Happy Birthday Mr. Darwin!

Today is the 200th anniversary of Charles Darwin's birth.

On this occasion I would like to write a short essay to reflect upon his academic achievement and its wider impact on humanity:

1. Darwin was the first scientist to propose a viable mechanism for biological evolution - natural selection.

His crucial insight stems from two basic observations:

First, that organisms tend to have more offspring than the environment can support.

And second, that every offspring differs slightly from its parents and has the potential to pass down these different traits to the next generation.

Thus, the higher reproductive success of individuals who are able to survive in that particular environment causes the population to evolve adaptive features, in small incremental steps, that are suited to that environment.

Should a population be split into reproductively isolated subpopulations (due to geographical separation, for example), driven by excess reproductive fecundity and differential survival each subpopulation will gradually adapt to their new environments and eventually become so different from each other that they can no longer interbreed.

This explains the origin of species diversity.

2. While Darwin's discovery of natural selection is important, it is the direct implication of biological evolution - that all living organisms are fundamentally related - which has attained a greater impact on biology and wider society.



















Other mechanisms of evolution may have been discovered since then, including mutationism by Thomas Morgan and genetic drift by Motoo Kimura.

But even today, 150 years after the first publication of his On the Origin of Species, Darwin's central idea has withstood the test of time.

Palaeontology, comparative anatomy, biogeography, population genetics, biochemistry and more recently, molecular genetics have all validated the basic truth of Darwin's assertion - that all life on Earth shared one (or a few) common ancestors in the distant past, and that we are all cousin species in an immense Tree of Life.

Common descent is a powerful concept not only because it unifies all of biology as an academic subject, but also because it results in a strikingly different worldview from the anthropocentric views created by old cultural traditions.

With the acceptance of common descent comes the understanding of the interconnected relationships between living organisms, the realization of both the resilience and fragility of life, and the appreciation of the need to have sustainable strategies to allow human civilization to coexist harmoniously with other constituents of Nature.

This worldview underpins a myriad of diverse fields such as biodiversity, conservation biology, infectious disease biology, drug discovery, biotechnology, renewable energy technology and the environmental sciences.

3. The achievement of Darwin stand at least as an equal to that of Isaac Newton or Albert Einstein, not because of any technical ingenuity or mathematical precision, but because of its well articulated ideas supported by meticulous attention to details, its wide ranging impact and the fact that it was published in direct opposition to the cultural climate of its time.

Darwin's life work exemplifies the spirit of scientific inquiry - that a discovery, no matter how bizarre or counterintuitive or socially unacceptable, must be clearly expressed, thoroughly investigated and courageously defended.