4.4 Flashcards
Genetic diversity
No of different alleles of gene in population
Alleles
Variation of particular gene on same locus different dna base seq
Arise by mutation
Population
Group of interbreed individuals of same species
Importance of genetic diversity
Giving possessor a selective advantage increased chances of survival and reproductive success
enables natural selection to occur
As in certain envi new alleles benefit possessor
By resulting in change in polypeptide coded for that positively changes its properties
Giving possessor selective advantage increased chance of survival and reproductive success
evolution
change in allele frequency over many generations in a population
occurs through process of natural selection
principles pf natural selection in the evolution of populations
random gene mutations = new alleles of a gene
in certain environments the new allele may benefit the possessor as organism has a selective advantage
so possessors more likely to survive and reproduce success
advantageous allele inherited by members of the next generation
over many generations allele increases in frequency in the population
anatomical
structural and physical features increasing chance of survival
physiological
chemical reactions increasing changes of survival
behavioural
ways an organism acts to increase their chance of survival
directional selection
eg antibiotic resistance in bacteria
organisms with extreme variation of a trait so an increased number of organisms with allele for extreme trait
stabilising selection
human birth weight
organism with average trait has selective advantage so an increased frequency of organism with average traits