Evolution Theories: Natural Selection, Skin, Intellect

Evolution by natural selection

Evolution by natural selection is a process by which genetic traits are passed on to successive generations, to make future species become better adapted to their environments. Survival for the fittest is the name given to this process since the driving force here is natural selection (Pontarotti, 2011). This process occurs naturally where due to their genetic makeup and the ability of mutation occurrence, organisms can adapt and survive in their environments, and transfer their genetic traits to forthcoming generations (Emerson, 2010). In the survival for the fittest concept, organisms that do not develop characteristics to adapt to the environment, are automatically gradually eliminated and only those with favorable characteristics survive. The ones with unfavorable characteristics either migrate to friendly areas or get eliminated completely from the environment. In other words, the level of fitness and heritability variation determine chances of survival (Emerson, 2010).

Within the last 200 years, evolution has led to the emergence of antibiotic-resistant bacteria (Swallow, 2003). Structural changes in the body systems of the bacteria have made some bacteria that were once resistant to antibiotics, no longer resistant to them, and these changes have been pure because of the process of evolution (Swallow, 2003). For example, benzylpenicillin was previously used to treat diseases and illnesses caused by Neisseria gonorrhoeae and Staphylococcus aureus in the past but, nowadays, these bacteria and others have become resistant to this antibiotic, and the drug is no longer effective in treating diseases caused by these bacteria (Ohta & Nishikimi, 2010).

The emergence of insecticide-resistant insects is another credible example of evolution within the last 200 years. Previously, many insects were eliminated by common insecticides but due to evolution, some insects have become resistant to these insecticides hence clearly indicating that the insects have undergone evolution (Emerson, 2010). For example, a study carried out in New York showed that bedbugs in the state have become resistant to pyrethroid toxins, which were earlier effectively used to eliminate the bedbugs. The study clearly indicated that the evolution has affected sodium channels in the outer membrane’s neurons, where the production of electrical nerve impulses takes place, and this has made it very difficult for the pyrethroid toxins to kill the bedbugs. Basically, evolution affects or alters the body structure or system of an insect and this makes it difficult for insecticides, which used to kill the insects to work properly, hence making them less relevant in eliminating the insects. The evolutionary changes have taken place so as to make the bacteria and insects survive in antibiotic and insecticide’s prone environments respectively. These two examples provide a clear analysis of a recent non-human evolution and if the evolution continues, current insecticides and antibiotics may also become less relevant in the future (Ohta and Nishikimi, 2010).

Human skin color evolution

A range of skin colors has evolved over the last 10,000 years. This is believed to have been a result of either the loss of human body hair or migration out of Africa. The changes that these conditions have inflicted on the skin are what have determined the darkening or whitening of human skin (Jablonski, 2004). The distribution of human beings is in a way that people who are dark-skinned are found in high ultraviolet (UV) radiation regions. Lighter-skinned people are mostly found in low UV radiation areas (Chaplin and Jablonski, 2000).

Discoveries have proofed that most mammals and humans long ago had hairy bodies. This protected them from the sun just like other apes. With time, humans lost hair in order to cool in the hot African savannah environment. Adaptations to protect sweat glands and the skin from cancerous and folate destruction have led to the development of dark skin pigments, which have evolved through the natural selection process (Jablonski, 2004). During the migration of human ancestors from Africa to other areas far from the equator, differences in skin colors started emerging. This was due to genetic mutation in order to enable absorption of more sunlight in low UV regions. The human body needs vitamin D, which can only be attained through the skin absorption of UV radiation. There are various skin colors nowadays in humans. This is as a result of a selective tension between the need for skin protection from the sun, and for vitamin D synthesis to prevent vitamin D deficiency (Chaplin and Jablonski, 2000).

Intelligent Design evolution theory is not a scientific theory

Respected scientists in this field support the contemporary theory of evolution and argue that the theory provides well-tested and robust explanations regarding life history. This is a scientific theory that is supported by extensive research and various experiments and observations in the natural world. The theory explains that intelligent causes played a critical role in the formation of the universe and life (Calvert and Harris, 2003). The ID theory proposes that living organisms are too complex to have resulted from natural selection and therefore, the designs must have been as a result of the application of supernatural intelligence. The theory avoids aligning with the bible and fails to name any specific deity as the source of the supernatural intelligence and influence (Peters and Lock, 2010).

The creationist theory on intelligent designs conflicts directly with the vast scientific sources of evidence that current species were created over a long period of time up to 4 billion years. The theory only suggests that current species were only created in 4004 B.C. ID is not considered to be science by the scientific community but just as a tenet or religion (Calvert and Harris, 2003). ID only bases its ideas on observations of the natural world but fails to test them in the natural world in order to explain their mechanism. Scientific theories are limited to using evidence from the natural world to explain a concept or phenomenon. It is not considered scientific if a theory bases its argument on spiritual beliefs, things which cannot be put to test or measured. This is considered a belief in a higher being hence personal and cannot be scientific (Calvert and Harris, 2003).

The scientific theory of evolution

Scientific evolution is a well-tested description of the history of the earth and life. It looks into how earth’s present organisms rose from common ancestors as far as 4 billion years ago to single-celled organisms. The scientific theory of evolution best tries to explain the relationship between different living organisms, keenly looking into the differences in their characteristics and similarities. This involves studies of changes and sequences in rock fossils and the molecular evidence as provided by modern genetics, to trace how ancient organisms have transformed to give rise to many changes in populations over millions of years until now (Sebel, 2004). Inheritable changes are the basis of the evolution theory and it postulates that traits move systematically along generations so long as there exists heritability ability. The transfer of traits from one generation to another makes the future species easily adapt to their environments, after which they also pass the traits to the next generations. These changes are determined by forces such as natural selection in which living organisms with specific genetic traits that are favorable to survive in an environment are passed on to the next generation. This survival depends on the fitness of the organisms to survive in that specific environment (Pontarotti, 2011)

Evolution and Religion

The theory of evolution over the years has had many controversies, which still prevail. The main controversy lies between the scientific perception of interpreting evolution and religion. There are many aspects to which evolution contradicts religious beliefs. Evolution refers to life from the existing point of view while religion views life from the biblical aspect of creation. The evolution theory claims that it is possible to determine ancestry through the following links while the bible argues that human beings were created by God (Calvert and Harris, 2003). Though merging of the two approaches had been tried by scholars by arguing that the only explanation given by evolution is the process of how God created life, there is a mismatch with the bible’s explanation. The macroevolution concept is the only contention between the two. This is because of the visible evidence in nature, though macroevolution mostly concentrates only on the species level. This hardly talks in line with the bible in which God was personally involved in the creation process (AIA, 2008). According to Brooks (2008), many theologians see evolution as a continuation of creation. They refer to creation as not just an act that happened far away in the past, but also as an ongoing process, and evolution is considered as one aspect of creation (O’Leary, 2004).

References

AIA. (2008). Evolution override. Web.

Brooks, A. (2008). Reconciling science and religion. Web.

Calvert, H. J., & Harris, S.W. (2003). Intelligent design. Web.

Chaplin, G., & Jablonski, N. G. (2000). The evolution of human skin coloration. Journal of Human Evolution, 39, 57-106.

Emerson, R.W. (2010). Evolution and natural selection. Web.

Jablonski, N. G. (2004). The evolution of human skin and skin color. Annual Review of Anthropology, 33 (1), 585-623.

O’Leary, D. (2004). By design or by chance? Ontario: Castle Quay.

Ohta, Y., & Nishikimi, M. (2010). Random nucleotide substitutions in primate nonfunctional gene for L-gulano-gamma-lactone oxidiase, the missing enzyme in L-ascorbind acid biosynthesis. Journal of Biochimica et Biophysica Acta, 1472, 408-411.

Peters, R.C., & Lock, A. (2010). Handbook of human symbolic evolution. London: John Wiley & Sons, Inc.

Pontarotti, P. (2011). Evolutionary biology: Concepts, molecular and morphological evolution. New York: Springer.

Sebel, R. H. (2004). Barron’s MCAT: Medical college admission test. New York: Cengage.

Swallow, D. M. (2003). Genetics of lactase persistence and lactose intolerance. Annual Review Genetics, 37, 197-219.

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