Darwin proposed natural selection as the mechanism of evolution Ch. 14.3 Darwin’s Theory of Natural Selection • A POPULATION group of individuals of the same species living in the same area at the same time • If one species of animal lives on an island, that POPULATION is different from a separate species living on the same island Observations Lead to a Question • 13 species of finches unique to the Galapagos Islands. – Closely resemble a species near S. American’s mainland • What is the hypothesis behind this? More Observations Lead to an Idea • Based his theory on 2 key sets of observations – Only small % of offspring will survive each generation – Population VARIATION differences among members of the SAME species • Using these observations led to NATURAL SELECTION Artificial Selection • ARTIFICIAL SELECTION selective breeding of domesticated plants and animals to produce offspring with genetic traits that human value – When do you think this is used? What type of industry? Pesticides – Natural Selection in Action • Some insects have evolved in order to become resistant to certain pesticides – Initial results would kill the bugs, what would happen as the generations continue? Concept Check • In Darwin's view, what conditions lead to a struggle for existence among individuals in a population? • What is the goal of artificial selection? • Why does a specific pesticide become less effective over time?