1. Evolution

2. Darwin’s Epic Journey
Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.

3. Darwin’s Epic Journey
Darwin was invited to sail on the HMS Beagle’s five-year voyage mapping the coastline of South America.
Darwin planned to collect specimens of plants and animals on the voyage.

4. Observations Aboard the Beagle
What three patterns of biodiversity did Darwin note?
1. Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe
***Species vary globally
2. Darwin noticed that different, yet related, animal species often occupied different habitats within a local area.
***Species vary locally
3. Darwin noticed that some fossils of extinct
animals were similar to living species.
***Species vary over time

5. Species Vary Globally
Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe.
These birds all live in grassland habitats around the globe
Rheas Ostrich Emu
South America Africa Australia

6. Species Vary Locally
These islands are close to one another, yet they have different ecological conditions.
Darwin observed that different islands had different varieties of Finches. Their beak shape differed based on what their diet, (fruit, nuts, insects, etc).

7. Species Vary Over Time
Darwin noticed that some fossils of extinct animals were similar to living species.
The long-extinct glyptodont, a giant armored animal similar to the armadillo.

8. Scientists that contributed ideas to the history of the Earth.
Hutton and Lyell: concluded that Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present.
Hutton: there is a connection between geological processes (erosion, uplift, etc) and geological features (mountains, valleys, etc)
Lyell: laws of nature are consistent over time (uniformitarianism)

9. Lamarck’s Evolutionary Hypotheses
Lamarck : organisms could change during their lifetimes by selectively using or not using various parts of their bodies
Traits altered by an individual organism during its life are called acquired characteristics.
**First person to suggest organisms change over time**
How do species change over time????
Individuals could pass these acquired traits on to their
offspring, enabling species to change over time.

10. Lamarck’s Ideas
According to Lamarck: a black-necked stilt could have acquired long legs because it began to wade in deeper water looking for food. As the bird tried to stay above the water’s surface, its legs would grow a little longer.

11. Evaluating Lamarck’s Hypotheses
Lamarck’s Hypothesis is incorrect in several ways
Species do not become “better” somehow over time
Evolution does not progress in a
predetermined direction.
Traits acquired by individuals during
their lifetime cannot be passed on
to offspring.

12. Population Growth Thomas Malthus:
Resources and space will run out if a population grows unchecked (exponentially)
The forces that prevent population growth include war, famine, and disease.

13. Artificial Selection
Darwin knew that variation occurs in wild species as well as in domesticated plants and animals.
He recognized that natural variation was very important because it provided the raw material for evolution.
Darwin put artificial selection to the test by raising and breeding plants and fancy pigeon varieties.

14. Alfred Russell Wallace
“Father of Biogeography”
Independently conceived the
theory of evolution by
natural selection.
Showed courtesy in letting
Darwin know he was
publishing so that they
could publish together.

15. In 1859, Darwin published his first complete work on evolution: On the Origin of Species.