Extinction and Extermination

In the summer of 1833 Charles Darwin was exploring the South American landscape when he came across the army of the Argentine general Juan Manuel de Rosas. Though Darwin admired the commander's horsemanship and leadership, the general was engaged in the bloody extermination of native people from southern Argentina. As Darwin recounted in the Voyage of the Beagle;

General Rosas's plan is to kill all stragglers, and having driven the remainder to a common point, in the summer, with the assistance of the Chilenos, to attack them in a body. This operation is to be repeated for three successive years. I imagine the summer is chosen as the time for the main attack, because the plains are then without water, and the Indians can only travel in particular directions. The escape of the Indians to the south of the Rio Negro, where in such a vast unknown country they would be safe, is prevented by a treaty with the Tehuelches to this effect;--that Rosas pays them so much to slaughter every Indian who passes to the south of the river, but if they fail in so doing, they themselves are to be exterminated. The war is waged chiefly against the Indians near the Cordillera; for many of the tribes on this eastern side are fighting with Rosas. The general, however, like Lord Chesterfield, thinking that his friends may in a future day become his enemies, always places them in the front ranks, so that their numbers may be thinned.

This was genocide, a brutal campaign of extermination against native people, and this was far from an isolated event. From South America to Australia to Africa, it seemed that western powers were either trying to convert, enslave, or wipe out "savage" races of people. While he could understand the benefits the western powers were after (like arable land) Darwin was horrified by this trend. He was raised in a family with a strong abolitionist tradition and strongly believed that all races were members of just one species (not many, as some of his contemporaries affirmed). Still, there seemed little that could be done. While he certainly did not advocate such horrors the idea that some races or tribes might be driven to extinction by colonial powers seemed inevitable.

Darwin's background and personal views on such atrocities are more fully detailed in Adrian Desmond and James Moore's recently-published tome Darwin's Sacred Cause, which I hauled along with me during my trip to Delaware. I have yet to finish it, so perhaps Desmond and Moore state what I am about to consider in the latter half of the book, but as I was reading it I could not help but wonder if Darwin's views of extinction were influenced by the attempts of western powers to wipe out or control native people in far off countries.

When we discuss extinction today we often speak in terms of mass extinctions and catastrophic ecological events, like the aftermath of an asteroid striking the earth or rapid global climate change. Darwin, however, was writing at a time when such catastrophic events had been all but buried by uniformitarianism, or the gradual operation of more ordinary phenomena still observable today. (See S.J. Gould's Time's Arrow, Time's Cycle for more on this.) To suggest that massive floods or ice ages wiped out scores of organisms all at once required special pleading.

For Darwin, extinction went hand-in-hand with evolution by natural selection. It was not so much changes in ecology that made creatures become extinct but the struggle for existence between a parent species and daughter species. Given that daughter species would be "improved" versions of their parent species, and both would have similar ecological needs, it seemed probable that they would come into a competition that the daughter species would be more likely to win. As Darwin wrote in On the Origin of Species;

The theory of natural selection is grounded on the belief that each new variety, and ultimately each new species, is produced and maintained by having some advantage over those with which it comes into competition; and the consequent extinction of less-favoured forms almost inevitably follows. ... Thus the appearance of new forms and the disappearance of old forms, both natural and artificial, are bound together. ...

The competition will generally be most severe ... between the forms which are most like each other in all respects.

Hence the improved and modified descendants of a species will generally cause the extermination of the parent-species; and if many new forms have been developed from any one species, the nearest allies of that species, i.e. the species of the same genus, will be the most liable to extermination. Thus, as I believe, a number of new species descended from one species, that is a new genus, comes to supplant an old genus, belonging to the same family.

Invasive species could likewise wipe out similar, but evolutionarily unrelated, species. In fact, Darwin thought that the immigration of a group of organisms into a new part of the world could spur even more rapid extinction than the slower process of evolution and extinction that took place between parent and daughter species. It all came down to competition.

Now, while Darwin was adamant that people of all races belonged to just one species that shared an ancient common ancestry with apes, it is possible that the horrors of Rosas' campaign, the pernicious hold of slavery, and other atrocities influenced Darwin's view of extinction. He saw first hand what happened when more "civilized" people competed with native people for land and resources. It was not competition between a parent and daughter species, but such battles did parallel the competition and replacement of "unadvanced" populations by "improved" types (the "improvement" primarily being cultural, and thus potentially accessible to the people being wiped out in other circumstances).

Keep in mind that this is simply a historical hypothesis. Correlation does not prove causation, and Darwin assiduously collected examples from ecology and natural history to support his concept of extinction. Still, as Desmond and Moore illustrate in Darwin's Sacred Cause, Darwin often compared what he observed elsewhere in nature to aspects of our own species, from our biological origins to culture. Perhaps the association I have presented here does carry some weight, but in order to adequately support or refute my statements I will have to delve into Darwin's many transmutation notebooks.