Evolution is a rather complicated science, with a great amount of rules, laws, and theories in it. Besides, at times the principles of evolution appear not to be quite reasonable when applied to actual examples. Nevertheless, knowledge of the basic principles of evolution allows us to realize the variety of the flora and fauna existing on Earth today. Therefore, in this paper, we shall explore the fundamental aspects of evolution.
Theory of Evolution
As it is known, the theory of evolution which is currently considered the primary explanation of the origin and evolution of species was proposed in 1859. According to Charles Darwin, all living beings have a common ancestor. Throughout their existence, species undergo constant changes affected by their surroundings and acquire various properties. These transformations become possible thanks to variation within species. That is to say, an individual possessing a positive variation will easily manage to adapt to the surrounding conditions and pass on a favorable trait to its offspring.
In this way, throughout several generations the favorable variations will accumulate within the organism resulting in higher adaptation to the environment. Moreover, evolution does not presuppose only the increase in complexity but can be accompanied by loss of traits. This depends on a number of factors including environmental influences. Generally, evolution can be described as a lengthy process which, however, can be accelerated by certain mechanisms, including genetic drift, gene flow, and mutation.
Natural Selection and Adaptation
One of the basic mechanisms through which new traits emerge in the course of evolution is natural selection. Thanks to natural selection, an organism manages to adapt to its environment and survive in adverse conditions. What is more, natural selection impacts variations in a population in a way that only those individuals possessing favorable characteristics will survive while the rest of the population will become extinct.
At the same time, natural selection acts upon various traits of an organism. For example, according to the theory of evolution, the peppered moths of England used to be white-colored as it helped them blend into the background formed by the white bark of trees. However, once there occurred the emergence of industry, leading to increasing levels of pollution, dark-colored moths became much more numerous since they easily camouflaged themselves against the backdrop of black trees.
Genetic Variation and Mutation
An important prerequisite for evolution and any kind of variation within a species is a genetic variation. It appears owing to mutations or alterations of the genes within a species. A mutation may be triggered by a number of factors including errors during DNA replication, exposure to radiation, chemicals, or viruses. As a result, there may be changes in traits, modifications in the organism, or even death in some cases.
That is why, genetic variation is an important precondition for natural selection and its action as otherwise the latter cannot function. Therefore, genetic variation can be observed virtually anywhere. For example, people vary in eye and skin color. Similarly, there exist variations among species of birds inhabiting the Galápagos Islands.
Fossil Record of Evolutionary History
The fossil record is a valuable source providing evidence of the evolutionary history of species. By means of fossils, one can observe how species underwent change throughout million years and discover which species emerged, evolved, or went extinct. For instance, the fossil record shows that organisms existing in the Devonian period possessed the qualities of fishes and lived in water. Meanwhile, the appearance of amphibians allowed organisms to dwell in water as well as on land. Next, mammals replaced reptiles due to certain advantages which the former possessed.
Among others, there were greater intelligence and ability to regulate body temperature. Therefore, the fossil record demonstrates how species managed to adapt to the changing conditions, which is reflected in their evolution.
Evolutionary Mechanisms and Processes
Despite the fact that natural selection is a driving force behind evolution, there are several other important mechanisms affecting the process of evolution. Such mechanisms include genetic drift, gene flow, and mutation. In addition, the processes of speciation and extinction contribute greatly to the diversification of the fauna and flora of Earth. Speciation occurs due to the emergence of a new phenotype or genotype in comparison to other populations of organisms.
That is, due to the development of reproductive isolation, new species form which possess definite advantages over others. Extinction takes place when organisms become unable to compete or reproduce in an ecosystem. In view of the above, it is important to learn about these mechanisms and processes.
Conclusion
To sum up, it is important to understand the basic principles of evolution in order to perceive the diversity of the animal and plant worlds. Knowing evolution makes it possible to trace how species adapted to the changing environment and underwent evolution. Evolution is a rather complicated phenomenon involving numerous mechanisms and processes.
Thus, if you want to expand your knowledge regarding evolution, employ several sources including scientific journals, educational materials, and documentaries.
