1. The Puzzle of Life’s Diversity

2. Charles Darwin sailed around the world on the H. M. S. Beagle in 1831.
Evolution: how modern organisms have descended from ancient organisms

3. Darwin’s Observations
Patterns of Diversity: plants and animals well suited to their environments
Why 2 similar ecosystems contain different animals
Fossils: preserved remains of ancient organisms.
Why species disappeared & relation to living species
The Galápagos Islands: the characteristics of many animals and plants varied noticeable among the different islands

4. Important Scientists: Hutton & Lyell
the Earth is many millions of years old
the processes that changed Earth in the past are the same processes that operate in the present

5. Important Scientists: Malthus
unchecked human population growth would lead to insufficient living space and food
Forces Against Growth
War
Famine
Disease

6. Lamarck’s Evolution Hypothesis
Through selective use or disuse of organs, organisms acquired or lost certain traits
Traits could then be passed on to offspring.
Led to change in a species.
Ideas are flawed; traits are inherited and behavior has no effect heritable characteristics.
But organisms are adapted to their environment.

7. Darwin

8. Darwin Completed 25 years of research
Published On the Origin of Species
Proposed Natural Selection
mechanism for evolution

9. Evolution By Natural Selection
Struggle for existence: member of each species compete regularly for food, living space, and other necessities
Survival of the Fittest
better suited  survive and reproduce more
not well suited  die or leave few offspring

10. Fitness: ability to survive & reproduce
Successful adaptations allow organisms to become better able to survive and reproduce.
Natural Selection
changes in a population’s inherited characteristics
increase a species’ fitness

11. Evidence of Evolution Fossils: observe changes over time
Geographic Distribution: Similar species descended with modifications from a common ancestor
Similar embryo development

12. Embryo Development

13. Evidence of Evolution
Homologous Structures: structures that have different mature forms but develop from the same embryonic tissue
vestigial organs: reduced organs are traces of homologous structures
miniature legs/tails
appendix