genetic diversity and adaptation Flashcards
What is genetic diversity?
the total number of different alleles in a population
What advantage does high genetic diversity provide?
the stability to adapt to a change in the environment, allows natural selection to occur
Explain how natural selection results in the development of new characteristics
mutations -> new alleles
some alleles provide a selective advantage, meaning they are more likely to survive and reproduce
the offspring receive the allele and pass it to next generation, allele frequency increases
What is directional selection?
individuals with phenotypes suited to the environment will survive and pass on alleles, the mean of population will shift towards these phenotypes
When does directional selection occur?
when there is a change to the environment
Give an example of directional selection
Antibiotic resistance.
What is stabilising selection?
Individuals closest to the mean are favoured, any with new characteristics are selected against. Low genetic diversity
When does stabilising selection occur?
when the environment remains the same
Give an example of stabilising selection?
birth weight
What are 3 types of adaptation?
behavioural (actions) , physiological (body processes) and anatomical (body structure)
What is an allele?
different form of the same gene, found at the same locus
How has the use of antibiotics led to antibiotic resistant bacteria being contracted in hospitals?
some bacteria have allele for resistance
non-resistant die/antibiotics is selection pressure
more antibiotics used in hospitals/high frequency of resistance allele
