C11 Flashcards
What is the definition of biodiversity and what are the three levels it can be studied at?
It is the variety of living things in an area. Can be studied at habitat, species, and genetic
Species biodiversity can be split into Species______ and Species _______
Eveness and Richness
What is habitat biodiversity
Refers to the no. Of habitats found in an area, greater the habitat biodiversity, the greater the species biodiversity.
Why is it advantageous to have a high genetic biodiversity within a species
More alleles, more Chance of having the advantageous allele, so species is less likely to contract disease, and less likely to become extinct
A variety of techniques can be used to measure and compare biodiversity in different areas, these are called ________ ________.
Sampling techniques
What is sampling
Sampling means taking measurements of a limited no. Of individual organisms present in an area in order to estimate the overall number in an area.
Explain how you could carry out a random sample
- Mark out grid using tape measures placed at right angles, use a random no. Generator to decide which coordinates to use on the X and Y axis.
- Take a sample of each of the coordinates pairs generated
Name and briefly explain the 3 non random sampling methods.
Opportunistic - Weakest form of sampling, may be representative of population. Uses organisms that are available at the time of sampling.
Stratified - Population divided into strata, based on characteristics I.e. Gender. Random sample is then carried out proportional to its size.
Systematic - Diff. Areas within an overall habitat are identifies. They are the samples separately. Often carried out using a line or belt transect.
What’s sampling bias?
Selection process on where to sample may be bias, e.g. may pick an area with loads of diversity that is not representative of the population.
What are the 5 tools that can be used to sample animals.
Pooter, Sweep net, Pitfall trap, Tree beating, Kick sampling.
Explain a point quadrat and a Frame quadrat.
Point - Consists of a Frame containing a horizontal bar at set intervals a pin is pushed through the bar, any plant touching the pin is recorded.
Frame - Consists of a square frame divided into a grid of equal sections. The type, and number of species within the sections of the quadrat are recorded.
Quadrat should generally be used as a tool during random sampling.
What are the 3 main ways a frame quadrat can be used?
Density - If large plants can be seen, Count the number of them in a 1m by 1m quadrat. This gives the density per square meter.
Frequency - Used when individual no. Of species are hard to count. Calculate how many squares occur in.
Percentage cover - Estimating the amount of percentage that a certain thing takes up.
How do you work out the total population of an organism.
Total Pop = Mean value per square meter x total area
What is the method to estimate animal population size, and why is it difficult to measure the population size of animals?
Capture - Mark - Release - Capture
Compared marked individuals with unmarked, population size can be estimated, greater marked ones recaptured, smaller the population.
Hard to measure as animals are always moving.
What do scientists also measure at each sampling point?
Abiotic factors such as wind, PH, light intensity, temperature, oxygen content in water , relative humidity
