Speciation

• Allele frequency is affected by selection from environmental change
• Speciation is the process of a new species forming, populations are separated reproductively by different factors causing population gene pools to diverge
• Adaptive radiation is where a species in a local area will develop different phenotypes than those in another area due to selection pressures specific to each environment
• Genetic drift is random variation in frequency of genotypes, often occurring in smaller populations where allele frequencies are affected more dramatically
• Genetic drift may occur in founding populations where, a limited gene pool becomes even smaller due to the small population leading to different gene frequencies in populations
• In speciation, a large interbreeding population will be separated into different breeding groups, random mutations in each sub group leads to new variation between populations, those with favourable alleles survive and reproduce, passing on their alleles to offspring, natural selection occurs, favouring certain genotypes and increasing allele frequency, over many years, the two gene pools are reproductively isolated and no longer the same species as they cannot interbreed
• Speciation can be allopatric where two populations are separated by a geographical barrier such as an earthquake
• Speciation can be sympatric where populations are in the same local area but a different barrier separates populations such as breeding seasons or non compatible sexual organs
• Hybrid sterility is where two different species breed, homologous chromosomes dont form pairs leading to no offspring or offspring which cannot successfully reproduce to create viable offspring