1. CHAPTER 14: EARTH’S HISTORY

2. Earth’s History Earth’s history is long and fascinating.
There have been great biological and geological changes

3. Fossil Records
The fossil record provides strong evidence of the evolution of life
Triceratops

4. Nicholas Steno
Earth’s history has been unveiled by scientists applying the tools of critical thinking
Nicholas Steno was a Danish theologian
First to suggest that fossils had once been
living organisms
Developed the Principles of Original Horizontality,
Superposition, and Lateral Continuity

5. James Hutton Scottish naturalist and physician Father of geologic time
Proposed that geologic time was indefinitely long
Believed the Earth was self-renewing (basis of rock cycle)
Formulated the principle of uniformitarianism

6. Charles Lyell British lawyer Father of Modern Geology
Wrote Principles of Geology
Popularized Principle of Uniformitarianism
Developed the Principles of Cross-cutting Relationships and Inclusions

7. Charles Darwin English naturalist and geologist
Studied Lyell’s Principles of Geology
Wrote On the Origin of Species by Means of Natural Selection
Credited with the Theory of Evolution

8. Natural Selection
All living things develop over time from a very few simple forms
All individuals survive equally
Conditions change and only well-adapted individuals survive
New generation is dominated by well-adapted individuals
Can you think of a change in conditions that might lead to natural selection?

9. Fossils
Fossils are the remains of animals and plants, or traces of their presence, that have been preserved in the crust.
Fossils preserve a record of past life.

10. How Are Fossils Made?
Fossilization is the process that turns a once-living thing into a fossil.
The Fossil record is biased. Rapid burial is required. In most cases just shell, teeth, and bones are preserved.
Preservation is typically by: replacement or formation of a mold or cast.

11. Rare, soft part preservation
Brachiopod shells
Rare, soft part preservation
(dinosaur skin)
Are these molds or casts or both? Is there evidence of replacement here?

12. There are several lines of evidence for evolution
Phylogeny
Phylogeny is the history of organismal lineages as they change through time. What are some of the changes evident in the phylogeny of the horse?

13. Homologous Structures

14. Vestigial Structures
How does the existence of vestigial structures support the concept of evolution?

15. Embryology
Even distantly related organisms have similar embryonic forms that can be traced back to their evolutionary history

16. Molecular biology also provides evidence of evolution
Changes within separate populations of the same species result in new species through natural selection.
Genetic Mutation
(random changes to RNA or DNA)
Genetic Variation
(differences in inherited traits)

17. Molecular biology documents the relationship of living organisms to their ancestors

18. Parasitic microbes, viruses, bacteria ... all evolve!

19. Extinctions
Mass extinctions are dramatic events in the otherwise slow process of evolution
Which of the Phanerozoic extinctions had the greatest impact on marine organisms? Which one lead to the extinction of the terrestrial dinosaurs?

20. Extinction
During a mass extinction large numbers of species die out within a relatively short period of time.

21. There are various hypotheses for each mass extinction ...

22. Geologic Time Scale
The Geologic Time Scale is the “calendar” of events in Earth’s history
Geologic Column Drag and Drop
Geologic Column Drag and Drop Animation

23. Hadean Eon Heating of the interior Magma “ocean” “Iron Catastrophe”
Eventual cooling
Earliest crust and oceans
Ended ~ 3.8 bya
Began ~ 4.6 bya
Extraterrestrial barrage
Atmosphere rich in methane, ammonia and carbon dioxide
Why was the Earth so much hotter during the Hadean than it is now?

24. Archean and Proterozoic cratons (i.e., continent crustal blocks)
The Archean and Proterozoic Eons lasted from 3.8 million to 542 million years ago
Archean and Proterozoic cratons (i.e., continent crustal blocks)

25. Archean Eon
Atmosphere noxious to modern organisms (methane, ammonia, carbon dioxide, and water vapor)
More extraterrestrial bombardment
More volcanic outgassing
Continental Cratons form
Abundant life first appears (stromatolites)
Photosynthesis initiated
The atmosphere of the Archean would have been noxious to us. What component of our atmosphere would have been noxious to the Archeans?
Ancient and modern stromatolites

26. Proterozoic Eon
Continents develop, clustered together (Rodinia) in the southern hemisphere
Mountain building
Atmosphere becomes gradually more oxygenated
Diversification of soft-bodied organisms

27. Phanerozoic Eon ~ 542 mya to present
Includes the Paleozoic, Mesozoic and Cenozoic eras
Major mountain-building events
Pangaea continues break up into modern continents
Complex life evolves with much diversification
Geographic separation isolates some populations
Punctuated by mass extinctions
Tiktaalik roseae - a critical transitional organism from Canada’s Arctic

28. In the Paleozoic Era complex life evolved and the continents reorganized

29. The Cambrian Explosion
Organisms that evolved during the Cambrian Explosion, developed some of the basic inherited traits that are still present today, and others that vanished forever.

30. Steven Earle
Steven Earle
Steven Earle
Steven Earle
What is so important about the fossils of the Burgess Shale in the Canadian Rockies?

31. In the Mesozoic Era biological diversity increased and continents reorganized yet again

32. Mesozoic diversity
Plesiosaur
Steven Earle
Allosaurus claw
Dicot leaf

33. The Tethys Sea
Continents separated and moved towards their present configuration. The Tethys Sea (the ancestor to the Pacific Ocean) wrapped the globe along the equator.
Tethys Sea

34. Mammals and birds diversified and primates arose during the Cenozoic Era
Family Hominidae. b d
(a) Sahelanthropus tchadensis (b) Australopithecus afarensis (c) Homo erectus (d) Homo sapiens sapiens

35. Earth in the Quaternary Period
Why was sea level relatively low during much of the Quaternary?

36. COPYRIGHT
Copyright © 2014 John Wiley & Sons Canada, Ltd. All rights reserved. Reproduction or translation of this work beyond that permitted by Access Copyright (The Canadian Copyright Licensing Agency) is unlawful. Requests for further information should be addressed to the Permissions Department, John Wiley & Sons Canada, Ltd. The purchaser may make back-up copies for his or her own use only and not for distribution or resale. The author and the publisher assume no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information contained herein.