1. Evolution and Natural Selection
How species change over time

2. Evolution and Natural Selection
Genetic variations are passed on through reproduction
Natural selection leads to evolution
Our understanding of evolution has changed over time

3. Evolution
The theory that organisms have changed (evolved) over time.

4. Natural Selection
The theory that states that those organisms best adapted to their environment have a better chance of surviving and reproducing.

5. Charles Darwin

6. Scientist credited with the
Theory of Evolution & Natural Selection
Voyage of the HMS Beagle –
a 5 year voyage to South America and the South Pacific, collecting specimens, making observations and keeping a scientific journal of his findings.

7. Voyage of the Beagle What did Darwin find?
The finches on each island in the Galapagos had different types of beaks.
Discuss the graphic with the students.

8. Voyage of the Beagle What did Darwin find?
The tortoises on each island in the Galapagos had different types of shells.

9. What was Darwin’s hypothesis?
Darwin hypothesized that organisms had adapted to their particular environments and changed over time.
Darwin published his
research in 1859

10. Natural Selection
For natural selection to occur, there must be at least two varieties of a species.
For example: the peppered moth
Industrial Melanism= Adaptation

11. Peppered Moths
At the beginning of the Industrial Revolution in England, coal burning produced soot that covered the countryside in many areas

12. What do you think happened?

13. Peppered moth activity
You will simulate how changes in genetic traits change over several generations have occurred through natural selection
Materials: Prey circle papers, colored pen or marker, journals and stopwatch
Predator-checks off prey circles
Time keeper-15 seconds
Everyone records

14. What does your data show about how prey are selected by predators?
What moth coloration is the best adaptation for a light colored background? Dark colored background? How do you know( justify your evidence from the trials)?
Based on the surviving “prey circles” what would you expect the next generation of moths to look like after trial 1? After trial 2? After trial 3?

15. Evolution/Natural Selection
White moths became easier to see, while the black moths became harder to see. The black moths were more likely to survive and pass on the gene for dark color to their offspring.
Over time, the black moths
have become more common.

16. Evidence for Evolution: Common Ancestry
Common Ancestry: If species evolved from a common ancestor, then they should share common anatomical traits
Hawaiian Honeycreeper: family of
birds in Hawaii that have similar
skeletons and muscles, indicating
they are closely related.
Over time, their common ancestor evolved
into several species, each with a specialized bill for eating certain foods. Just like Darwin’s finches on the Galapagos!

17. Evidence for Evolution: Vestigial Organs
Some organisms have structures or organs that no longer have a useful function.
These structures or organs may have been useful to the ancestors of a species, but over time have evolved into what we term vestigial organs.

18. Examples of Vestigial Organs
Kiwi (flightless bird)
Whales (hind leg bones)
Humans (tailbone, appendix)

19. Evidence for Evolution Fossils
Fossils provide a look
into the past
Scientists can trace how
a species has evolved
by studying fossils