1. Darwin’s Theory of Evolution
Chapter 15
Darwin’s Theory of Evolution

2. Charles Darwin Charles Darwin- the father of evolution (1809-1882).
Darwin traveled around the world for 5 years on the HMS Beagle. He collected data and made observations of many unique organisms.

3. Darwin’s Journey

4. Giant Tortoises of the Galápagos Islands
Section 15-1
Pinta
Tower
Pinta Island Intermediate shell
Marchena
James
Fernandina
Santa Cruz
Isabela
Santa Fe
Hood Island
Saddle-backed shell
Floreana
Hood
Isabela Island
Dome-shaped shell

5. Hutton and Lyell
Proposed that the earth rocks moved up beneath the earth.
This process is extremely slow.
The conclusion was that earth is extremely old.
Lyell said that the only way to explain what occurred in the past is to use processes that occur today.

6. Movement of Earth’s Crust
Section 15-2
Movement of Earth’s Crust
Sea level
Sea level
Sedimentary rocks form in horizontal layers.
When part of Earth’s crust is compressed, a bend in a rock forms, tilting the rock layers.
As the surface erodes due to water, wind, waves, or glaciers, the older rock surface is exposed.
New sediment is then deposited above the exposed older rock surface.

7. Lamarck Recognize living things change.
Proposed his own evolutionary hypothesis.
1. Tendency towards perfect.
2. Use and disuse.
3. Inheritance of acquired traits.

8. Figure 15–7 Lamarck’s Theory of Evolution
Section 15-2

9. Origin of Species Was published 25 years after his famous voyage.
He was prompted by Alfred Wallace’s work.

10. Darwin’s Conclusions
Artificial selection helped spur the creation of new species.
Example: breeding of fast horses.

11. Darwin’s Conclusions Natural selection had no human involvement.
All life goes through a struggle to exist.
The genes that allowed an organism to survive would be passed to another generation.
Over time a new species would develop.

12. Evidence of Evolution #1
Fossil Record
Showed through the process of time the animals that existed on the planet.
By comparing fossils and rock layers one can find the relationships in changing life.

13. Evidence: Fossils

14. Evidence of Evolution #2
BIOGEOGRAPHY: Geographic Distribution
Different continents had different species of animals.
The reason is because each species descended from different animals.
However if the species had the same conditions on two different continents they evolved the same.

15. Geographic Distribution
Beaver
Beaver
Muskrat
Beaver and Muskrat
Coypu
Capybara
Coypu and Capybara
NORTH AMERICA
Muskrat
Capybara
SOUTH AMERICA
Coypu

16. Evidence of Evolution #3
COMPARATIVE ANATOMY
Homologous structures
Structures in different species that share similar structure, function, or both.
These show that the species have a common ancestor.

17. Homologous Body Structures
Turtle
Alligator
Bird
Mammal
Ancient lobe-finned fish

18. Homologous Structures

19. Vestigial structures- A structure that has no function in a present-day organism but was probably useful to an ancestor.
Natural selection does not get rid of the organ.

20. Evidence of Evolution #4
EMBRYOLOGY
Embryo- the earliest stage of growth of an organism.
Fish chicken rabbit human

21. Embryology

22. Evidence of Evolution #5
MOLECULAR BIOLOGY
DNA and proteins are shared in common between related individuals.
Species that are closely related will have higher amounts of their DNA and proteins in common. Ex – Humans and chimps share 99% of their DNA!

23. A summary of Darwin’s Theory
1. Individual organisms are different and some of these difference can be inherited.
2. Organisms produce more offspring than can survive in an environment. The organisms that do not survive do not reproduce.

24. A summary of Darwin’s Theory
3 Because more organisms are produced than survive, they compete for resources.
4. Organisms has different advantages and disadvantages in their struggle for existence. The organisms that are best suited to their environment survive and reproduce a lot more.
5. Species alive today are descended with modifications from ancestral species that lived in the past.