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BIO312: Evolutionary Biology

Unit 5: The Fossil Record   Using fossil evidence as well as the physical, chemical and phylogenetic data, scientists have reconstructed history of life on Earth and learned that it extends back many millennia. In this unit, we will learn more about how scientists find and use fossil evidence, as well as how evolutionary changes coincide with geographical changes in the Earth. We will then learn the major species radiations and other occurrences in the evolutionary history, as described on the Geologic Time Scale. 

Unit 5 Time Advisory
Completing this unit should take you approximately 6.5 hours.

☐    Subunit 5.1: 2 hours

☐    Subunit 5.2: 1 hour

☐    Subunit 5.3: 2 hours

☐    Subunit 5.4: 1.5 hours

Unit5 Learning Outcomes
Upon successful completion of this unit, you will be able to: - explain how plate tectonics relates to biogeography; - explain how fossils are formed; - explain how fossils can be used to reconstruct evolutionary history; - explain why microfossils are important to evolutionary history; - list the major events in the history of life on Earth; - define the endosymbiotic theory; - list the ways in which populations can become physically separated; - explain why the Bering Land Bridge is important in biogeography; - explain how the Earth’s climate has changed over geologic time and how it is changing right now due to climate change; - list the Geological Eras and the major events that occurred within each era; and - explain why the Cambrian Explosion is important in the evolution of life on Earth.

  • Lecture: Yale University: Professor Stephen Stearns’s “Major Events in the Geologic Theatre” Link: Yale University: Professor Stephen Stearns’s Major Events in the Geologic Theatre (YouTube)
     
    Also available in:
    [Flash
    Quicktime
    Transcript

    MP3](http://oyc.yale.edu/ecology-and-evolutionary-biology/eeb-122/lecture-18)
     
    Instructions: This video presentation will introduce you to the geologic timeline and cover some of the major events associated with the development of life on Earth. Be sure to take notes and pay particular attention to all the terms the presenter introduces.
     
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5.1 Fossils   5.1.1 Process of Finding   - Web Media: Howard Hughes Medical Institute: Dr. John J Shea’s “Bones, Stones, and Genes: The Origin of Modern Humans” Link: Howard Hughes Medical Institute: Dr. John J Shea’s Bones, Stones, and Genes: The Origin of Modern Humans (HTML)

 Instructions: Watch this video.  

 Watching this video should take approximately 5 minutes.  
    
 Terms of Use: Please respect the copyright and terms of
use displayed on the webpage above.

5.1.2 Obstacles   Note: Despite of the importance of fossils in reconstructing evolutionary history of life, scientists also need many other types of evidence. The fossil record alone poses many obstacles, such as the fact that only some organisms could be preserved in the fossil record, while transitional fossils are missing or incomplete.

5.1.3 Extrapolation from Findings   - Web Media: Howard Hughes Medical Institute “ Fossil Record of Stickleback Evolution” Link: Howard Hughes Medical Institute “Fossil Record of Stickleback Evolution (Flash)
 
Instructions: Watch this video of the evolution of stickleback including findings and interpretation.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Interactive Lab: University of Colorado at Boulder: “Radioactive Dating Game” Link: University of Colorado at Boulder: Radioactive Dating Game (Java)

    Instructions: Follow the instructions to run this simulation. Learn about different types of radiometric dating, such as carbon dating. Understand how decay and half life work to enable radiometric dating. Play a game that tests your ability to match the percentage of the dating element that remains to the age of the object.

    Terms of Use: Please respect the copyright and the terms of use on the webpage above.

  • Web Media: BBC: “Evidence for Evolution—Fossils” Link: BBC: Evidence for Evolution—Fossils (HTML)

    Instruction: Watch the video presented by BBC about a tiny primitive horse.

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5.2 Earliest Evolution   5.2.1 Prokaryotes   - Reading: University of California Paleontology: J.H. Lipps’ “Microfossils” Link: University of California Paleontology: J.H. Lipps’ Microfossils (HTML)
 
Instructions: This webpage includes information about prokaryotes and the early evolution associated with them.
 
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5.2.2 Eukaryotic Cells   5.2.2.1 Endosymbiotic Theory   - Reading: Kimball’s Biology Pages’ “Endosymbiosis and the Origin of Eukaryotes” Link: Kimball’s Biology Pages’ “Endosymbiosis and the Origin of Eukaryotes” (HTML)
 
Instructions: This webpage includes a definition and the history behind Endosymbiotic theory.
 
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5.2.2.2 Earliest Eukaryotes   - Reading: University of California Museum of Paleontology “Introduction to Basal Eukaryotes” Link: University of California Museum of Paleontology Introduction to Basal Eukaryotes (HTML)
 
Instructions: Read this material and be able to identify some of the primitive characteristics that set them apart from prokaryotes.
 
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  • Reading: University of California Museum of Paleontology: Understanding Evolution: “Biogeography: Wallace and Wegener” Link: University of California Museum of Paleontology: Understanding Evolution: Biogeography: Wallace and Wegener” (HTML)
     
    Instructions: This article defines biogeography and relates it to natural selection and the history of evolutionary thought.
     
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  • Assessment: The Saylor Foundation’s “Subunit 5.2.2 Assessment” Link: The Saylor Foundation’s “Subunit 5.2.2 Assessment” (HTML)

    Instructions: Complete this assessment. The correct answers will be displayed when you click Submit. You must be logged into your Saylor account in order to access this exam. If you do not yet have an account, you will be able to create one, free of charge, after clicking the link.
     
    You may retake the quiz as many times as you like to prepare for the final exam. Good luck!

5.3 Biogeography   Note: The abiotic features of an environment have a profound effect on the evolution of the species that live there. Geographical features, for example, affect population migration routes, availability of resources, and ease of access to those resources. Imagine that, over time, a mountain range or large body of water has developed in what was once the continuous range of species. A subpopulation on one side of the environmental feature is now much less likely to interbreed with subpopulation on the other side. Over time, genetic drift alone is likely to cause divergence and perhaps speciation between the subpopulations. On the other hand, development of a land bridge between two isolated territories may create the opposite effect. Changes in geographical features can even cause changes in the climate, as they can affect wind currents and the evaporation-precipitation cycle. Due to these and other climate changes, some species may go extinct, while others may become more competitive, and still others may survive through newly evolved adaptations. In this subunit, we will discuss some specific ways that biogeography can affect evolution.

5.3.1 Plate Tectonics   5.3.1.1 Movement of Continents   - Reading: University of California Museum of Paleontology “The Mechanism” Link: University of California Museum of Paleontology The Mechanism (HTML)
 
Instructions: The website and accompanying links will introduce you to the history and mechanisms of plate tectonics.
 
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5.3.1.2 Development and Removal of Environmental Barriers   5.3.1.2.1 Mountains   - Reading: Wikipedia: “Mountain Formation” Link: Wikipedia: Mountain Formation (HTML)
 
Instructions: The page introduces the link between plate tectonics and mountain formation along with different types of mountains.

 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-ShareAlike
License](http://creativecommons.org/licenses/by-sa/3.0/).

5.3.1.2.2 Waterways   - Reading: MountainNature.com: Ward Cameron’s “A River Runs Through It—River Mechanics” Link: MountainNature.com: Ward Cameron’s A River Runs Through It—River Mechanics (HTML)
 
Instructions: Read this passage for a quick summary of the methods by which waterways are formed and by which water itself affects the surrounding geography.

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5.3.1.2.3 Islands   - Reading: Science Encyclopedia: “Island—How Many Islands?” Link: Science Encyclopedia: Island—How Many Islands? (HTML)
 
Instructions: Read this page which discusses different types of islands and the geology associated with their formation.

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5.3.1.2.4 Land Bridges   - Reading: About.com’s “Bering Land Bridge” Link: About.com’s Bering Land Bridge (HTML)

Instructions: This reading covers the formation, climate, as well
asflora and fauna of the Bering Land Bridge. Bering Bridge is also
as an example of how land bridges form and what biological
consequences such a change might cause.  

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5.3.2 Climate Changes   - Reading: Geocraft.com: “Global Warming: A Chilling Perspective” Link: Geocraft.com: Global Warming: A Chilling Perspective (HTML)
 
Instructions: Read the section on a “Brief history of Ice Ages.” This material covers sections 5.3.2.1 and 5.3.2.2.
 
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  • Reading: Physical Geography.net: M. Pidwirny’s "Earth's Climatic History” Link: Physical Geography.net: M. Pidwirny’s "Earth's Climatic History (HTML)
     
    Instructions: The reading is an introduction to the Earth’s climate history along with methods for reconstructing past climates.
     
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5.3.2.1 Warming Periods   Note: There have been warming periods in geologic history. This is covered in the reading in section 5.3.2.

5.3.2.2 Cooling Periods   Note: There have also been cooling periods in geologic history.This is covered in the reading in section 5.3.2.

5.4 Geologic Time Scale   - Reading: University of California Museum of Paleontology “Geologic Time Overview” Link: University of California Museum of Paleontology Geologic Time Overview (HTML)
 
Instructions: This is an ordered timeline with separate links to all the eons, eras, and periods.
 
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5.4.1 Pre-Cambrian   - Reading: Estrella Mountain Community College: Michael Farabee’s Online Biology Text: “Paleobiology: The Precambrian” Link: Estrella Mountain Community College: Michael Farabee’s Online Biology Text: Paleobiology: The Precambrian (HTML)
 
Instructions: This material covers sections 5.4.1.1 through 5.4.1.2.
 
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5.4.1.1 Archaean   Note: This is covered in the reading in section 5.4.1.

5.4.1.2 Proterozoic   Note: This is covered in the reading in section 5.4.1.

5.4.2 Paleozoic   - Reading: Estrella Mountain Community College: Michael Farabee’s Online Biology Text: “Paleobiology: The Early Paleozoic” Link: Estrella Mountain Community College: Michael Farabee’s Online Biology Text: Paleobiology: The Early Paleozoic (HTML)
 
Instructions: This material covers sections 5.4.2.1 through 5.4.2.3.
 
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  • Reading: Estrella Mountain Community College: Michael Farabee’s Online Biology Text: “Paleobiology: The Late Paleozoic” Link: Estrella Mountain Community College: Michael Farabee’s Online Biology Text: Paleobiology: The Late Paleozoic (HTML)
     
    Instructions: This material covers sections 5.4.2.4 through 5.4.2.6.
     
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5.4.2.1 Cambrian   Note: This subunit is covered by the reading, “Paleobiology: The Early Paleozoic,” assigned beneath subunit 5.4.2.

5.4.2.2 Ordovician   Note: This subunit is covered by the reading, “Paleobiology: The Early Paleozoic,” assigned beneath subunit 5.4.2.