Human Intervention and Evolution Artificial selection involves the
- Slides: 6
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.
