Darwin's masterpiece revisited

Agrociencia Uruguay, 2023

Israel Journal of Ecology and Evolution, 2009

The publication of Darwin's On The Origin of Species by Means of Natural Selection in 1859 shook the biological world not only because Darwin argued effectively for evolution, an idea that many others had advocated before, but also because Darwin proposed a compelling mechanism for adaptive evolution called natural selection. Darwin argued that organisms vary in many traits. If these traits influence the ability of an individual to survive and reproduce in an environment, and if the variation can be transmitted to subsequent generations, then those traits that increase the chances for survival and reproduction in the context of the environment should increase in frequency in the population, leading to adaptive evolutionary change. Concerning heritable variation, Darwin initially accepted the theory of blending inheritance, in which traits represent a mixture or average of the traits of the two parents. The underlying mechanism of blending inheritance, or any mode of inheritance, was unknown to Darwin, but he did argue that "Some have even imagined that natural selection induces variability, whereas it implies only the preservation of such variations as arise and are beneficial to the being under its conditions of life" (Darwin, 1872). Hence, Darwin initially made a strict separation between the creation of heritable variation that was random with respect to the conditions of life and the subsequent operation of natural selection upon this variation. Indeed, this was the principle distinction between Darwin's theory of natural selection and Lamarck's earlier proposals for adaptive evolution through acquired characteristics. Darwin's ideas were attacked by many, and Darwin addressed these criticisms in subsequent editions of On The Origin of Species after 1859. Darwin was particularly disturbed by the attack of the Scottish engineer Fleeming Jenkin who pointed out in 1867 that when heritable variation arose in the environmentally independent fashion envisioned by Darwin, it would quickly be homogenized back to the population average under blending inheritance (half of the variation would be lost every generation). Natural selection would have to be extremely strong to overcome this strong tendency towards homogenization. Darwin admitted (Darwin, 1872) that "until reading an able and valuable article in the North British Review (1867), I did not appreciate how rarely single variations, whether slight or strongly-marked, could be perpetuated." To solve this problem, Darwin invoked in Chapter IV of his 6th edition of The Origin the idea of directed variation in addition to natural selection: "There can also be little doubt that the tendency to vary in the same manner has often been so strong that all the individuals of the same species have been similarly modified without the aid of any form of

2000

Darwin’s ideas on variation, heredity, and development differ significantly from twentieth-century views. First, Darwin held that environmental changes, acting either on the reproductive organs or the body, were necessary to generate variation. Second, heredity was a developmental, not a transmissional, process; variation was a change in the developmental process of change.An analysis of Darwin’s elaboration and modification of these two positions from his early notebooks (1836–1844) to the last edition of the Variation of Animals and Plants Under Domestication(1875) complements previous Darwin scholarship on these issues. Included in this analysis is a description of the way Darwin employed the distinction between transmission and development, as well as the conceptual relationship he saw between heredity and variation. This paper is part of a larger project comparing commitments regarding variation during the latter half of the nineteenth century.

2019

Evolution, 2011

Nature Precedings

February 12th, 2009 was Charles Darwin's 200th birthday, and November 2009 represents the 150th anniversary of the publication of his transformative book, The Origin of Species (Darwin 1859). It seems a good time to look back and assess Darwin's legacy within the perspective of current knowledge of genetics, cytogenetics, and molecular biology in general. Although a comprehensive understanding of evolution would no doubt have emerged eventually, it is difficult to imagine how anyone could have matched Darwin's prodigious and sustained efforts, as well as his talent for explaining things in simple terms.

American Journal of Physical Anthropology, 1992

Written for my AP Biology final, I was asked to research any topic in biology and write about. I've always been fascinated with evolution and the process that Darwin went through while developing his theory. This paper discusses the timeline of Darwin's discoveries and his publications, the immediate effects of his theory on science, and the current developments in science based on the knowledge of evolution.

2009

He had travelled most of the major coastlines of the globe. For five years at a stretch. He had surveyed the flora and fauna of the islands, coastal waterfronts, and the nearby peninsula. He had also studied the marine reefs, landmass, rocks, soil and climatic characteristics. He had collected crates of specimens from the entire area under survey. And in the process there were two metamorphoses in his life – one academic and the other ideological. He had started the journey across the Atlantic in 1831 with a view to making a secure career in geology; but when he came back to the shores of England in 1836 he had already embarked on the path to become a biologist – and a foremost biologist of the nineteenth century. Second, he had boarded the ship HMS Beagle as a devout Christian; and five years later, when he set foot on the banks of the Thames, he had turned into an agnostic. Yes, you have rightly guessed that we are talking of Charles Robert Darwin. Since last year we are observing...