Contribution of Mendelian Genetics to Darwin’s Theory

Contribution of Mendelian Genetics to Darwin’s Theory


The theory of evolution is generally attributed to Charles Darwin due to his great work and discoveries well documented in his The Origin of Species which was published in 1859. However what many do not know is that this though the birth of the idea of evolution was the initiator of various future discoveries and developments that would be published later. Darwin devoted his entire life to the development of the theory of evolution by means of natural selection but so did other scientists one of them being Gregor Mendel. Mendel main contribution was towards the understanding of genetics and their contribution to the evolution of the human species. The study of the discoveries of the two scientists and how they depended on each other is an important of understanding the theory of evolution taking into consideration there were other scientists works who were also integrated into the final theory.

            Charles Darwin Initial Theory

The theory of evolution is widely accepted among most learners but faces great criticism especially from the church but this was not an issue to Darwin. The theory as indicated on his first book was based on the idea of survival for the fittest by means of natural selection. He argued that the survival of an organism was based on it being fitter therefore having the opportunity to pass its genes over by reproduction while the less fit organisms became extinct. However the process of natural selection was dependent on suitability there had to be a variation in fitness among the various species, existence of heredity and variation on population. The theory argued that the existing species had evolved from simple life forms which evolved to more complex forms as part of their survival skills and the process commenced over 3 billion years ago.

The theory however was not convincing among various scientists more specifically among the biologists and Darwin sort to improve this by writing various papers which were mostly addressed on a range of biological phenomena which covered areas of plants sexual systems and human anatomy and behavior. Darwin’s idea of natural selection specifically faced a lot of skepticism from geneticists such as Hugo de Vries who emphasized on the role of mutations and large and manifold effects (Provine, 1971). The specific cause of controversy was Darwin’s failure to explain why favorable variations are not lost within few generations of breeding with the normal populace. The theory continued to fall out of favor as it became more oblivious that the problems of hereditary had caught up with the theory in a period that lasted up to 1940 known as the ‘Eclipse of Darwinism.’

            Gregor Mendel Work

Better known as the father of Genetics, the Central European monk is well known for his patience and patience is what his work had to have before it was recognized. The 1822 born monk who had a rather short lifespan living for only 62 years first published his work in 1866 but scientists were more obsessed about Charles Darwin speculation rather than his work which was later to be rediscovered in 1900. The initial discovery by Mendel was that certain traits that are present in the offspring, show up without any blending of parent characteristics. This he discovered before setting up the 8 year project of true-bleeding plants more specifically peas. His experiments involved the production of plants which when self-crossed produced similar results followed by years of making thousands of crosses through multiple generation plants.

The results of his long work were however satisfactory, he had come up with a discovery that scientists had struggled to achieve through multiple detailed researches and he identified three main laws. The first law was the law of segregation. The law noted that parental genes were randomly separated to the sex cells so that sex cells contain only one gene of the pair and therefore the offspring inherited only one genetic allele from each parent which meant that each inherited trait is defined by a gene pair. The second law was the law of independent assortment which stated that genes for different traits were sorted separately from one another so that inheritance of one trait is not dependent on the inheritance of another. The third and final law was the law of dominance which stated that an organism with alternate forms of a gene will express the form that is dominant. These laws were the result of the recorded observation of over 10,000 pea plants.

Gregor Mendel Work Application in Charles Darwin Work

The rediscovery of Mendel’s work in 1900 can be said to a very timely discovery because the Charles Darwin theory was under so much criticism which had no answers. One of the major problems of the evolution theory was the hereditary an issue that Darwin had noted and developed the idea of natural selection. Mendel discovery provided a ready solution to this issue with the discovery that alleles of genes are not changed when inherited, they also not blended together, however they remain separate and distinct and separate in the offspring (Sabelli, 2005). Therefore the variation was not lost but persisted through generations maintaining the raw materials for natural selection to take place.

Another issue in Darwin’s theory that Mendel solved was the explanation of how variation could be formed and maintained. This was well explained by the genetic drift which is the arbitrary changes in the incidence of variable alleles of comparable fitness. The variation is therefore explained by the fact that one allele cannot auto-compete the other but random sampling errors can have significant impact on small populations and therefore the high probability that one allele is completely lost during an environmental catastrophe (Llamas, 2011). The work of Mendel did not produce direct solutions to other detailed queries of the evolution theory and it was the work of various population geneticists that identified various details that were applicable to the evolution theory with the development of statistical and dialectic synthesis (Sabelli, 2005).

            Sir Richard Fisher

The London born mathematician who studied mathematics and mathematical physics is one of the key contributors to the synthesis of Mendel’s and Darwin’s work. His first contribution was towards the analysis of the hereditary issue where he noted that genes of childless man could still prosper if the man had enough nephews what is better known as the idea of kin selection (Reeve, 2001). This was a mathematical justification of one of Darwin’s ideas following Mendel’s theory of genetics. Fisher also advanced the theory of sexual selection in his 1915 paper which was known as the Evolution of sexual selection. The epitome of Fisher’s contribution was the formulation of the fundamental theorem of natural selection which indicated contrary to many early geneticists, the Mendelian genetics was fully consistent with the idea of evolution by means of natural selection.

                                           Haldane and Wright

These two individuals collaborated with Fisher in the establishment of the synthesis of the Mendelian and Darwin’s theory but their works received less publicity. Haldane’s most notable contribution was the analysis of the impact of variation in survival or reproduction due to one or two Mendelian genes would affect the population using the example of peppered moth to note the speed of natural selection (Reeve, 2001). Wright’s most notable contribution on the other hand was the analysis of how random genetic drift interacted with selection, migration and mutation. He is also responsible for the introduction of the notion of adaptive landscape whereby natural selection drives a population towards a local maximum but genetic drift pushes the population away from such a peak paving way for natural selection to push it to another peak (Reeve, 2001).


Contrary to what many may think, the existence of the theory of evolution is not solely the work of Charles Darwin but it’s a concerted effort of continued research to deduce various facts about the theory with the major facilitator being Mendelian genetics. Though Mendel’s work was not addressed to the evolution theory and was actually far from that since the Austrian monk was a Christian it has contributed a lot to the theory and it’s actually the reason for the use of the theory up to date. However since the two great individuals never met, credit need to be given to Hugo de Vries who finally understood Mendel’s work and rediscovered it and the endless efforts of Fisher, Haldane and Wright among other scientists  who worked effortless to find the relationship between the two works.



Llamas, E. (2011). Biología Para El Examen de Admisión.  Raleigh:

Reeve, E. C. (2001). Encyclopedia of genetics. London: Fitzroy Dearborn.

Sabelli, H. C., & Kauffman, L. H. (2005). Bios a study of creation. Hackensack, N.J.: World Scientific.

Sant, Joseph (2014). Mendel, Darwin and Evolution. Retrieved from


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