1. Natural Selection What does the word “evolve” mean? To change
Does evolution happen quickly or slowly?
Very slowly- over thousands or millions of years
Does evolution result in new species?
Sometimes
Did humans come from monkeys?

2. Evolution
Fossil records show that living things have in fact changed over time (evolution)
When we say Evolution, we don’t mean one individual changing over the course of it’s lifetime. We mean a species changing over many many years
Why did they change?
How did they change?

3. Evolution by Natural Selection
Evolution (change in a species over many years) occurs because of and through a process called natural selection.
Peppered Moths!!!

4. Peppered Moths
Before Pollution
After Pollution

5. Peppered Moths
Volunteers to play the game?

6. 1. More offspring are produced than can survive

7. 1. More offspring are produced than can survive
This means that there is a struggle for existence and not every organism will survive long enough to reproduce
This is caused by competition for food, spaces, and other limited resources

8. Was this true for the peppered moths?

9. 2. There is an inheritable variation ……

10. 2. There is an inheritable variation ……
This means that there is a variety of inherited traits. Any inheritable trait that helps an organism survive and reproduce is called an adaptation
Examples include body parts like a duck’s foot, colors like a camouflaged insect, or behaviors like how prey avoid being eaten

11. Was this true for the peppered moths?

12. 3. Survival of the fittest

13. 3. Survival of the fittest
This means that only the individuals that have the greatest fitness survive. Fitness means how well an organism can survive and reproduce in its environment
An example is grasshoppers. They come in two colors: green and yellow. In a grassy environment, the green ones are more “fit” because they are less likely to get eaten and more likely to reproduce

14. Was this true for the peppered moths?

15. 4. Natural Selection

16. 4. Natural Selection
The process by which organisms with variations most suited to their local environment survive and leave more offspring
This doesn’t make organisms better- it just eliminates organisms who do not have traits that are well suited for that environment
If the environment changes, then perhaps different traits will be better and more likely to be passed down

17. 4. Natural Selection
The process by which organisms with variations most suited to their local environment survive and leave more offspring
This doesn’t make organisms better- it just eliminates organisms who do not have traits that are well suited for that environment
If the environment changes, then perhaps different traits will be better and more likely to be passed down