Charles Darwin developed the theory of evolution by natural selection after traveling around the world on the HMS Beagle and observing organisms on the Galapagos Islands. His theory proposed that organisms evolve over generations through natural selection, where individuals with traits best suited for their environment survive and reproduce, passing on those favorable traits. Examples like the Galapagos finches and tortoises showed how isolated populations on the islands evolved different traits adapted to the local environment over time. The key factors in natural selection are overproduction of offspring, genetic variation between individuals, competition for limited resources, and the selection of individuals with traits better suited for the environment to reproduce and pass on their genes.

1. Changes over Time:
Theory of Evolution of
Living Things
Part I
All words/terms in
PURPLE should be
copied into your
Vocabulary Packet

2. What is Evolution?
Any change in the heritable traits within a
population over generations

3. What are “Species”?
Organisms that can successfully
reproduce with each other and their
offspring can also reproduce

4. Theories of Evolutionhttp://www.youtube.com/watch?v=pPghdBIGW9g&list=PLF33D061B83551193
Charles Darwin, 1859
Traveled around the world on
HMS Beagle
Made many stops in Galapagos Islands in
South America

5. Darwin’s Theory of Evolution
Evolution by: Natural Selection
Also known as “Survival of the Fittest”
Definition: organism with the best
traits suited for their environment
survive and reproduce

6. Galapagos
Tortoises

7. Why are these iguanas
so different from each
other?
Iguana from Mainland
South America
Iguana from
Galapagos Islands

8. Galapagos Finches
Which species would you expect to eat seeds?
Which species would you expect to eat insects?

9. Adaptation
Characteristic making one more
suitable for their environment
Example:
Pointy beak for capturing insects
Broad, strong beak for eating hard seeds

10. Copy the information on the next
several slides onto the graphic
organizer.

11. Factors of Natural Selection
1) Overproduction: more organisms
are produced than can actually
survive

12. Factors of Natural Selection,
continued
2) Variation: any difference between
individuals of the same species
Think about your own species, Homo sapiens
Why is variation important?
Can bring about new species after
evolving many generations
http://www.youtube.com/watch?
v=svHQ4BQY__o

14. Factors of Natural Selection,
continued
3) Competition:
Struggle
among
organisms for
resources (like
food, water,
shelter)

15. Factors of Natural Selection,
continued
4) Selection:
Offspring with the better traits have
higher reproduction rate, and over
time make up more of the population
(Population: group of species living in
the same area)