Evolution by natural selection is a key element in evolutionary change. Charles Darwin proposed that the process of natural selection occurs due to variation in the ability of organism to survive and reproduce in a particular environment. The proportion of genes in a population depends on mechanisms of natural selection. These are direct selection and diversifying selection, which favor extreme phenotypes, stabilizing selection, which favors intermediate phenotypes, sexual selection and polymorphism and polygenic aspects. Natural selection involves various aspects of dynamic chemistry that allow self-organization. Covalent bonds form and break in a reversible manner so that there is a continuous exchange and reorganization of building blocks. Natural selection is a common phenomenon in changing environments. Organisms in any given environment have different traits largely resulting from genome variations that make the environment either conducive for increasing gene proportions and the number of offspring for certain organisms or a hindrance to the production of offspring.
Analysis of Natural Selection
The derivation of concepts of natural selection occurred at the basic levels of survival of organisms and depended mostly on observation evidence. Evaluation of successful traits relied on observations relating to the longevity of existence of species and populations sizes among different organisms due to diversity in various aspects such as feeding (Darwin 118). The use of data only from basic levels such as disease resistance narrows the scope within which the theory of natural selection evaluates variability of organic life. It lacks satisfactory details about the source of the genetic information that fosters natural selection in diverse environments. Detailing natural selection mechanism such as inheritance and variation, which are key elements of natural selection, will incorporate biochemical processes in the natural selection theory and facilitate extensive analysis to comprehend fully their role in evolutionary change. Research shows that heredity, mutations and sexual recombination are responsible for replenishing and variation of generations. The fact that some organisms survive in environments, which do not favor their natural selection, nullifies some concepts of natural selection. Such organisms should disappear because of selection. Evidence relating to recessive genes and genetic drift illustrates that natural selection is subject to a myriad of factors relating to population genetics.
Darwin’s concept of gradualism does not concur with fossils records that illustrate a sporadic appearance of new forms rather than a gradual and invariant change over time as asserted by Darwin. Analysis of punctuated equilibrium demonstrates that some life forms underwent rapid changes after being in one state for long periods. Since natural selection ensured only the survival of most suitable organisms, the theory does not explain why evolution occurred in the direction of greater complexity (Snooks 27). Evolution did not stop with adaptability to environments. This means that there are forces that drove life to higher levels of organizations. An analysis of bacteria colonies, which a good representation of the life forms used to establish the evolution theory, highlights the flaws in the theory of natural selection. Despite their existence in diverse environments and the presence of many mutants, bacteria never turn into different life forms over generations. Gene selection must occur in a sequence that ensures all components connect in an appropriate and regulated manner for successful natural selection. The complexity of such a phenomenon raises doubts on the applicability of natural selection concerning the attainment of new life forms.
Various chemical and biological analyses demonstrate that natural selection could only have occurred in physical aspects that ensured the survival of organisms, but not due to genetic variation. The lack of explanation for the direction of evolution from simple life forms to complex life forms, and unobserved evolutionary changes in generations of bacteria demonstrates that natural selection occurred in a restricted manner.