Biodiversity Flashcards
What is intraspecific or genetic diversity?
Variety of alleles within a species.
What are the three levels of biodiversity?
- Genetic/Intraspecific
- Interspecific/Species
- Ecosystem
What is interspecific or species diversity?
Variety of species within a community/habitat
What is ecosystem diversity?
Variety of habitats within an ecosystem.
In genetic diversity what are the two types of variation?
Continuous variation and Discontinuous variation.
How do you quantify genetic diversity?
Measuring the number of different alleles present within a species
What are the characteristics of continuous variation?
- Have no distinct categories
- Tends to be quantitative; each category continues from the last
- Are polygenic; determined by a large number of genes
- Significantly affected by the environment
Give examples of continuous characteristics in humans.
Height, hair colour, muscle efficiency.
What are the traits of the characteristics of discontinuous variation?
- Distinct categories
- Tends to be qualitative; no overlap between categories
- Controlled by one gene or a small number
- unaffected or slightly affected by the environment
Give Examples of discontinuous characteristics in humans.
Blood groups, detached ear lobes, straight or bent thumb
How do you study the cause of variation in humans?
Twin studies; studying the variation in characteristics between identical twins in comparison to the variation of the same characteristics in non-identical twins or siblings.
What is biodiversity?
The variability among living organisms from all sources. Diversity between species, within species and of ecosystems.
How do twin studies show whether characteristics are due to genetic or environmental factors?
Because twins are genetically identical, any differences between them, are probably due to environmental factors.
How is high genetic diversity the basis of survival and evolution of a species?
If a species has high genetic diversity, there will likely be individuals with the required characteristics to survive a change in environment. If low genetic diversity, a species is more likely to become extinct due to environmental changes.
What are three main causes of low genetic diversity?
Genetic bottlenecks, The founder effect and selective breeding
What causes genetic bottlenecks and what are they?
When a population is drastically reduced in size due to a catastrophe or change in environment. The remaining individuals will have a smaller range of alleles, so when they reproduce, there will be reduced genetic diversity.
Give examples of genetic bottlenecks
Northern elephant seal
Cheetahs
Golden Hamster
Humans
What is the founder effect?
When small numbers of individuals colonise a new habitat and start a new isolated population, where the individuals have small range of alleles leading to low genetic diversity. Also called a colonisation bottleneck.
What is selective breeding and how does it cause low genetic diversity?
The controlled breeding of animals or plants so that only individuals with certain characteristics can reproduce, reducing the number of alleles in the species resulting in low genetic diversity.
How to measure interspecific diversity?
Taking samples using a transect and or quadrat
What is species richness?
The number of species in a sample
What is species abundance?
The number of individuals of a species population in a community or habitat
What is the Simpson diversity index?
A measure of richness AND abundance.
= N(n-1)/The sum of n(n-1)
Where N is total number of individuals and n is number of individuals in each species.
How can you interpret the Simpson Diversity Index?
The higher the index, the better the species diversity. The lower the index, the worse the species diversity.
