1. Ch. 15-Darwin's Theory of Evolution
While on his voyage around the world aboard the H.M.S. Beagle, Charles Darwin spent about one month observing life on the Galápagos islands. There, he encountered some unique animals. But these unique creatures were obviously related to ones he knew, namely finches and tortoises. And as he looked closely at them, he noticed they were not as different from each other as they first appeared.

2. Ch. 15-Darwin's Theory of Evolution
On the next screen, use the starboard to fill in the Venn diagram to compare and contrast finches to tortoises. See if you can see how these very different creatures have some very real similarities.

4. Ch. 15-Darwin's Theory of Evolution
15–1 The Puzzle of Life’s Diversity
A. Voyage of the Beagle

5. Ch. 15-Darwin's Theory of Evolution
B. Darwin’s Observations-Patterns of Diversity-plants and animals adapt over time to their environment. The Galapagos Islands brought this fact home to Darwin.
Pinta Island Intermediate shell
Pinta
Isabela Island
Dome-shaped shell
Hood Island
Saddle-backed shell
Hood
Floreana
Santa Cruz
James
Isabela
Tower

6. Living Organisms and Fossils
Ch. 15-Darwin's Theory of Evolution
Living Organisms and Fossils
Studying fossils show links between living organisms and ones long extinct.

7. Ch. 15-Darwin's Theory of Evolution
MY! HOW YOU’VE CHANGED!
On the next slide, use Starboard to fill in your inherited and acquired characteristics.
When you have finished filling in the table, discuss the following questions:
A. Which of the items in your list will your children inherit from you?
B. Why will they inherit these characteristics from you?

8. Ch. 15-Darwin's Theory of Evolution
Inherited
Acquired

9. Ch. 15-Darwin's Theory of Evolution
15–2 Ideas That Shaped Darwin’s Thinking
A. Hutton and Geological Change-Hypothesized that geological forces changed the earth over millions of years.

10. Ch. 15-Darwin's Theory of Evolution
B. Lyell’s Principles of Geology-Past processes that shaped the earth continue today.
Volcanoes continue to erupt throughout the world, destroying and creating simultaneously in gigantic explosions of hot gas and molten rock.

11. Ch. 15-Darwin's Theory of Evolution
C. Lamarck’s Evolution Hypotheses
1. Tendency Toward Perfection
2. Use and Disuse
3. Inheritance of Acquired Traits

12. Ch. 15-Darwin's Theory of Evolution
4. Evaluating Lamarck’s Hypotheses
PRO
CON

13. Ch. 15-Darwin's Theory of Evolution
D. Thomas Malthus-Populations grow slowly at first and then exponentially until all available resources are at maximum use. The population will then crash as organisms die off from disease and starvation.

14. Quoted to show Malthus tremendous influence on Darwin’s ideas.
Ch. 15-Darwin's Theory of Evolution
"In October 1838, …I had begun my…inquiry, I happened to read …Malthus on Population, …being well prepared to appreciate the struggle for existence which everywhere goes on… it at once struck me that under these circumstances (what Malthus described)… favorable variations would…be preserved, and unfavorable ones…destroyed. The results…would be the formation of a new species….I had at last got a theory by which to work".
Charles Darwin, from his autobiography. (1876)
Quoted to show Malthus tremendous
influence on Darwin’s ideas.

15. Ch. 15-Darwin's Theory of Evolution
How alike are they?
Group
Example
Wings
# legs
Tail
Fish
Amphibian
Reptile
Bird
Mammal
Insect

16. Ch. 15-Darwin's Theory of Evolution
15–3 Darwin Presents His Case
Publication of On the Origin of Species-
Published in years after Darwin’s voyage on the Beagle
For those who want to know, here is the link to the on-line text of Darwin’s famous and controversial book.
Go ahead and read it for yourself.

17. Ch. 15-Darwin's Theory of Evolution
Inherited Variation and Artificial Selection
Members of each species vary from one another in important ways.
This inherited variation can be used by breeders to create organisms with other characteristics.
b. If breeders can “artificially select” the traits they want, Darwin proposed that there was a “natural selection” in place on Earth.
c. This “natural selection” permitted only those individuals with inherited traits that allowed them to survive to reproduce and produce offspring.

18. Ch. 15-Darwin's Theory of Evolution
Excellent link on Evolution:
C. Evolution by Natural Selection
The Struggle for Existence
a. More offspring are born than can survive.
2. Survival of the Fittest
a. Those offspring that can survive do so because their inherited variations in genes permit their survival

19. Ch. 15-Darwin's Theory of Evolution
3. Descent With Modification
Natural selection produces organisms that have different structures, niches, habitats.
Species today look different from their ancestors.
Each living species has descended, with changes, from other species over time.
Implies that all living organisms are related to one another.

20. Ch. 15-Darwin's Theory of Evolution
D. Evidence of Evolution
The Fossil Record
Geographic Distribution of Living Species

21. Ch. 15-Darwin's Theory of Evolution
Homologous Body Structures
4. Similarities in Embryos
Fish
Chicken
Pig
Human

22. Ch. 15-Darwin's Theory of Evolution
Summary of Darwin’s Theory
Individual organisms differ. These differences are inherited
Organisms produce more offspring than can survive.
There is competition for limited resources.

23. Ch. 15-Darwin's Theory of Evolution
Individuals best suited to their environment survive and reproduce most successfully. This process of natural selection causes species to change over time.
Species alive today are descended from species that lived in the past.
F. Evolutionary Theory Since Darwin

24. Ch. 15-Darwin's Theory of Evolution
F. Evolutionary Theory Since Darwin
Scientific advances in many fields of biology, along with geology and physics, have confirmed most of Darwin's hypotheses.
Important questions still remain:
How new species arise
Why do species become extinct.
How did life began on our planet.