18 populations and evolution Flashcards
what is a gene pool?
all the alleles of all the genes of all the individuals in a population at a given time
what is allelic frequency?
the number of times an allele occurs within the gene pool
what is the hardy-weinberg principle?
calculate the frequencies of the alleles of a particular gene in a population
what does hardy-weinberg principle assume?
the the proportion of dominant and recessive alleles of any gene in a population remains the same from one generation to the next
how can proportion of alleles remain the same from one generation to the next?
- no mutations
- population is isolated
- no selection
- population is large
- mating is random
what genetic factors cause variation?
- mutations
- meiosis
- random fertilisation of gametes
what is selection pressures?
the environmental factors that limit the population of a species
what three factors does natural selection depend upon?
- organisms producing more offspring that can be supported by the environment
- genetic variety within the populations of all species
- a variety of phenotype that selection operates against
what is speciation?
the evolution of new species from existing ones
what is allopatric speciation?
the form of speciation where two populations become geographically isolated
what is sympatric speciation?
form of speciation that results within a population in the same area leading to them become reproductively separated
