The Origin and History of Life on Earth

Lynn S. Fichter -
James Madison University; 233 Miller Hall - phone 6531
Course Schedule
Text Books
Part One
Part Two
Part Three
Final Exam
Catalog Description
The history of non-vertebrate life from its origin, through evolving biogeochemical cycles, origin of eukaryotes and multicellularity; evolutionary records of all major groups and theoretical issues such as major group origins, adaptive radiation patterns, extinctions, functional adaptations, and paleoecology. 4 credits (3, 2)
Office Hours
Monday and Wednesday 10-11; T/T 8-10; By appointment; or anytime I am in my office, which is most of the time, and not immediately tied up with something else. Just come by, or call to see if I am available.
Final Exam Time
What the Course is About

Read the average biology textbook and you might think that we understand the nature of life and how it evolved. Nothing could be farther from the truth. Every theory concerning the origin and history of life is rife with controversy. Deep differences of opinion exist over the tempo of evolutionary change (gradual vs. punctuational), the motor of organic change (internal vs. environmental), and the direction of evolution (directional and progressive vs. steady state - life as a random walk). What is more these different readings of the record of life have existed ever since Darwin's time.

Trying to understand life solely from the study of living organisms is like trying to understand a 2 hour movie by just watching the last 5 minutes. You may learn the final outcome, but not how or why, and you would miss all the interesting things that have happened along the way. For the truth is, much of the mystery of life is still a mystery, buried in the 3.6-3.8 billion year history of life.

There are, however, things we do know about the history of life and the earth.
  • Life on Earth at this moment is vastly more complex than most of us realize, yet ninety-nine percent, probably more, of the species that have lived on this planet are extinct.
  • The most abundant and most important life forms throughout earth history have been bacteria. They invented all the important biochemical pathways, created the first oxygen atmosphere, and are responsible for the most important biogeochemical links.

  • Multicellular life has existed on earth for only about 15 percent of its age.
  • Yet virtually none of the multicellular phyla have gone extinct.
  • While at the same time most of us would find almost nothing familiar about marine life 500 million years ago.

  • Without life the Earth today would be without significant water, would have an atmosphere of about 95% carbon dioxide, and an average temperature closer to 200 degrees rather than the present 55 degrees - a thermodynamically closed and dead planet more akin to Mars than the Earth today.
  • Yet, in the past 3.5 billion years the earth and life have experienced several environmental crises more severe than anything we consider an environmental crisis today, crises that have reset the evolutionary clock and sent life off in entirely new directions.

The paleontological study of life is not simply about the past it is also about change and continuity. Most of all it is about the long run. Earth environments and life's relationship to those environments cannot be understood in isolation. Environmental conditions that exist today are embedded in and reflect processes that can only be understood at time spans extending far beyond the short window of human experience, far beyond experiments run under controlled laboratory conditions and for time spans that are geologically instantaneous.

The study of paleontology tells us that life processes in a geological context are historical events; their magnitude, structure, cause, and consequences have been highly variable. Furthermore, these variations are patterned in ways we are only beginning to understand, and that cannot be understood only from study of the present. Life can be understood only in terms of the earth system as a whole traced through it 4 billion years of dynamic change.

Finally, unraveling the history of life requires many lines of evidence, biological, geological, paleontological, biochemical, and biogeochemical. This course applies all these lines of evidence to understand not only life itself, but also the scientific controversies that surround our study of it.

Part One - Theoretical Foundations,
Through Evolutionary Principles
and the Gaia Hypothesis
Test Questions
Supporting Pages
   Test Instructions - All lecture tests have two parts, an objective, computer graded part, and an essay part. The rules and guidelines are here. They apply to all tests.
    The essay questions you have ahead of time to prepare for and are linked individually below. I will add them one by one as we cover the material.

   Sample Objective Test - I do not have a previous test from this class to show you. However, the sample test from another class covers, in part, the same material, and is the format I will use for the test.
Essay Questions - pdf files
  #1 - Non-Equilibrium Thermodynamic Principles
  #2 - Chaos and Complexity Theories
  #3 - Artificial Life and Cellular Automata
  #4 - Applying Chaos and Complexity Theory To Evolution
  #5 - The Gaia Theory and Daisyworld Models
New Illustrations Not In Notebook
   Venus, Earth, Mars
   Earth Without Life

Selected Lecture Notes - pdf files    Information flow in Turnover Pulse Hyp
   A Parable of Interdependence - 2 p
Other Links From/For Lecture    Lynn Margulis & Dorian Sagan - Links to some of the contributions these two have made:
   Chaos/Complexity Computer Programs - We used a number of programs to illustrate chaos principles. All these programs are available in the Geology Computer Lab, Miller 224. In addition to homework, you are also welcome to just play with the programs; some are really neat. Above link introduces programs and troubleshoots.
   Gaia Hypothesis - page of links

Part Two - Origin of Life,
Through Archean and
Proterozoic Ecosystems
and the Protist Fossil Record
Test Questions Preparing For the Exams    The second exam follows the same rules and procedures as the first exam. Refer to Exam Number One OR Test Instructions for a discussion of those rules and procedures.
   One reminder. Some of the questions below are minimally stated. You are expected to fill out the details and tender a well rounded, complete exploration of the subject at hand, as we did in class, supplemented by any readings associated with the subject.
  #1 - Biases and Assumptions of the Origin of Life
  #2 - Archean Evolution and Ecosystems
  #3 - Proterozoic Evolution and Ecosystems
  #4 - Archean and Proterozoic Daisyworlds
  #5 - The Ecology and Geological Record of Stromatolites and Benthic Protoctists
  #6 - The Ecology and Geological Record of Pelagic Protoctists
New Illustrations
  Archaean Gaia Diagram - pdf color version
  Biogeochemistry diagrams - pdf color version
  Pelagic Ocean Deposits - pdf
Selected Lecture Notes - pdf files
   Origins of Life - 29 p
   Archaean-Proterozoic Transition - pdf

Other Links From/For Lecture
  Thermal Vents - links for homework problem.
  Extremophiles - links for homework problem.

Note that the last test is the final exam and it is not comprehensive.
Just work from the questions provided. Last time the course was taught
there were only 3 tests, but we will see how it goes.
Part Three - Phanerozoic Record of Life,
Origin of Multicellularity,
Origin, Significance, and Function of the Coelom and Skeleton,
Through Coelomic Adaptive Strategies
Test Questions
Selected Lecture Notes - pdf files
Other Links From/For Lecture

Lab Stuff
   This table captures anything that applies to the laboratory. It is a random assortment of odds and ends.

   Cephalopod Charts and Diagrams.