Human Intervention and Evolution

Artificial selection involves the interaction of humans in the creation of new species. You are already familiar with genetic engineering, selective breeding and other techniques that manipulate genes. In the genetics unit, you learned about genetically engineered Bt corn, Bt potatoes, and Bt cotton. These genetically engineered plants contain foreign genes that produce proteins which are naturally found in Bacillus thuringiensis (Bt) and act as an insecticide.

Obviously, the Bt plants contain genes that are different from the genes of unmodified plants growing in the same vicinity. The ecological effects of genetically modified plants are still very uncertain. The artificial manipulation of genes may bring environmental benefits or they may have a negative impact on the natural world.

In addition, human activities that alter the natural habitat of species can have a dramatic effect on speciation and extinction. The clearing of natural habitats to build roads, homes and stores can also disturb a natural habitat and set up physical barriers that limit reproduction among populations. The illegal hunting and poaching of elephants has led to a massive decline in the population of elephants in Africa. Elephants are slaughtered for their ivory tusks. http://www.sciencedaily.com/releases/2008/07/080731140219.htm

In a more indirect way, human activities that increase greenhouse gases, coupled with deforestation, have led to global warming. Climate changes greatly affect the behavioural patterns, habitats, and reproductive cycles of organisms. Movement of populations to cooler temperatures may separate individuals which can reduce the reproductive success of the population. In addition, some individuals within a population may adapt to the changing environmental conditions and speciation can occur.

Required Reading Article on GM plants and their potential impact (website). Questions on this article – assessed. Article on climate change (website). Questions on this will be on the test.