1. EVOLUTION
Chapter 15

2. Charles Darwin

3. Darwin’s Theory of Evolution
Evolution: Change over time, This is why certain animals blend in or have long beaks
A scientific theory is a well-supported testable explanation that occurred in the natural world

4. Voyage of the Beagle

6. Patterns of Diversity
Darwin visited Argentina and Australia which had similar grassland ecosystems.
those grasslands were inhabited by very different animals.
neither Argentina nor Australia was home to the sorts of animals that lived in European grasslands.

7. Patterns of Diversity
Darwin posed challenging questions.
Why were there no rabbits in Australia, despite the presence of habitats that seemed perfect for them?
Why were there no kangaroos in England?

8. Living Organisms and Fossils
Darwin collected the preserved remains of ancient organisms, called fossils.
Fossil: Petrified (Turned to stone) organic material
Some of those fossils resembled organisms that were still alive today.

9. Fossils

10. The Galapagos Island
The smallest, lowest islands were hot, dry, and nearly barren-Hood Island-sparse vegetation
The higher islands had greater rainfall and a different assortment of plants and animals-Isabela- Island had rich vegetation.

12. Animals found in the Galapagos
Land Tortoises
Darwin Finches
Blue-Footed Booby
Marine Iguanas

13. Animals

14. The Journey Home
Darwin Observed that characteristics of many plants and animals vary greatly among the islands
Hypothesis: Separate species may have arose from an original ancestor

15. Lamarck’s Evolution Hypothesis
By selective use of certain organs, organisms lose or gain traits.
These traits get passed on to their offspring

18. Lamarck’s Evolution Hypothesis
Proposed that by selective use of certain organs, organisms lose or gain traits. These traits get passed on to their offspring

19. Lamarck’s Evolution Hypothesis
Proposed that by selective use of certain organs, organisms lose or gain traits. These traits get passed on to their offspring
What’s wrong with this hypothesis?

20. What they forgot Did not account for how the traits were inherited.
Animals behavior does not determine their inherited traits.

21. Natural Selection
Animals best adapted to environment will survive and reproduce

22. Natural Selection

23. Natural Selection

24. Artificial Selection
Nature provides the variation, humans select what we find useful
Those plants or animals pass on those traits

25. Struggle for Existence

26. Struggle for Existence
Members of each species compete regularly to obtain food, living space and other resources
Animals with best Fitness, would adapt better and increase chances of survival

27. Common Descent
Over Millions of years, organisms evolved from same ancestor

28. Homologous Structures
Structures that have different forms but develop from same embryonic tissue

31. Vestigial Organs
Organs that no longer serve a purpose, but at one point did.
Appendix, tails, toes