1. Change Over Time …

2. Evolution Objectives: Define evolution.
How do we know the living world has changed over time?
What can you learn from fossils?
Define natural selection.

3. Why Change?
Changes in the environment can have an impact on living organisms
Three options:
Adapt – change and find a way to survive in the new situation
Move – migrate to a new location; either temporarily or permanently
Extinction – failure to adapt

4. Evolution The process of biological change over time
Organisms of the present differ from ancestors of the past
Charles Darwin

5. Evolution – How do we know?
Some organisms evolve or change very quickly and can be observed
Examples: bacteria and insects
Fossils are evidence of past life
Examples: bones, teeth, footprints, shells, feather impressions, etc.

6. Fossils Early organisms were simple in form
Organisms became more complex over time
The diversity of life has increased over time
New organisms appear and others die off (extinct)

7. Evolution – How do we know?
Equus – “modern horse”
300 cm tall
Today
Hyracotherium – “early horse”
20 cm tall
55 million years ago

8. Why do living things evolve?
Response to changes in the environment
Ex. changes in climate, vegetation, or introduction of new organisms
Some organisms have variations that allow them to adapt to changes
Ex. genetic mutations

9. Natural Selection
Organisms with favorable variations are more likely to:
survive
reproduce
produce offspring with these variations

10. Artificial Selection
Human beings have been using evolution for centuries!!
Thousands of years ago wolves were taken as pets by humans. Each culture had specific traits they wanted these animals to have. Today we have hundreds of different types of dogs that are extremely different from one another