What are the three major mechanisms of evolution differ in how they work

Evolution is the process through which the different organisms advances from having less developed form or the position into a less-perfect form. As, different species go through different pathways in which they attain a new and complex form of mechanism to survive inside a region or given parameters. While, the process of evolution takes place in a three main different forms or ways, or briefly in three different pathways: The natural selection: Species goes through different process in which they deal with the number of obstacles, like the limitation of food resources, having the competition for the shelter and resources etc. During, such a process the species either goes into extinction or they survive for a much longer time then expected. The Genetic flow: The species have a given set of genes or more over genome which they posses for having a specific identity among the diverse form of organisms. The different species may go through the mutations or even may go through the different form of gene losses. As, due to the changes inside the overall environment or the system of the organisms the difference or diversity inside the genome of the organisms may occur. The Genetic drift: The genetic drift is the displacement which causes the changes inside the different species over all existence. For example, lets genetic drift may be termed as the process which is brought by a set of species which are detached from its over all population and it brings change along with variety by introduction of that small population inside the given region.

Mechanisms of Evolution.

Generally an individual do not evolved, the population of individuals in the population actually evolved. The collection of the gene in a population is called gene pools, and it is the factor within the population that is responsible for evolution of population. This gene pool can be altered within the population by mutation, which produces variation in the organism. Thus mutations is the driving force for changes in the gene pool of population.

When population of organisms migrates from one region to another. Assuming they mate with new organisms of the same species, their gene pool is exchanged at fertilization. Thus they contributed new gene to population, This genetic contribution from migration of gene pools i s called Gene flow.

Assuming small population of individual migrated to new area far away from the original location, and are thus geographically isolated, As they interbreed new group of individual evolved, different from their original population, due to variation by mutation. This process is called Gene Drifts. it usually take place in small population, and it depends on random sampling of alleles of individuals in the population.

As individual in the population are exposed to selection pressures, mostly competition for, mating partners, foods, space, effects of diseases, the population of individual are affected. However some organisms in the population may be able to resist these selection pressure, and therefore survive, while those without these characteristic fizzled out of the population. The surviving organisms were the fittest. They must have possessed certain characteristics or gene, which makes them to resist the selection pressure, and therefore survive ahead of the weak ones. Thus they have been naturally selected by nature.

if these continues over many generation, they will pass this traits/gene to their offspring, and with time their population dominated the population. Thus they have emerged or evolved to new species of organism. This is evolution by natural selection by survival of the fittest.