Transcript No Slide Title

Interest Grabber
Section 15-1
A Trip Around the World
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, such as finches and
tortoises.
1. On a sheet of paper, list five animals that you have encountered in
the past two days.
2. How do these animals differ from the finches and tortoises of the
Galápagos Islands? (Examine Figures 15–3 and 15–4 in your
textbook.)
3. Propose a hypothesis to account for the differences between the
animals that you observed and the finches and tortoises of the
Galápagos Islands.
Section Outline
Section 15-1
15–1
The Puzzle of Life’s Diversity
A. Voyage of the Beagle
B. Darwin’s Observations
1. Patterns of Diversity
2. Living Organisms and Fossils
3. The Galápagos Islands
C. The Journey Home
Giant Tortoises of the Galápagos
Islands
Section 15-1
Pinta
Pinta Island
Tower
Marchena
Intermediate shell
Fernandina
James
Santa Cruz
Isabela
Santa Fe
Hood Island
Floreana
Isabela Island
Dome-shaped shell
Hood
Saddle-backed shell
Figure 15–1 Darwin’s Voyage
Section 15-1
Interest Grabber
Section 15-2
My, How You’ve Changed!
Prior to the 1800s, life scientists knew that living things changed over
generations. They just didn’t know how these changes were brought about.
1. Divide a sheet of paper into two columns and title the first one Inherited
Characteristics. Title the second column Acquired Characteristics. In
the first column, list the characteristics that you believe you have
always had. For example, you may have brown eyes or curly hair.
2. In the second column, list your acquired characteristics. For example,
you may have learned how to play a musical instrument.
3. Which of the items in your lists do you think you might pass on to your
children? Explain your answer.
Section Outline
Section 15-2
15–2
Ideas That Shaped Darwin’s Thinking
A. An Ancient, Changing Earth
1. Hutton’s Theory of Geological Change
2. Lyell’s Principles of Geology
B. Lamarck’s Theory of Evolution
1. Tendency Toward Perfection
2. Use and Disuse
3. Inheritance of Acquired Traits
4. Evaluating Lamarck’s Theory
C. Population Growth
Movement of Earth’s Crust
Section 15-2
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.
Figure 15–7 Lamarck’s Theory of
Evolution
Section 15-2
Interest Grabber
Section 15-3
When Is a Flipper a Wing?
All living things are related. Some relationships are easy to see—
your pet cat may not roar like a lion, but it clearly resembles one.
Other relationships are less obvious.
Interest Grabber continued
Section 15-3
1. On a sheet of paper, construct a table that has five columns and six
rows. In the columns, write the following heads: Animal Group,
Example, Legs, Fins, and Tail. Then, place the following animal groups
in their own row: Mammal, Bird, Fish, Amphibian, Reptile, and Insect.
2. Give one example for each group, and then fill in the information
for that example. For Legs, write in the number of legs that each
animal has. Do animals with fins have legs? Do animals with wings
have legs? If so, how many?
3. Can you tell from your table if a fish is more closely related to a bird
or to an amphibian? Explain your answer.
Section Outline
Section 15-3
15–3 Darwin Presents His Case
A. Publication of On the Origin of Species
B. Natural Variation and Artificial Selection
C. Evolution by Natural Selection
1. The Struggle for Existence
2. Survival of the Fittest
3. Descent With Modification
D. Evidence of Evolution
1. The Fossil Record
2. Geographic Distribution of Living Species
3. Homologous Body Structures
4. Similarities in Early Development
E. Summary of Darwin’s Theory
Concept Map
Section 15-3
Evidence of
Evolution
includes
The fossil record
Geographic
distribution of
living species
Homologous
body structures
Similarities
in early
development
which is composed of
which indicates
which implies
which implies
Physical
remains of
organisms
Common
ancestral
species
Similar genes
Similar genes
Figure 15–14 Geographic Distribution
of Living Species
Section 15-3
Beaver
Beaver
NORTH
AMERICA
Muskrat
Muskrat
Beaver and
Muskrat
Coypu
Capybara
Capybara
SOUTH
AMERICA
Coypu
Coypu and
Capybara
Figure 15–15 Homologous Body
Structures
Section 15-3
Turtle
Alligator
Typical primitive fish
Bird
Mammals