Mammals have evolved in ways that are beneficial for them, ensuring their survival and turning them into the beings that we are familiar with today. Species, organisms which have always had features in common, evolve through four main forces: gene flow, genetic drift, mutations, and natural selection.
Genetic drift involves a population, a group of the same species that lives in the same geographical and temporal location. Genetic drift causes changes to occur in members of a population through random events within their geographic region. For example, if a tornado hit one area and killed more brown eyed squirrels than blue eyed ones, brown eyed squirrels would have more genetic material in the population and would …show more content…
In the case of the industrial Revolution in London, they found that the trees just outside of London were covered in the soot and dirt from factories. Moths that were brown and could blend into the new color of the fauna were less likely to get eaten than their more colorful counterparts, which could be easily seen by prey. Grey moths were able to reproduce more, and thus passed on their advantageous grey-coloring trait.
Isolating mechanisms are factors which stop two members of the same species from interbreeding. This prevents mutations which may be detrimental and could potentially cause the organism to be sterile and unable to pass on its genetic material. Isolating mechanisms can either affect the ability of organisms to conceive, affect the ability of an organism to carry an embryo to term, ensuring variation within a population.
Speciation also ensures variation within a population, thus increasing the species’ chance for survival and reproductive success. Speciation allows for reproductive success and for an organism to carry an embryo to full term. These changes evolve as a result of genetic drift or selection. Modes of speciation involve: peripatric (a small outlying population isolated just on the peripheral of a larger population of the same species), allopatric (geographically isolated populations), parapatric (continuously distributed population i.e. they have to migrate a lot due to random geographical