Humans have had an influence on evolutionary processes for much longer than you may have thought – we have tamed wolves and wild cats to become the many breeds of domestic dogs and cats that share our homes today and we have selected cattle, sheep, goats and pigs over many generations for food characteristics. Our main food crops such as rice, corn, wheat, as well as many fruit and vegetables, are very different to their wild ancestors.
Artificial selection, or selective breeding, is the process by which humans breed other animals and plants for particular traits; for example, increased size, fast muscle growth or sweeter taste. This can be a deliberate process, like when farmers choose to breed animals or plants with particular characteristics or it can be accidental. In Asia and Africa, over many centuries, bull elephants with particularly large tusks have been targeted as trophies and for their valuable ivory. As a consequence, individuals with large tusks produce fewer offspring and become less frequent in the population. (Read more about elephant evolution here and here).
In more recent times, due to greater understanding of genetic inheritance and modern gene technology, we have been able to identify specific genes that code for particular characteristics and create new breeds of organisms with beneficial traits – drought tolerance, increased productivity or improved storage life, for example.
Play the videos from ABC Splash “Genetic Engineering of Crops”
Some sites that may be useful for your research project: