Adaptation and Taxonomy Flashcards
What happens to the mean in directional selection?
It moves in the direction of the favourable extreme
What happens to the mean in stabilising selection?
It remains the same as the populations loses its extremes and stabilises
What does directional selection favour?
Extremes
What does stabilising selection favour?
Middle range
What causes directional selection?
An environmental change
What happens in response to directional selection in response to an environmental change?
Only individuals with favourable extreme characteristics can survive and reproduce and therefore pass on the allele for the favourable characteristic
Why does stabilising selection stabilise?
Because extreme individuals cannot survive, reproduce and pass on their alleles to future generations
Give an example of stabilising selection
Birth weight
Give an example of directional selection
Antibiotic resistance
What is genetic diversity?
The number of different alleles of a gene in a population
What does a larger gene pool indicate?
Greater genetic diversity
What does natural selection result in?
Species being better adapted to their environment
How can a species adapt to its environment?
Anatomically, Behaviourally, Physiologically
How does natural selection take place?
Individuals with beneficial alleles and phenotypes are more likely to survive, reproduce and pass on the beneficial alleles to the next generation
What is evolution?
The change in allele frequency over time
How does evolution take place?
It happens as a result of a beneficial allele mutation undergoing differential reproductive success over a long period of time resulting in a changed allele frequency
What is a species?
Organisms that can breed to produce fertile off springs
Why is courtship behaviour used?
It increases the chance of successful mating
How does courtship behaviour increase the chance of successful mating?
- Recognition of the same species- Stimulates gamete release- Recognise opposite gender- Indicates sexual maturity
How does phylogenetic classification work?
It arranges species into groups based on evolutionary relations with each level in the heir-achy being a taxon
What is the order of phylogenetic classification?
D,K,P,C,O,F,G,S
What is the specific oder of phylogenetic classification?
DomainKingdomPhylemClassOrderFamilyGenusSpecies
What is the binomial naming system?
A universal way of classifying organisms, it uses Genus species
What is phylogenetics?
Comparing the relationships between organisms in a heirachy
How can phylogenetics be carried out?
By immunology or genome sequencing
How are phylogenetics carried out by immunology?
Comparing different organisms ability to form anibody-antigen complexes. Organisms that can form the same antigen-antibody complexes are very closely related
How are phylogenetics carried out by genome sequencing?
The base sequences of different organisms are compared, higher % match = close relation
Within a species, what causes genetic diversity?
Alleles
A haploid human cell contains how many chromosomes?
23
What is an argument against selective breeding?
It reduces genetic diversity within a population
Define taxonomy
The study of classification
Phylogenetics tells us what about an organism?
The evolutionary relationships of that organism
