In 1859 Charles Darwin published, ‘On the Origin of Species: By Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. But is Darwin’s theory relevant today?
While Darwinian evolution based on random mutations provides a compelling framework for understanding the gradual development of species over time (speciation), the fossil evidence for the ‘Cambrian explosion’ of lifeforms 560 million years ago presents challenges to this view.
The relatively sudden appearance and rapid emergence of complex body plans, the lack of transitional forms, and the presence of advanced traits suggest that additional mechanisms or biological processes may have played a role in shaping speciation and the diversity of life on earth.
An alternative view to classic Darwinian evolution has emerged since the discovery of the ‘epigenome’. The epigenome can influence phenotypic plasticity, which is the ability of an organism to change its physical characteristics (phenotype) in response to environmental cues (Rando and Vestrepen, 2006).
Epigenetic modifications can regulate the expression of genes involved in developmental processes, allowing organisms to adjust their traits to better suit their environment. This plasticity enables organisms to survive and reproduce in diverse conditions without requiring genetic mutations, facilitating more rapid adaptation of life forms to their environment.
Although most mainstream evolutionary biologists continue to adhere to ‘Darwinian’ evolution based on a mechanism of random mutations as the primary engine of evolution, the chemical interaction between environment and epigenome may play a more important role in the adaptation of life forms to their environment than the theory of random mutations, the vast majority of which are infrequent and usually not positive or ‘useful’ mutations.
Therefore, the novel concept of epigenetic evolution provides a more plausible alternative evolutionary mechanism to explain the rapid diversification of life forms during the Cambrian period over tens of millions of years as opposed to the protracted process of survival of the fittest via selection of species based on random mutations, which from a probabilitistic perspective could not have ocurred with a time frame consistent with the age of the habitable earth.
Our understanding of the interplay between genetic and epigenetic mechanisms is essential for comprehending the intricate processes that contribute to the remarkable diversity of life on Earth.
In summary, through phenotypic plasticity, gene regulation, transgenerational inheritance, environmental sensing, and epigenetic variation, the epigenome not only facilitates adaptation but these acquired genetic characteristics are inheritable, thus allowing species to thrive in diverse ecological niches.
However, further research and exploration are needed to fully understand the complexities of the Cambrian explosion and its implications for alternate evolutionary theory.
1-https://www.cell.com/fulltext/S0092-8674(07)00121-3
