Thursday, 4 February 2016

Are humans driving evolution in animals?

By Prof Adam HartUniversity of Gloucestershire
2 February 2016

Are humans inadvertently driving evolution in animals? Mounting evidence suggests activities such as commercial fishing, angling and hunting, along with the use of pesticides and antibiotics, are leading to dramatic evolutionary changes.

Sitting down to a roast chicken dinner doesn't seem like an obvious opportunity to consider evolution. But it is.

Think about it: those big tasty carrots, that plump, tender chicken and those handsome potatoes all differ markedly from their natural ancestors.

A wild carrot is barely more than a slightly enlarged purple tap-root and red jungle fowl certainly don't have the extravagant cleavages found on modern broiler chickens.

The intentional selection of the qualities we like (such as flavour and size) in domesticated livestock and cultivated crops has led to descendent animals and plants that differ genetically from their ancestors. This change in gene frequency is evolution, and in this case has come about by a process called artificial selection.

Natural selection is basically the same process. The difference is that instead of humans selecting individuals to breed, natural selection pressures such as predation, or the reluctance of females to mate with lower quality males, cause some individuals in a population to prosper and produce offspring while others fare poorly, leaving fewer offspring.

If the trait that caused the parents to prosper has a genetic basis, then the offspring will inherit that trait and likewise prosper, changing the frequency of genes in the population.

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