Genes and evolution Introduction to genetics

mice different coat colors

a population of organisms evolves when inherited trait becomes more common or less common on time. instance, mice living on island single population of mice: white fur, gray. if on generations, white mice became more frequent , gray mice less frequent, color of fur in population of mice evolving. in terms of genetics, called increase in allele frequency.

alleles become more or less common either chance in process called genetic drift, or natural selection. in natural selection, if allele makes more organism survive , reproduce, on time allele becomes more common. if allele harmful, natural selection makes less common. in above example, if island getting colder each year , snow became present of time, allele white fur favor survival, since predators less see them against snow, , more see gray mice. on time white mice become more , more frequent, while gray mice less , less.

mutations create new alleles. these alleles have new dna sequences , can produce proteins new properties. if island populated entirely black mice, mutations happen creating alleles white fur. combination of mutations creating new alleles @ random, , natural selection picking out useful, causes adaptation. when organisms change in ways them survive , reproduce. many such changes, studied in evolutionary developmental biology, affect way embryo develops adult body.