Originof humankind has always been a controversial issue. One of thepopular explanation given to expound about human beings is that he isa product of evolution. Charles Darwin suggested the theory of humanevolution in the famous Darwinian theory of natural selection. Sincethen, several researchers have written on human evolution with eachtrying to criticize or add to already existing knowledge. In hisarticle titled, “Does Natural selection continue to operate inmodern mankind” Dobzhansky examines the validity of this commonassertion in biological, sociological and medical writings. He offersa counter-argument that natural selection has relaxed or at worstdone away with in modern society, especially in advanced societieswhere people have devised means of sustaining themselves despite theharsh or challenging environment.
Thearticle commences by stating that Natural selection is regarded asthe directing agent for human and organic evolution. Since timeimmemorial, people have ensured that they retain the bestcharacteristics through sexual reproduction. However, another causeof evolution is mutant genes which induce a sudden change in thegenome of the organism. Following human evolution, the articleaffirms that organisms with less desired characteristics are oftenlost while those with desirable attributes survive. As this processgoes on over a prolonged period, it results in adaptive modificationor extinction. The author thus seeks to understand whether thecurrent generation is still evolving and if changes of theenvironment such as minimal risks and food security and technologicaladvancements have influenced or done away with evolution and if so,what are the implications for the human society.
Dobzhanskyexamines previous literature and theories on human evolution. Helooks at Darwin’s testimony published in 1838 titled the principleof the population which state that all living species have theability to multiply in geometric progression, and this continue untiltheir source of food is depleted. One this occurs, he acknowledgesthat only those who are stronger, better able to get food and moreintelligent survive. He concludes that natural selection is aboutthose who are genetically fit but not fittest. Additionally, he looksat the concept of reproductive success and how it has played a majorrole in human evolution. He revisits Darwinian Theory and states thatreproduction has been pivotal in human evolution processes because ithas ensured that desirable characters are passed to the subsequentoffsprings (Dobzhansky 593). Here he elaborates on the Mendelianpopulation. He also looks at case studies and biological facts suchas biological and cultural evolution. For instance, to affirm thathuman evolution is still in play, he gives the example of bloodgrouping, Hemoglobin S and malaria.
Accordingto this theory, human evolution is intimately related to the originof life and its subsequent development on earth. Ancient thinkers,for instance, speculated that life on its own developed frominorganic substances after the formation of the earth. According tothem, physio-chemical processes facilitated these creations. Inresponding to whether modern man is still subject to naturalselection, the author states that human evolution processes willcease only if all the genotypes produced surviving children in exactproportion to their frequencies in the population and since thisnever occurs, it is evident that humans will forever continue toevolve. Importantly, the author affirms that the selective forceswhich act to bring about human evolution are natural and notartificial. Dobzhansky claims that fitness and adaptation only applyin relation to the environment. He brands the notion that humanevolution has relaxed as a fallacy (Dobzhansky 596). In his defense,he makes reference to blood grouping and how natural selection andnature has always ensured a balance in that those belonging to 0 aremore susceptible to duodenal ulcers than the rest.
Thearticle also provides a detailed discussion of adaptation and itsrole in natural selection and human evolution. Here, he states thateven though some genes may not be adequately adapted to surviveparticular condition, if they are accorded proper care, they mayeventually have a chance of surviving and passed to the subsequentgenerations. According to Dobzhansky, it is as a result of naturalselection in a civilized condition that enables human genome tooverspecialize. Lastly, the article also talks about human evolutionand civilization. He states that in the modern times, parentalinfluence has affected the success of their children in reproductionand marriages. He affirms that individual and family adjustments arethe modern creation of struggle for existence. He concludes bystating that even though natural selection has spearheaded humanevolution, civilization has also had significant effects becausethere is increasing dependence on cultural heritage, however, man canstill prepare to take over the control to correct any deficiency inevolution.
Inconclusion, it is, therefore, evident that human evolution isprimarily a survival mechanism against environmental challenges thatthreaten man’s existence. Dobzhansky states that it is influencedby genetic factors. On the other hand, irrespective of time, it isevident that human evolution is still taking place. This is shown bybiological indicators such as blood grouping and hemoglobin S andMalaria patients. Evolution and natural selection have always ensuredthat there is a balance to ensure that there is no overdependence.
Dobzhansky,T., & Allen, G. (1956). Does natural selection continue tooperate in modern mankind? AmericanAnthropologist, 58(4),591-604.