4.2.1 Biodiversity Flashcards
(18 cards)
Define biodiversity
A measure of variability found in the living world, at the ecosystem/habitat, species and genetic levels.
What are the 3 components of biodiversity?
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
Describe the 2 parts of species biodiversity
- Species richness = the number of different species/populations
- Species eveness = The relative abundance of each species within a community.
What are the 4 methods of sampling
- Random
- Opportunistic
- Stratified
- Systematic
Describe 3 methods of counting/estimating abundance of plants
- Working out the frequency of plant in quadrat
- Percentage occurance
- Percentage cover
Describe the AFCORN scale
- The scale is used to indicate the occurance of plants
A = abundant
C = common
F = frequent
O = occasional
R = rare
N = none
Describe 2 types of quadrat
Point quadrat:
- Useful for longer vegetation
- Counts plants touching pins
- However it overestimates tall thin leaved plants that may touch the pins more than once
Frame quadrat:
- Consists of a square frame divided into a grid of equal sections
Describe the main 5 animal sampling methods
- A pooter is used to catch small insects. By sucking on a mouth piece, insects are drawn into the holding tube via the inlet tube. To prevent insects being sucked into the mouth their is a filter before the mouth piece.
- Sweep nets can be used in areas of long grass to catch insects.
- Pitfall traps are used to catch small, crawling invertebrates. This involves digging a hole into the ground which they then fall into. Their is a cover on top to prevent rain from entering.
- Tree beating is another technique used to take samples of inertabrates living in a tree or bush. This involves a lrage white cloth being put under a tree and then the tree is shaken.
- Kick smapling is used to sample freshwater organisms.
Describe the capture, recapture method
- Mark animals in a way that does not harm them or ruin their camoflague against predators
- Release the individuals and wait long enough so that they can redistribute throughout the population but not too long that some die
- Then capture the same ammount of animals as before and record how many of the sample are marked
- Use the ratio to work out the total population
How do you calculate biodiversity
- To calculate biodiversity the Simpson’s Index is used
- N = the total number of organisms of all species
- n = the total number of organisms of a particular species
- 0 represents no diversity and 1 represents infinite diversity
Explain the importance of genetic diversity
- Within species individuals have little variation in DNA.
- The difference in alleles between among individuals of a species creates genetic biodiversity within the species.
- The more alleles in a population the more genetically diverse the population will be.
List the factors that affect genetic diversity
- Mutations (increase)
- Interbreeding (increase)
- Selective breeding (decrease)
- Captive breeding programes (decrease)
- Artificial cloning (decrease)
- Natural selection (decrease)
- Genetic bottlenecks = where few individuals in a species survive an event or change. (decrease)
- The founder effect = where a small number of individuals create a new colony (decrease)
List the human impacts on biodiversity
- Deforestation
- Agriculture
- Climate change
What are the 3 main categories of reasons for maintaining biodiversity?
- Aesthetic
- Economic
- Ecological
Define conservation
Conservation is the name given to the preservation and careful management of the environment and of natural resources.
What are the 2 types of conservation?
- In situ conservation (within the natural habitat)
- Ex situ conservation (out of the natural habitat)
Describe in situ conservation
- In situ conservation takes place within an organisms natural habitat.
- This maintains the genetic diversity of the species and the evolutionary adaptations that allow a specie to adapt continually to changing enviornments.
- By allowing the endangered species to interact with other species it prevents interdependent relationships from forming so interlinked species can also be protected.
Describe examples of in situ conservation
Wildlife reserves:
- Controlled grazing
- Restricting human access
- Controlling poaching
- Feeding animals
- Reintroduction of species
- Culling or removing invasive species
- Halting sucession (when early colonising species are replaced over time until a stable, mature population is acheived)
