Chapter 11 - Biodiversity Flashcards
Why is biodiversity important?
Essential to maintaining a balanced ecosystem. All species are interconnected and interdependent, all rely on one another.
What are the 3 levels of measuring biodiversity?
Habitat biodiversity
Species Biodiversity
Genetic Biodiversity
What is habitat biodiversity?
The number of different habitats within a given area.
What is species biodiversity?
2 components;
Species Richness - number of different species living within an area
Species Evenness - a comparison of the numbers of individuals of each species living within a community.
What is genetic biodiversity?
Refers to the variety of genes that make up a species. Can lead to differing bc characteristics.
What is sampling?
Taking measurements of a limited number of individual organisms present in a particular area. Can be used as ab estimation.
What is random sampling?
Selecting individuals by chance. There is an equal likelihood for whatever organism to be chosen.
How to carry out random sampling?
Mark out a grid on the grass using 2 tape measures laid at right angles
Use a random number generator to determine the x coordinate and the y coordinate on the grid.
Take a sample at the coordinates generated.
Repeat
What are the 3 non random sampling methods?
Opportunistic
Stratified
Systematic
Disadvantages of opportunistic sampling?
May not be representative as it uses organisms that are conventiently available.
What is stratified sampling, how can it be carried out?
Divided into subgroups (strata) based on particular characteristics. Eg separated into males and females. A random sample is then taken from each strata proportional to its size
How can systematic sampling be carried out?
Different areas within an overall habitat are identified and they’re sampled separately. Nah be used to see how plant species change as you move away from the sea
Often carried out using a line or belt transect
Why so sampling never fully reliable?
Sampling Bias- can be reduced by choosing random sampling.
Chance - where the organisms selected may not be representative of the whole area. Can be reduced by using a larger sample size.
What is a pooter used for?
Catching small insects, sucking on a mouth piece means that insects are picked up and held in a holding tube
What are sweep nets used for?
Used to catch insects in areas of long grass
What are pitfall traps used for?
Used to catch small crawling invertebrates such as beetles, spiders and slugs. A hole is dug into the ground and the insects fall into it
What is tree beating used for?
Used to take samples of invertebrates living in a tree or Bush. Large white cloth stretched out under the tree. Tree is shaken, insects fall onto sheet where they can be studied.
What is kick sampling?
Used to study organisms living in a river. River bank / bed is kicked for a short period of time to dislodge the substrate. A net is held downstream for a period of time to capture any organisms released into the flowing water.
What are plants normally sampled with?
Quadrat
What are the 2 types of quadrat?
Point quadrat and frame quadrat.
How can you measure species richness?
Using a variety of techniques. A list of species should be compiled and a total number of species can then be calculated.
3 ways to estimate population when using frame quadrats?
Density
Frequency
Percentage Cover
How can population be estimated?
Using a capture-mark-release-recapture method
Why is maintaining biodiversity important?
Ecological reasons
Economic reasons
Aesthetic reasons (eg protecting landscapes)
What are in situ ways of maintaining biodiversity?
Marine conservation zones
Wildlife reserves
What are ex situ ways of maintaining biodiversity?
Zoos, seed banks, and botanic gardens
Captive breeding programmes
