1. Do Now: Compare the two graphs below.
How are they similar and different?
Darwin and His Theory
5/9/2018
Speciation Dynamics - Gradualism or Punctuated Equilibrium?
Time
G. Podgorski, Biol. 1010 1

2. Gradualism

3. Punctuated Equilibrium

4. Gradualism

6. Gradualism or Punctuated Equilibrium

8. Change is continuous and slow for many years
Change occur during a brief period of time
New species evolve through the accumulation of many small changes
Species exist unchanged for many years, then many changes occur in a brief period of time
Supported by transitional fossil forms
Supported by lack of intermediate fossil forms

9. Gradualism suggests that the changes are slow and continuous, while
Punctuated equilibrium suggests there are long periods of no change an some short periods of rapid change.
Gradualism suggests that the accumulation of small variation results in new species
The presence of transitional or intermediate form in fossils indicates that
evolutionary change may occur in a time frame known as gradualism.
The lack of intermediate forms in the fossil record indicates that evolutionary change may occur as punctuated equilibrium proposes.

10. Punctuated Equilibrium
Gradualism
Punctuated Equilibrium
Change is continuous and slow for many years
Change
Change occur during a brief period of time
New species evolve through the accumulation of many small changes
Species
Species exist unchanged for many years
Supported by transitional form
Fossil record
Supported by lack of intermediate forms