Understanding Evolution: The Four Forces Of Evolution Essay Example

The theory of evolution has received much attention by the clergy and the scientific community alike ever since Charles Darwin proposed it. It was proposed in order to explain the source of variation among different organisms as well as explain the possible beginning of life on earth. There have been diverse debates on this theory and the people from all walks of life are divided in perspective due to it. In order to make a clear and strong stand about evolution – whether it is valid or not – it is expedient that several concepts relating to it be understood. All in all, evolution is a complex process that acts upon all organisms including humans. There are basically force forces and mechanisms that acts upon organisms to make them evolve through time.
Before going deeper into the discussion of the four forces of evolution, it is important to first understand three concepts: population, species, and variation. Accordingly, species is defined as organisms that can reproduce by interbreeding. This means that sexual reproduction to produce a fertile offspring is a characteristic of organisms belonging to the same species. Different species cannot inter breed just like a tree and man cannot reproduce sexually. Population, on the other hand, is the number of organisms in a given place at a given time. Population is usually used for a single species, but it can also pertain to the number of species living in a particular area at a particular time. For example, the amount of algae living on a fresh water lake during an algal bloom is an example of population. Another example is the number of species of trees thriving on a particular part of the forest. Note that what characterize species from other species are their genes. Genes change through time, and this change is called variation. In order words, new populations of different species are produced through time due to variation, and this variation is driven by the four forces of evolution and by the isolation mechanism.
Mutation is one of the four forces. This force acts randomly upon organisms. It could happen in a relatively fast rate compared to the other forces. Mutation is brought about by diverse factors. Often, organisms undergo mutation in order to cope with extreme conditions such as excessive exposure to sun’s radiation or even nuclear radiation. Mutation also happens when organisms metabolize substances that could affect the coding of genes. This force acts upon the organism at the cell division stage.
Another one of the four forces is called genetic drift. Genetic drift takes place when certain genes gradually disappear in a given population due to diverse environmental and behavioral factors. The disappearance of a phenotype, like certain color of wings among butterflies, because the butterflies with that color fail to multiply is an example of genetic drift. Another example is when one group of organisms belonging to one species eventually becomes the target of a predator and consumes them to a count that will make their phenotype gradually disappear or drift. Note that one important aspect of genetic drift is that it happens at a single population level of a single species.
Gene flow is another force of evolution. It pertains to the flow of genetic material from one group of organisms to another. This also takes place within populations of a single species. When white Gumamela flower is pollinated by pollens from red Gumamela flower to produce either pink or white with red-spotted offspring, then gene flow has taken place. Gene flow usually results to more phenotypic variation among organisms of the same species. In other words, when two populations of the species with different phenotypes interbreed then gene flow takes place.
The last of the four forces is natural selection. This could happen at very long periods of time. Natural selection is usually but wrongly related to the phrase “survival of the fittest” in the sense that the more aggressive the organism is the more likely its species will survive. What natural selection means is that the genes that allow the organism to survive more in its environment are the ones that are passed down from one generation to the other so that those genes that are not as beneficial to the organism become extinct.
Mutation, genetic drift, gene flow, and natural selection could act upon an organism at the same time; hence, it is rarely concluded that one force dominates the other by simply looking at the variations among organisms. These four forces could act upon organisms through the passing of time and through isolation. Isolation mechanism means that a portion of organisms coming from the same species get isolated or separated from their group into an environment that is different from whence they came from. In order to survive, the four forces acts upon them until their genetic makeup gradually change through time. Sometimes, the change or variation is so extensive that entirely new species develop. When this happens the process of speciation is said to have taken place.