1. Early Ideas About Evolution

2. Evolution
is the process of biological change
by which descendants come to
differ from their ancestors.

3. Divine creation
Species are unchanged

4. CHARLES DARWIN father of evolution

5. Early scientists proposed ideas
about evolution which influenced Darwin.
Linnaeus (1700s) developed
a classification system
for all types of organisms
based on similarities.
Buffon (1700s) based on fossil evidence,
he proposed that species shared ancestors
instead of arising separately.
He suggested that the Earth was much older.

6. Incorrect! WHY? Erasmus Darwin (1760’s)
All living things were descended
from a common ancestor
and more complex forms
arose from less complex forms.
Jean-Baptist Lamarck proposed that changes in the environment caused organism’s behavior to change, leading to greater or lesser use of a structure or organ. The structure would increase in size because of use or decrease in size because of disuse.
Incorrect!
WHY?

7. Theories of geologic change set the stage for Darwin’s theory.
The study of fossils
by Cuvier (1800’s)
led to the idea that organisms
could become extinct.
Different species from
adjacent areas would
move into the newly
vacated area.

8. Geologist James Hutton (late 1700’s)
proposed that the changes he observed in landforms
resulted from small changes over a long period of time (gradualism).
Charles Lyell (1830’s) Earth was ancient…millions of years old.
Theory of uniformitarianism –
geologic processes that shape Earth are uniform through time.
These geological processes are slow but cause great change.

9. The observations that Darwin made on a voyage of HMS Beagle ( ) led to his ideas about evolution.  

10. Darwin observed various adaptations
of plants and animals that inhabited
such diverse environments
as jungles, grasslands, and deserts.

11. He also noted that plants and animals
in South America closely resembled
species there rather than species in Europe.

12. Darwin visited the Galapagos Islands, 500 miles off the coast of Ecuador.

13. Darwin was struck by the variation of traits
between species of finches in the Galapagos Islands.
The most striking difference
among them are their beaks.

14. Darwin observed that finches found on the Galapagos
resembled species living on the mainland.
Darwin observed that finches found on one island
looked different from those on nearby islands.

15. Their beak shapes seemed well suited to their diets.
These observations led Darwin to realize that species may
somehow be able to adapt to their surroundings.
An adaptation is a heritable characteristic that increases an
organism’s ability to survive and reproduce in its environment.

16. Darwin hypothesized that the Galapagos
had been colonized by finches that had strayed
from South America and had then
diversified on the various islands.

17. Evolution of Life