genetic diversity and adaptations Flashcards
What is genetic diversity?
Number of different alleles of genes in a population
What are alleles and how do they arise?
● Variations of a particular gene→ different DNA base sequence
● Arise by mutation
What is a population?
A group of interbreeding individuals of the same species
Explain the importance of genetic diversity
● Enables natural selection to occur
● As in certain environments, a new allele of a gene might benefit its possessor
● By resulting in a change in the polypeptide (protein) coded for that positively changes its properties
● Giving possessor a selective advantage (increased chances of survival and reproductive success)
What is evolution?
● Change in allele frequency (how common an allele is) over many generations in a population
● Occurring through the process of natural selection
Allele frequency
Over many generations, [named] allele increases in frequency in the population
vDescribe 3 types of adaptations
● Anatomical - structural / physical features that increase chance of survival
● Physiological - processes / chemical reactions that increase chance of survival
● Behavioural - ways in which an organism acts that increase chance of survival
Directional selection and its effect on population
*Organisms with an extreme variation of
a trait.
*change in environment introduced
*increased frequency of organisms with allele for extreme trait.
*normal distribution towards the extreme trait
Stabilising selction and its effects on population
*organisms with average/modal variaton of trait like normal babyweight.
*no change in environment introduced
*Normal distribution curve similar,
less variation around the mean
Natural selection
*mutations result in diffrent allles allowing increasing gen diversity allowing natural selection to occur
