Biodiversity Flashcards
Define biodiversity…
The variety of living organisms present in an area.
What are the 3 levels that biodiversity can be studied?
Habitat, species, genetic.
What is habitat biodiversity?
The number of different habitats found within an area. Each habitat can support a number of different species eg. Meadow, woodland, streams, sand dunes. Habitat diversity is in correlation with species biodiversity.
What are the 2 components of species biodiversity?
Species richness and species evenness.
What is species richness?
The number of different species living in a particular area.
What is species evenness?
A comparison of the numbers of individuals of each species living in a community.
What is a community?
The population of a particular habitat.
What is genetic biodiversity?
The variety of genes that make up a species.
What does greater genetic biodiversity within a species allow for?
Better adaption to a changing environment and more likely to contain individuals who are resistant to disease.
What is sampling?
Taking measurements of a limited number of individual organisms present in a particular area.
What can sampling be used to estimate?
The number of organisms (abundance), particular characteristics of a species to be able to make generalisations.
What are the 2 ways sampling can be done?
Random and non-random.
What is random sampling?
Selecting individuals by chance, each individual in a population has an equal chance of selection.
Name 2 ways to randomise selection…
Random number tables, computers.
What is non-random sampling?
The sample is not chosen at random, an alternative to random sampling.
What are the 3 methods of non-random sampling…
Opportunistic, stratified and systematic.
What is opportunistic sampling?
The weakest form of sampling as it is not representative. Uses organisms that are conveniently available.
What is stratified sampling?
Dividing populations into a number of strata (sub-groups) based on a particular characteristic. A random sample is taken from each sample proportional to its size.
What is systematic sampling?
Different areas within an overall habitat are identified and sampled separately.
What is the difference between a line and belt transact?
A line transact involves making a line along the ground between 2 poles and sampling at specified points. A belt transect occurs between 2 parallel lines and sampling occurs at specified locations.
What reduces sampling reliability and how can this be resolved?
Sampling bias - random sampling
Chance - large sample
Name 5 methods of sampling animals…
Pooter, sweep nets, pitfall traps, tree beating and kick sampling.
Describe and explain the 2 types of quadrat…
A point quadrat consists of a frame containing a horizontal bar, a set intervals a pin can be pushed through. A frame quadrat consists of a frame divided into a grid of equal sections.
What are 3 ways a frame quadrat can be used?
Density in a square, frequency of square, percentage cover.
How is an animal population size estimated?
Capture-Mark-Release-Recapture