The processes of evolution - Essay Example

ANTH1100 November 25, The definition of the term species remains controversial though it is the most important unit in biology (Hausdorf, 2011). Defining a species also defines what speciation is. Species is one of the most often used biological units; in agricultural and in medicine species must be known and well defined. Species reproductive barriers are semipermeable to gene flow and species can differentiate though there may be inbreeding. Species is a term used to cover all groups of organisms.

The biological concept defines species as ‘groups of actual or potential interbreeding natural populations, which are reproductively isolated from other groups, (Hausdorf, 2011).’In essence a species is considered the biggest gene pool that can occur under natural conditions. Populations connected by gene flow are often hard to classify. While a species concept defines the conditions under which a population should be classified as a species a population are individuals that belong to a specific species and are usually located in an area that is able to be defined.

Populations interact with other populations in their environments and their physical environment; also interacting with those populations of another species. Populations that grow exponentially can reach the maximum sustainable of their population in a certain environment.There are four different forces of evolution; natural selection, mutation, gene flow, and genetic drift. Natural selection has four different components which struggle with each other to change certain traits within populations (University of Michigan, 2010).

Natural selection is subject to inheritance, whereas traits are passed on through heredity, variation such as hair color and eye color or other individual characteristics. An increased rate of population growth means that each population is subject to struggle for a dwindling supply of resources. Finally differential survival and reproduction means that those individual’s more suited to the struggles will pass on more offspring and genes which are able to withstand different conditions. Natural selection depends on traits that are inheritable.

Mutation causes new genetic variations in a certain gene pool. These mutations cause the variation in genetics that allow others evolutionary forces to act such as natural selection, gene flow and genetic drift. Gene flow occurs when individual’s move into and out of certain populations. An example of this would be Americans resettling in other Countries and producing offspring. This affects that population’s gene pool by introducing new genetic variations and affects the population overall and over time.

Random changes are known as genetic drift and occur in several instances. The Bottleneck effect is what occurs when there is a natural disaster or some other outside force which causes a population to get much smaller. Alleles of the survivors may be different than those of the majority of the original population (CK-12, 2012). The Founder effect is when a small number of individuals start a new population and alleles may be different than those of the population they left. These both contribute to changes in genetic expression.

Gene variations with and between populations include sexual characteristics, mutations which can be beneficial or can be harmful though they do not supply what a particular organisms needs and are considered random. Artificial variations can occur in many plants with human interference and gene variations can allow for better adaptations.Isolating mechanisms are properties that a species may carry that will prevent them from interbreeding’s; these mechanisms obviously keep species such as primates and humans from breeding’s or certain plants and animals.

Individual isolating mechanisms define the possibilities of gene combinations. Speciation occurs in many plants, and is an action that produces two individual and separate species. Speciation can occur in geographic isolation when two species which have revolved are reintroduced to each other such as flies. Natural disasters which separate populations and then populations become reintroduced have developed new mating habits and may not mate readily anymore; this is known as speciation.Works CitedCK-12.

"Next: Natural Selection Previous: Hardy-Weinberg Theorem Forces of Evolution." Forces of Evolution. CK-12, 2012. Web. 25 Nov. 2012. www.of-Evolution/?ref=/concept/Forces-of-Evolution/> Hausdorf, Bernhard. "Progress Toward A General Species Concept." Evolution 65.4 (2011): 923-931. Academic Search Premier. Web. 25 Nov. 2012.University of Michigan. "Evolution and Natural Selection." Evolution and Natural Selection. Global Change Univ Mich, 2010. Web. 25 Nov. 2012. www.alchange.umich.edu/globalchange1/current/lectures/selection/selection.html>