Biodiversity, 4.2 Flashcards
Define species
A group of organisms that interbreed to produce fertile offspring
Define habitat
Where an organism lives
Define biodiversity
Variations in the living world eg gene, species and habitats
Define genetic biodiversity?
Measure of genetic variation between individuals belonging to the same species
What is the risk of low genetic biodiversity?
Extinction
Define species biodiversity
How many different species in an area and how many individuals of each species there are
Define habitat biodiversity
Different habitats present in an area
What do we need to do to find biodiversity?
Compare different sites. Compare same areas at different times
What is random sampling?
Divide habitat into coordinates and use random number generator. Quadrats placed at random. Minimum of 10 samples
What are the advantages of random sampling?
Ensure data isn’t biased
What are the disadvantages of random sampling?
May not cover all of the habitat equally. Species may be missed.
What are different types of non-random sampling?
Opportunistic. Stratified. Systematic.
What are the advantages of Opportunistic sampling?
Easier and quicker than random sampling
What are the disadvantages of Opportunistic sampling?
Data may be biased leading to an overestimation in biodiversity
What is Opportunistic sampling?
Use prior knowledge
What is stratified sampling?
Divide a habitat into areas that appear to differ
What are the advantages of stratified sampling?
Ensures that all types of an area are studied and represented.
What are the disadvantages of stratified sampling?
Lead to an over representation of some areas
What is systematic sampling?
Samples are taken at fixed intervals across a habitat using a transect
What are the advantages of systematic sampling?
Useful when the habitat shows a gradient
What are the disadvantages of systematic sampling?
Only species along transect line so may be an underestimation of biodiversity
What are quadrats?
Square frames used to define a set area for sampling
What is a line transect?
A line drawn through an area to be examined. Move along line and record species at intervals
What is a belt transect?
Quadrats at regular intervals along the line. Shows density of species as well as what is there.
How do you sample animals by observation?
Can look for things such as footprints or droppings.
How do you sample animals by a sweep net?
Sweep net in wide arcs so insects become trapped. Empty onto a white sheet and use a pooter