1. Evolution and Natural Selection
By: Mr. Kauffman

2. Outline Evolution Early Ideas Charles Darwin Darwin’s Observations
Darwin’s Finches
Natural Selection
Factors That Lead To Evolution
Evidence Of Evolution
What If You Don’t Evolve
Threatened vs. Endangered vs. Extinct
Causes Of Extinction

3. Evolution
Evolution: change in inherited characteristics of a species over time
What does that mean?
A living thing develops new traits that can be passed from parents to their offspring
Takes a very long time
What is a species?
A group of organisms with similar characteristics and the ability to produce offspring
Example: golden retrievers and german shepherds are the same species (dog)
Non-example: dogs and cats are different species

4. What are 3 similarities and 3 differences you see within this species?

5. Early Ideas Theory of Acquired Characteristics
1809 – idea developed by Jean Baptiste de Lamarck
Said that organisms can develop characteristics during their lives and pass those characteristics on to their offspring
Example: giraffes grew longer necks by stretching to reach food, then their babies were born with longer necks

7. Early Ideas Why was the Theory of Acquired Characteristics wrong? + ≠
Only genetic traits (DNA) can be passed on to offspring
Traits developed during a lifetime can’t be passed on to offspring
Proof: parents who build up a lot of muscle by working out won’t have really strong babies + ≠

8. Charles Darwin
A British naturalist who sailed around the world in 1831
Explored the Galapagos Islands
20 isolated islands
600 miles off the coast of South America

9. Darwin’s Voyage

10. Galapagos Islands

11. Darwin’s Observations
Observed many unique organisms on the Galapagos Islands
He noticed that the organisms on the Islands looked similar to the ones from South America
Darwin stated that the organisms on the Galapagos Islands must have evolved from the ones from South America
Some organisms traveled to the Islands
They then got stuck on the Islands
Eventually they developed new characteristics to survive on the Islands

12. Galapagos Islands

13. Galapagos Wildlife

14. Galapagos Tortoises

15. Galapagos Tortoises 15

16. Darwin’s Finches Darwin found 13 different species of finches (birds)
All are virtually identical except for:
Beak size and shape
Food they eat
All 13 also looked very similar to 1 species found on South America
Darwin stated that the 13 different species on the Galapagos Islands all evolved from the 1 species on South America

17. Galapagos Finches

18. Galapagos Finches

19. Natural Selection
Darwin’s theory for how organisms evolve is called Natural Selection
Based on his observations from the Galapagos Islands
What does the theory of Natural Selection mean?
Organisms with traits well suited to an environment are more likely to survive and pass on those traits to their offspring

20. Natural Selection
What is the key determining factor in natural selection?
Environment
Organisms must adapt to their environment in order to survive
Good adaptations:
Poisons/toxins
Camouflage
Thick fur
Ability to conserve water

21. What Traits Would Be Beneficial?1.

22. What Traits Would Be Beneficial?2.

23. What Traits Would Be Beneficial?3.

24. Natural Selection
Adaptation: any variation in an organism that makes it better suited to survive in its environment
The variations are caused by mutations in DNA
Mutations are random mistakes in DNA
Most have no effect = organism stays the same
Some can be harmful = organism dies quickly
Some can be beneficial = organism has better chances to survive

25. Mutations