Biodiversity Flashcards
(40 cards)
What does biodiversity refer to?
Variety of organisms in an area
What are the levels of biodiversity?
Habitat diversity = number of habitats
Species diversity = number of species and individuals in each species
Genetic diversity = variation in alleles within population of a species
What does high genetic diversity allow for?
Better adaptation to changing environment and resistance to disease
What is species richness and how is it quantified?
Total number of different species in a habitat
quantified by taking random samples and counting the species present with
a high species richness indicates greater diversity
What is species eveness and how is it quantified?
Comparison of numbers of individuals of each species in a community
measured by taking samples and counting individuals of each species with
more even abundances meaning higher species evenness and diversity
What does random sampling allow?
Avoid bias and ensure samples are representative of whole population
Outline the method of random sampling?
1) randomly generate coordinates across area
2) collect samples from random coordinates
3) repeat this several times
4) analyse the data collected
What is the purpose of each stage of random sampling?
Randomly generate coordinates = prevents sampling bias by removing human involvement in choosing samples
Collect samples from random coordinates = gives us samples representative of population
Repeat several times = gives us large sample size minimising effect of chance
Analyse data collected = lets us identify any relationships
What are the 5 techniques of sampling animals?
1) pooter
2) sweep net
3) pitfall trap
4) tree beating
5) kick sampling
What is a pooter and how does it work?
Samples small insects by sucking air containing insects into a plastic container via a tube
What is a sweep net and how does it work?
Samples insects in long grass or air where net is swept in a ‘figure of 8’ motion
What is a pitfall trap and how does it work?
Samples small ground-crawling animals e.g insects by catching in hidden trap
What is a tree beating and how does it work?
Samples invertebrates living in tree or bush by shaking or beating tree to dislodge insects onto a white sheet below
What is a kick sampling and how does it work?
Samples river organisms by kicking river bank and catching organisms downstream in a net
What do quadrats typically sample?
Plants or animals that don’t move much (non-motile)
What is a frame quadrant and how does it work?
Square frame divided into grid where type and number of species within each section of quadrat is recorded
What is a point quadrant and how does it work?
Frame with horizontal bar through which pins are pushed at set intervals to touch ground and each species pin touches is recorded
How do you calculate species density per quadrat?
Number of individuals of a species in a 1 m2 quadrat
How do you calculate species frequency per quadrat?
number of squares in quadrat species found ÷ total of number of squares in quadrat x 100
What does non random sampling involve?
Selection based on specific criteria or patterns and the sample is not chosen at random
What is the difference between random and non random sampling?
Random sampling removes human bias in sample selection improving reliability whereas non-random sampling doesn’t use random selection so is prone to bias
What is opportunistic sampling?
Uses conveniently available organisms so may not be representative of the population
What is stratified sampling?
- divides population into subgroups (strata) based on characteristic
- random sample taken from each subgroup/stratum
- number of samples taken in each stratum proportional to size of stratum
What is systematic sampling?
Samples different areas in habitat separately at regular intervals to avoid bias
