Explain each of the following modes of evolution in a population. for each one, describe the cause of change in the genetic makeup of a population and how the population evolves as a result of that change, and provide 1 "real world" examples of the process in action:
natural selection
genetic drift
gene flow
sexual selection

Genetic Drift: Any eent that end the life of a specie or that in some other way allow only a random subset of a population, can cause random changes in frequencies of alleles. The process by wich fortuitous events changes allelic frequencies is called genetic drift. Example: a population of 20 hamsters where the frequency of the B allele for black fur is 0.50 and the frequency of alle b for fur brown is 0.50.  If all hamsters of the population will cross over to produce another population of 20 animals, the frequencies of the 2 alleles would not change in the next generation.  But, instead, if it is allowed only 2 random hamsters to cross over, the frenquencies can be very different in generation 2.  

Gene flow: the allelic movement betwen poblations of  species, is known as gene flow. When a individual moves from one population to another, the alleles are transfered from one genic pit to another.  The mandrels, individuals move often to new populations.   The females mate to the dominant males.  Young males usually leave the population and will jojin another.  So, the male descendants carry the allele of the geen pool of other population.

Natural selection: Differential reproduction of genotypes of a biological population which means, There are organisms that reproduce and the progeny inherits characteristics of the parents.  The members of the populatiosn with less adapted characteristics will be more likely to die. And the members better adapted will survive.

Sexual selection: is the ability of an organism to achieve or to copulate with a partner. This achievement and ability depends on the couple choosing the best individual or presenting the best characteristics so that their progeine adapts the best to the world.