The Evolution of Evolution

In the 150 years since the publication of ‘On the Origin of Species’ by Charles Darwin, his theory of evolution by natural selection has been continually modernized and revised and remains, to this day, the subject of some debate.

By this theory, evolution – and therefore speciation – is natural and gradual, and occurs in response to adaptation to one’s surroundings; random genetic mutation is only propagated across generations insofar as the mutation facilitates survival.

Since its inception, its greatest rival has and continues to be creationism (Bridgford 2009). Creationists, who believe in an omnipotent and omnipresent divine entity responsible for all creation, question not only the philosophical validity of the evolutionary theory but indeed the sufficiency of randomness as an explanation for life on Earth (SEP 2003).

Despite the publication of Mendel’s findings preceding Darwin’s by nearly 30 years, only in 1900 did Mendel’s work on heredity resurface and his proposals – of the stabilisation and reversion of species from hybrids to the form of their parents – meet the public eye (Reese 2009).

Shortly thereafter, in the 1910s, the “mutationists” highlighted the pronounced mutations which could emerge abruptly from large-scale reproduction, and the heritability of those traits (The Guardian 2022).

In the 1930s-1940s, the “mathematical population genetic models” of the modern synthesis movement gave credence to Darwin’s theory (Safran and Nosil 2012) with their application of statistical methods in what continues to be known as population genetics and is accepted as mainstream evolutionary biology (The Guardian 2022).

Molecular biologists in the 1960s, who had found very high rates of mutation in molecules in our cells without any input of natural selection, have also queried the basis of the modern synthesis (The Guardian 2022).

Evolution theorists suggest from a systemic standpoint (“evolvability) that larger-scale genetic changes “corresponding to the replacement of large sections of a gene” may assist in speedier adaptation to extreme environmental interference (Bell 2005:1).

In the most controversial recent critique of the modern synthesis, the extended evolutionary thesis proposed by Laland et al (2014) seeks a more inclusive conceptualization of evolution “in which the processes by which organisms grow and develop are recognized as causes of evolution” (Laland et al 2014:161). The group argues that organisms’ development is also impacted by the environment, and vice versa, and calls to account standard evolutionary theory and its “‘gene-centric’ focus” (Laland et al 2014:162).

Natural selection has also been refined by the principle of internal selection, which describes the genetic precision required in each step of an organism’s development in order to render the organism’s continued health and viability (Bonner 2015, citing Whyte 1965). Theoretically, therefore, in addition to natural selection, larger organisms are also more susceptible than smaller organisms to internal selection, given the larger number of steps involved in growth from young to adult (Bonner 2015).

It could therefore be prudent to consider Darwin’s theory of evolution by natural selection not as the sole explanation for the diversification of species, but as the backbone of a broader and more complex web of propositions which continue to be tested and, indeed, evolve.

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References:

• Bell, G. (2005). ‘The evolution of evolution’. Heredity (2005). 94, 1-2. doi:10.1038/sj.hdy.6800608

• Bonner, J.T. (2015). ‘The Evolution of Evolution: Seen Through the Eyes of a Slime Mold’. BioScience. December 2015. Vol. 65 No. 12. 1184-1187. doi:10.1093/biosci/biv154

• Bridgford, N. (2009). ‘Darwin’s Theory of Evolution’. Young Scientists Journal, vol. 2, no. 7, Jan.-Feb. 2009, p. 48. Gale Academic OneFile. Accessed 28 Apr. 2023

• Laland, K., Uller, T., Feldman, M., Sterelny, K., Müller, G.B., Moczek, A., Jablonka, E., and Odling-Smee, J. (2014). ‘Does evolutionary theory need a rethink?’ Nature. Vol. 514, pp 161-164. 9 October 2014.

• Reese, R.A. (2009). ‘Darwin, Mendel, and the evolution of evolution’. August 2009. Significance 6(3):127 - 129 DOI:10.1111/j.1740-9713.2009.00377.x

• Safran, R.J. and Nosil, P. (2012). ‘Speciation: The Origin of New Species’. Nature Education Knowledge 3(10):17.

• SEP. (2003). ‘Creationism’.

• The Guardian. (2022). ‘Do we need a new theory of evolution?’ 28 June 2022.

• Whyte, L.L. (1965). ‘Internal Factors in Evolution’. Braziller.