Evolution by Natural Selection
A Darwinian View of Life
Essential Question(s)
1. How do organisms evolve?
History of Evolutionary Theory
What is Evolution?
Charles Darwin
Fossil Record
Biogeography
Succession of Types
“This wonderful
Glyptodon (unique to S. America)
Armadillo (most species in S America)
relationship in the same
continent between the dead
and the living will… throw
more light on the appearance of
organic beings on our earth,
and their disappearance from
it, than any other class
Giant Ground Sloth (extinct)
of facts.”
Modern Sloth
Galapagos Islands
Darwin’s Finches
Adaptive Radiation
Turn and Talk 1
Natural Selection
“Variation is a feature of natural populations and
every population produces more progeny than its
environment can manage. The consequences of this
overproduction is that those individuals with the best
genetic fitness for the environment will produce
offspring that can more successfully compete in that
environment. Thus the subsequent generation will
have a higher representation of these offspring and
the population will have evolved.”
-Charles Darwin, On the Origin of Species
1. Variation
2. Inheritance of Traits
3. Overproduction of Offspring
4. “The Struggle” …for existence
…for existence
5. Differential Survival
…for
6. Differential
existence Reproduction
Populations evolve, not individuals!
Descent with Modification
Turn and Talk 2