4.2.1: Biodiversity Flashcards
Biodiversity
the variety of life on earth/of species in an environment.
Types of biodiversity
- Species
- Habitat
- Genetic diversity
Species
Two individuals which can interbreed to produce fertile offspring; basic units of biological classification.
Types of non-random sampling
- Stratified
- Systematic
- Opportunistic
What is stratified sampling?
Population divided into strata (sub-groups) e.g. male/female. Random samples then taken from each group.
What is opportunistic sampling?
Uses organisms which are conveniently available e.g. trapping
What is systematic sampling?
Different areas within a habitat are identified and sampled separately, e.g. belt transect.
Methods of sampling living organisms
1) Kick sampling
2) Sweep netting
3) Collecting from trees
4) Longworth trap
5) Pitfall trap
6) Cover trap
7) Water trap
8) Tullgren funnel
9) Light trap
10) Mark-release-recapture
Genetic biodiversity
Differences between individuals of the same species
Habitat biodiversity
Range of habitats in which a species lives
Species biodiversity
Difference between species (e.g. functional differences of bacteria involved in decay and those involved in digestion)
What does a low Simpson’s diversity index mean?
Habitat has low biodiversity
Environment less stable, less able to withstand change
Information needed to calculate Simpson’s index
Number of individuals of all species in area being sampled (100% cover for plants)
Identify all species present
Species richness
Number of different species in area
Species eveness
How close in numbers each species in area is
High Simpson’s index
Area is biodiverse
More stable
Able to better withstand change
Gene pool
Distribution of different alleles in a population
Gene
Length of DNA which codes for a specific protein
Allele
Variation of a gene
Factors which increase genetic biodiversity
Mutation
Interbreeding between different populations
Factors which decrease genetic biodiversity
- Selective breeding
- Rare breeds
- Captive breeding
- Cloning
- Natural seletion
- Genetic bottle necks (only a few survive an event)
- Founder effect (small no. create new population)
- Genetic drift (some alleles will be completely lost naturally)
Polymorphic genes
Genes with more than 1 allele
Factors affecting biodiversity
- Deforestation
- Agriculture –> monoculture
- Climate change
- Humans: pollution, hunting, introduction of new species (cane toad to Australia)
Keystone species
A species which plays a critical role in the ecological community
In situ conservation
Conservation of species in their natural habitat
Ex situ conservation
Conservation of species outside of their natural habitat
Pros of in situ
✔︎ Species will have all necessary resources
✔︎ Cheap
✔︎ Bigger breeding populations can be kept
✔︎ Species will have more space
✔︎ Species will continue to evolve
Cons of in situ
✘ Environment may need restoring
✘ Hard to control poaching
Cons of ex situ
✘ Small gene pool
✘ Often, cannot release = not adapted to disease, have not learned to hunt, cannot interbreed with wild population, habitat may have been totally destroyed
Spearman’s rank results
Between 0 and 1
Higher = stronger correlation (less spread of results)
How to communicate the results of stats tests
1) Find critical values
2) Comment on significance (i.e. above critical value)
3) Comment on probability (p= 0.0.5 –> 5% probability that correlation due to chance)
d (Spearman’s)
Rank difference
n (Spearman’s)
Number of species
N (Simpson’s)
Total number of individuals found
n (Simpson’s)
Number of individuals of a species found
Why conserve species? (economic reasons)
- Regulation of atmosphere and climate
- Formation/fertilisation of soil
- Reducing soil depletion
- Recycling of nutrients (carbon, nitrogen)
- Crop pollination
- Possible sources of medicines
Why conserve species? (ethical & aesthetic reasons)
- Enjoyment of nature –> wellbeing
- Every organism has right to survive and live where they adapted to live
- Physical, intellectual, emotional health
How does the founder effect decrease genetic biodiversity?
- Small number of individuals create a new colony that is geographically isolated from the original
- Increased prevalence of diseases caused by recessive alleles
How does genetic drift decrease genetic biodiversity?
- Which alleles are passed from parent to offspring is random
- Frequency varies but some alleles are lost forever
How does a genetic bottleneck decrease genetic biodiversity?
• Genetic bottleneck: only a few individuals within a population survive an event or change
How does natural selection decrease genetic biodiversity?
• Only individuals with advantageous alleles survive to reproduce
Similarities between the founder effect and genetic bottlenecking?
- Both followed by genetic drift which results in change of allele frequencies
- Initially, genetic biodiversity is lost
- Both involve small numbers of individuals breeding with each other
- Both may result in a new population carrying alleles that are unlikely to be representative of the original group
Differences between the founder effect and genetic bottlenecking?
Bottlenecking involves individuals dying
The founder effect involves ecological separation of individuals
