Daily Archives: 23 December 2013

December 23, 1924 (a Tuesday)

First fossil skull of Australopithecus.

On this date, Raymond Dart completed his work removing the first fossil skull of Australopithecus from its matrix of rock. Being one of the “missing links” in man’s evolution, Dart had taken exquisite care during 73 days to separate skull and stone, at work in his laboratory in Johannesburg, South Africa.

Dart with his students made the find in the Taung limestone works in the Harts Valley of Bechuanaland. When an endocranial cast was found, at first it seemed to be just another primate skull. Then, Dart noticed how amazingly close to human it looked. Dart had discovered the Taung child, who was only three years old at the time of death. He named it Australopithecus africanus. (Australis means “south” and pithecus means “ape”).

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December 23, 1810 (a Sunday)

Edward Blyth

On this date, the English zoologist and chemist Edward Blyth was born in London. Although he was considered one of the leading zoologists in India, and a prominent figure overall in his field, he is best known for his early recognition of some of the principles of natural selection. In three articles on variation published in The Magazine of Natural History between 1835 and 1837, he discussed the effects of artificial selection and described the process in nature (later called natural selection) as restoring organisms in the wild to their archetype (rather than forming new species). Also, he never actually used the term “natural selection”.

Blyth believed that natural selection only preserves a constant and unchangeable type or essence of created form, by eliminating extreme variations or unfit individuals that deviate too far from this essence. Ernst Meyer wrote that:

Blyth’s theory was clearly one of elimination rather than selection. His principal concern is the maintenance of the perfection of the type. Blyth’s thinking is decidedly that of a natural theologian…

In fact, according to Stephen Jay Gould, natural selection was a common idea (but not a term) among biologists of the time, as part of the argument for created permanency of species. It was seen as eliminating the unfit, while some other cause created well fitted species. Blyth considered that species had “invariable distinctions” establishing their integrity, and therefore could not accept the formation of new species because if it occurred, “we should seek in vain for those constant and invariable distinctions which are found to obtain”. Blyth did not see the ramifications of the principle (nor did anyone else), and did little to develop his thoughts any further.

In contrast, Darwin introduced the idea that natural selection was creative in giving direction to a process of evolutionary change in which small hereditary changes accumulate. He did not read Blyth until after formulating his own theory.

Blyth remained a valued correspondent of Darwin’s after his formal publication of evolution by natural selection, and remained a strong friend of Darwin. Blyth was one of the first to embrace Darwinism, and was a vocal supporter for the remainder of his years.

Interestingly, Blyth’s writings had a major influence on Charles Darwin. There can be no doubt of Darwin’s regard for Edward Blyth – in the first chapter of The Origin of Species he wrote:

…Mr Blyth, whose opinion, from his large and varied stores of knowledge, I should value more than that of almost any one…

References:

    • de Beer, Gavin. Charles Darwin: Evolution by Natural Selection. (London: Thomas Nelson & Sons, 1963) p. 102.
    • Gould, Stephen Jay. The Structure of Evolutionary Theory. (Cambridge, Massachusetts: Harvard University Press, 2002) pp. 137–141.
    • Mayr, Ernst. The Growth of Biological Thought. (Cambridge, Massachusetts: Harvard University Press, 1984) p. 489.