How Humans Evolved - Origin of Species - Charles Darwin

Posted on the 01 December 2021 by Sampathkumar Sampath

When on board H.M.S. Beagle, as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species—that mystery of mysteries, as it has been called by one of our greatest philosophers. On my return home, it occurred to me, in 1837, that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it.

‘Humans evolved from monkeys’ – is what we read / understood from school text books .. .. .. it was surprising to see a monkey this morning at my terrace in Triplicane.  It walked in a calm and composed manner, but crows and other birds around were apparently agitated !!

Theory of Evolution explaining how humans evolved -  is the lengthy process of change by which people originated from apelike ancestors!. There are theories citing Scientific evidences that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.

Obviously, erect Homo-sapiens, as we walk, took thousands of years to evolve.  Human evolution, is the process by which human beings developed on Earth from now-extinct primates. Viewed zoologically, we humans are Homo sapiens, a culture-bearing upright-walking species that lives on the ground and very likely first evolved in Africa about 315,000 years ago!  We are now the only living members of what many zoologists refer to as the human tribe, Hominini, but there is abundant fossil evidence to indicate that we were preceded for millions of years by other hominins, such as Ardipithecus, Australopithecus, and other species of Homo, and that our species also lived for a time contemporaneously with at least one other member of our genus, H. neanderthalensis (the Neanderthals). In addition, we and our predecessors have always shared Earth with other apelike primates, from the modern-day gorilla to the long-extinct Dryopithecus. That we and the extinct hominins are somehow related and that we and the apes, both living and extinct, are also somehow related is accepted by anthropologists and biologists everywhere.

Yet the exact nature of our evolutionary relationships has been the subject of debate and investigation since the great British naturalist Charles Darwin published his monumental book – “origin of species’. The opening para is from the book of Charles Darwin, who went on to state – ‘after  five years' work I allowed myself to speculate on the subject, and drew up some short notes ; these I enlarged in 1844 into a sketch of the conclusions, which then seemed to me probable : from that period to the present day I have steadily pursued the same object’.  In his autobiography, Darwin said he had "gained much by my delay in publishing from about 1839, when the theory was clearly conceived, to 1859; and I lost nothing by it". 

Charles Robert Darwin FRS FRGS FLS FZS[2] [1809 – 1882]  was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution.  His proposition that all species of life have descended from common ancestors is now widely accepted and considered a fundamental concept in science. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history,  and he was honoured by burial in Westminster Abbey.

Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species.  By the 1870s, the scientific community and a majority of the educated public had accepted evolution as a fact. However, many favoured competing explanations which gave only a minor role to natural selection, and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.

Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. Studies at the University of Cambridge (Christ's College) encouraged his passion for natural science.  His five-year voyage on HMS Beagle established him as an eminent geologist whose observations and theories supported Charles Lyell's conception of gradual geological change, and publication of his journal of the voyage made him famous as a popular author. Puzzled by the geographical distribution of wildlife and fossils he collected on the voyage, Darwin began detailed investigations, and in 1838 conceived his theory of natural selection.

In mid-July 1837 Darwin started his "B" notebook on Transmutation of Species, and on page 36 wrote "I think" above his first evolutionary tree. In December 1831, he joined the Beagle expedition as a gentleman naturalist and geologist.  In late September 1838, he started reading Thomas Malthus's An Essay on the Principle of Population with its statistical argument that human populations, if unrestrained, breed beyond their means and struggle to survive. Darwin related this to the struggle for existence among wildlife.

On the Origin of Species (or, more completely, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life), published on 24 November 1859, is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. The book was written for non-specialist readers and attracted widespread interest upon its publication. Darwin was already highly regarded as a scientist, so his findings were taken seriously and the evidence he presented generated scientific, philosophical, and religious discussion.  

So a book published this time, 162 years ago, changed the way humans had perceived their own evolution ! interesting !

With regards – S. Sampathkumar
30th Nov. 2021.