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
Why is it advantageous to use tools such as a temperature probe to measure abiotic factors?
Rapid changes can be detected
Reduces the risk of human error
High degree of percision achieved
Data can be stored and tracked on a computer
The diversity of organisms present is usually proportional to the ______ of an ecosystem
Stability.
What are some features of a stable environment
Large numbers of fairly evenly distributed species, in good sized populations.
What is the technique used to calculate biodiversity?
Simpsons index of diversity.
Where N is the total number of all species.
n is the total number of organisms in a particular species.
In a low level of biodiversity, what would the effect of change on an ecosystem be like?
Major, as it’s small and has little variety
What are 2 ways that genetic biodiversity can be increased
Mutations in alleles
Interbreeding - breeding between different species
Name the 7 ways in which genetic biodiversity may decrease.
Selective breeding - Only a few individuals in the population are selected for breeding.
Captive breeding programmes - Zoo’s, small population for breeding
Artificial cloning - Asexual reproduction
Natural selection- Species will evolve primarily into the advantageous allele, so the variations of allele present will decrease.
Genetic bottlenecks - Only a few of a population survive a natural disaster or disease.
Founder effect - Small gene pool start a new colony, separated from rest of the world.
Genetic drift - Random nature of alleles being lost when passed down to offspring.
What is a polymorphic gene
Have more than one allele. I.e. multiple alleles exist for immunoglobulin gene. IA IB and IO
How can proportion of polymorphic gene loci be measured?
Number of polymorphic loci / Total amount of loci
The greater the proportion of polymorphic gene loci, the greater the genetic diversity in that area.
