Evolution and Environmental Science

Natural selection Natural variability in the population Variability in resistance to pesticides Some individuals highly susceptible Some individuals highly resistant Characteristics of individuals are heritable (passed on from generation to generation) Pesticide application to crop kills the susceptible individuals but not the resistant ones

Resistant Individuals

The Result By natural selection the population has evolved resistance to the pesticide Spend millions to develop a new pesticide Repeat the process A continuing evolutionary arms race with pest organisms

Can this pattern be broken? Evolved resistance Develop new pesticide Can this pattern be broken?

Genetic Engineering and the Environment Cloning A bad idea for industrial agriculture No variability in the flock on which natural selection can work All susceptible to the same pests, diseases or predators What are the reasons for cloning? Organ banks

Genetic Engineering of Crops Insertion of beneficial genes Bacillus thuriengensis or Bt Insert the Bt gene into corn All cells of the corn plant produce the Bt toxin killing pests that eat the corn That is good…… But…….

Evolved resistance to Bt Develop new gene

Transfer of pollen to non target species

Transfer of pollen to non target species

Evolotion of a superweed Transfer of pollen to non target species

Other transgenic organisms