Download Darwin proposed natural selection as the mechanism of evolution

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?