habitat
What are the three levels of biodiversity?
Habitats- Number of habitats in one area
Species richness
Species evenness
Genetic
What is the difference between species richness and species evenness?
Richness- Number of species in an area
Evenness- Number of each species
Why measure biodiversity?
- Important for conservation
- Before a major project
What is sampling?
- Taking measurements of a limited number of individual organisms present in an individual area
What can sampling be used for?
- Used to measure abundance
- Used to measure a particular characteristic and workout an average
- Allows for generalisations and estimates where it would be impossible to count
What is random sampling?
Selection of individuals by chance
No involvement in location decision
What examples of non random sampling are there?
Opportunistic- Uses organisms which are convenient
Stratified- Populations are divided into subgroups based on a particular characteristic
Systematic- Different areas in a habitat are identified and the sampled separately
Why is sampling never entirely representative and how is this reduced?
Sampling Bias- Selection process may be bias due to choosing particular areas- Reduced by random sampling
Chance- Organisms by chance may not be representative of whole population-reduced by large sample size
How is plant abundance estimated?
ACFOR scale
What us a point frame quadrant?
Each plant that touches a pin is recorded
What equipment can be used to sample insects and other small animals?
- Pooter- catch insects by sucking into pot
- Sweep nets- In large areas of grass
- Pitfall traps - Hole is dug which insects cannot crawl out of
- Tree beating- large white cloth is suspended underneath tree then a tree is beaten
-Kick sampling- for river organisms,kicking the river bed
How is capture-recapture conducted?
- Capture sample of animals and count (C1)
- Mark each individual
- Release and leave traps for set periods of time
- Number captured the next time (C2), Number marked (C3)
What is the equation for capture-recapture?
Total population = (C1 x C2) / C3
What is Simpsons diversity?
The measure of diversity in a habitat
Accounts for both species richness and evenness
What is the formula for calculating species richness and evenness?
D= 1- (sum of (n/N) ^2
Where:
n= number of individuals of each species
N= total number of individuals