Humans Made Pigs and Prey Evolve

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Humans made pigs and prey evolve, according to articles in EurekAlert 12 and 15 Jan 2009 and New Scientist, 16 Jan 2009. A team of researchers led by evolutionary ecologist Chris Darimont from University of California, Santa Cruz have analysed changes in 29 species that are commercially harvested, including fish, shellfish, bighorn sheep, caribou, and two plant species, Himalayan snow lotus and American ginseng, and compared the rate of observable changes in characteristics such as size and age at reproduction with wild populations. They found “harvested populations are on average 20% smaller in body size than previous generations, and their age of first reproduction is on average 25% earlier”. The changes are not due to mutations of the genes in the species but rather are a response to the changing ecology brought about by human predation, e.g. smaller fish can escape gill nets and then pass on the genes for smaller size, or reproduction occurring earlier because smaller populations of fish are now competing for the same food source and are therefore better nourished.

Dirmont commented: "The pace of changes we're seeing supersedes by a long shot what we've observed in natural systems, and even in systems that have been rapidly modified by humans in other ways. As predators, humans are a dominant evolutionary force."

Meanwhile a team of researchers led by Leif Andersson of Uppsala University have studied variations in a gene for coat colour in wild boars and domestic pigs to see why domestic pigs come in numerous different colours but wild pigs are fairly uniform in colour. They found numerous variations of a gene named MC1R, which codes for coat colouring protein, in the wild and domestic animals, but the variations had different effects. Gene varieties in wild boars did not result in change in the coat colour, but the varieties found in domestic pigs did change the coat colour. The researchers concluded that the different coat colours in domestic pigs were the result of deliberate selection by humans, and the uniformity of coat colour in wild pigs was the result of mutation that resulted in changing the coat colour being eliminated from the population in order to maintain the camouflage effect of the colour. "Every time a gene mutation arose in the wild causing coat colour to change, it was eliminated immediately," Greger Larson of Durham University, UK, who also took part in the study, explained to New Scientist, "So if a black piglet showed up, that was the one picked off by a predator."

The EurekAlert article concludes with a comment about how this study is evidence for evolution: “The present study also sheds light on the process of molecular evolution. Charles Darwin was the first to recognize the importance of studying domestic animals as a model of evolution. An argument that has been raised against Darwin's theory is that it is impossible to create complicated structures like an eye, based on the underlying random process of mutation.” They then quote Leif Erickson: "This study shows how quickly a protein can change under strong selection and how humans have ‘created’ black-spotted pigs by selecting several consecutive mutations that have occurred by a random process".

Editorial Comment: These studies show that mutations and selection are real processes and can cause change in living organisms, but the changes referred to in this research are not evolution. The small, coloured or early reproducing animals are still the same species. The elimination of large or coloured animals from a population does nothing to change it into anything else. The leap in logic to humans selecting for a mutation-caused variation in colour in pigs, providing evidence for the same processes evolving the structures needed to make an eye, is also false. Humans did not create black spotted pigs. They just kept them alive when they arrived.

Neither did mutation make the protein coded by the MC1R gene. They just changed an already existing gene and protein in small ways. The fact that some of the mutations were preserved by human selection does not explain how the original gene and protein came into existence.

These modern scientists are using the same deceptive logic that Darwin used in his day. Darwin described many examples of how selection by humans of domestic animals resulted in variation and change within species. He then bluffed people into believing that such changes within a kind could over vast ages change one kind of living creature into a totally different kind. 150 years later people are still being bluffed. (Ref. artificial selection, domestication, natural selection)

Evidence News 4 February 2009

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