Lecture 15: inbreeding and genetic diversity can research 25. 1. Two elements: intraspecific variation or gene diversity interspecific variation or species diversity. Genetic considerations: small population size + interbreeding. Demographic considerations: immigration/emigration + connectivity: gene flow. Genetic consequences of small population size loss of genetic diversity by: population bottlenecks, genetic drift founder effects take alleles from large pop and now are in small pop. inbreeding inbreeding depression fixation of deleterious genes. -> only heterozygote produce heterozygote offspring but only 50% of the time. Going from parental to g4 to g5, shrink heterozygous and increase homozygous individuals. -> increases homozygosity. in small pops, hetero wipe out quicker. -> does not cause evolution because allele frequencies do not change in the population as a whole. inbreeding changes genotype frequencies but not af. Evolution can occur by mutation or immigration where pop structure changes. Inbreeding depression: decline in average fitness in a population that takes place when homozygosity increases and heterozygosity decreases.