1. Developing the Theory of Evolution
Chapter 16
Developing the Theory of Evolution

2. How did life start ?

3. Origins: Early Ideas Spontaneous Generation Spontaneous Combustion
Redi – Redi Experiement
Rejected mid-1800’s
Spontaneous Generation
Theory of Biogenesis
Louis Pasteur
Only living organisms can give rise to other living organisms.

4. Origins: Modern Ideas Primordial Soup? Oparin & Haldane 1920’s
Earth’s Atmosphere
Mix of gases
Lightning – energy source

5. Origins: Modern Ideas Photosynthesizing Prokaryotes Cellular Evolution
First Cells –
Prokaryotes
Modern prokaryotes – archaea
Live in extreme environments
Photosynthesizing Prokaryotes
Oxygen absent til 1.8 bya
Produced oxygen
Ozone layer
Improved conditions for Eukaryotic cell development

6. Origins: Modern Ideas Miller-Urey Experiment
Organic molecules could be produced from gases.

7. 3 World Changing Biology Experiments

8. Origins: Modern Ideas Endosymbiont Theory
Eukaryote “ate” prokaryote or bacteria
Formed symbiotic relationships
Prokaryote became the mitochondria
Bacteria became chloroplasts
Video
Widely endorsed – do not know exact early steps.

9. Lamarck’s Theory of Evolution
Inheritance of acquired characteristics
Proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime
These traits could then be passed on to their offspring
Over time this led to new species

10. Lamarck’s Theory of Evolution
Use & Disuse –
Organisms could change the size or shape of organs by using them or not using them
Blacksmiths & Their Sons
(muscular arms)
Giraffe’s Necks
(longer from stretching)

11. copyright cmassengale

12. If Lamarck was right, then you should be able to work out and have stronger kids

13. Lamarck’s Mistakes
Lamarck Did NOT Know how traits were inherited (Traits are passed through genes)
Change Through Mutation Occurs Before An Organism Is Born

14. Charles Darwin (1809 – 1882)

15. copyright cmassengale
Voyage of the Beagle
Charles Darwin
Born Feb. 12, 1809
Joined Crew of HMS Beagle, 1831
Naturalist
5 Year Voyage around world
Avid Collector of Flora & Fauna
Astounded By Variety of Life
copyright cmassengale

16. Darwin returned 5 years later in 1836
Darwin Left England in 1831
Darwin returned 5 years later in 1836

17. The Galapagos Islands
Small Group of Volcanic Islands km West of South America
Very Different Climates
Animals On Islands Unique
Tortoises
Iguanas
Finches

18. The Galapagos Islands
Island species varied from mainland species & from island-to- island species
Each island had long or short neck tortoises

20. The Galapagos Islands Finches on the islands
Resembled a mainland finch
More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…)
Finches had different types of beaks adapted to their type of food gathering

21. Darwin’s Observations
Patterns of Diversity
Unique Adaptations
Species Not Evenly Distributed
Australia, Kangaroos, but No Rabbits
S. America, Llamas

22. Definition
Evolution is the slow , gradual change in a population of organisms over time.

23. Publication of “On The Origin of Species”
Upon His Return To England, Darwin Developed His Observations Into The Theory of Evolution

24. Darwin Finch Activity Part 1
Darwin’s Finches
Darwin Finch Activity Part 1

26. Darwin Finch Sort Activity
Darwin’s Finches
Darwin Finch Sort Activity

27. Darwin’s Finches
The Beak of the Finch

29. Darwin’s Finches
Sorting Finch Species

30. What Darwin Never Knew

31. What Did T-Rex Taste Like?