Origins of Life

Course No. 1515
Professor Robert M. Hazen, Ph.D.
George Mason University
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Course No. 1515
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Course Overview

Four billion years ago, the infant Earth was a seething cauldron of erupting volcanoes, raining meteors, and hot noxious gases, totally devoid of life. But a relatively short time later—100 to 200 million years—the planet was teeming with primitive organisms. What happened?

Professor Robert M. Hazen, one of the nation's foremost science educators and leader of a NASA-supported team that is studying the origins of life in the universe, leads you on a 24-lecture expedition to find the answer to this momentous question.

The search takes you from path-breaking experiments in the 19th century proving that the molecules of life are no different from other chemicals, to the increasingly sophisticated understanding in the 20th century of how the chemistry of life works, to the near certainty that the 21st century will see spectacular and unpredictable developments in our understanding of how life began.

From Simple Chemistry to DNA

For all its familiarity, life is an elusive concept that is hard to define, much less explain. This course shows how scientists are systematically building a picture of the process by which chemical reactions on the early Earth eventually led to the first appearance of the DNA-protein world that remains the fundamental basis of all life today.

Dr. Hazen's own work makes him the perfect guide to present key ideas and controversies in this research, and to introduce you to the most important scientists working in the field—many of whom he knows personally. Under his guidance, you will join researchers as they seek to establish the earliest appearance of life on Earth, as they grapple to explain how it arose, and as they probe for evidence of life beyond our planet.

Dr. Hazen is a superb science teacher, whose previous course for The Teaching Company, The Joy of Science, earned this accolade in AudioFile magazine: "From the very beginning, one recognizes the gift of Professor Hazenàto make science easy to understand."

This course is crammed with fascinating experiments, surprising results, heated debates, blind alleys, and promising leads. It is a mystery story in the truest sense—one in which the clues are slowly adding up but the solution is not yet in hand.

Not Your Usual Science Course

The Origins of Life introduces you to a scientific problem that is far from solved but one which is all the more thrilling for that reason. "The most exciting aspect of science is the process of discovery," says Dr. Hazen. "The origin of life is a perfect subject to reveal that ongoing adventure that is the very essence of science."

This is not your usual science course, which traditionally presents a consensus view on known facts about the world. Instead, Professor Hazen plunges into the thick of ongoing research. "I want to take you into the field to see what the geologists see, and to puzzle with them as they try to sort out the meanings of ancient rocks. I want to take you into the laboratory and show you how we do origin experiments. I want you to see how unscripted and creative the scientific process really is. I want you to get a sense of how scientists around the world are trying to fill in the blanks of our ignorance."

"We are in the midst of a remarkably dynamic stage of research into the origin of life," he continues. "I've never seen a scientific field with so many wild new ideas."

Intriguing Theories

What are some of these ideas?

  • Life from the Bottom of the Sea: The discovery in the 1970s of flourishing communities of microbes around hydrothermal vents at the bottom of the sea raises a fascinating possibility. Perhaps life formed in the ocean depths, far from the sunlight that nourishes life today, but protected from the withering rain of comets and meteorites that pummeled the surface of the early Earth.
  • Life from Deep in the Earth's Crust: Drilling studies show that microbes live in every possible subterranean environment—from buried desert sands, to mile-deep Antarctic ice, to pristine rock in the bowels of gold mines. Could the story of life have started underground, where water and chemically unstable rocks provided the chemical energy to power the emergence of life?
  • The Ocean Spray Model: Four billion years ago, naturally occurring organic molecules accumulated at the ocean's surface like an oil slick. The turbulence of whitecaps and crashing waves produced a continuous fine mist in which organic molecules may have reacted with water and air to produce cell-like structures that were the precursors to life.
  • Clay as Life: Fine-grained crystals of clay might, all by themselves, have been the very first life forms on Earth. According to this hypothesis, self-replicating clay crystals evolved the ability to manufacture complex biomolecules such as RNA, which eventually out-competed their clay cousins to become the dominant form of life on the planet.
  • Flat Life: In this scenario the very first self-replicating entity was a thin layer of chemical reactants that grew on mineral surfaces. This flat life spread from mineral grain to mineral grain as a coating of organic molecules too thin to see. Extensive colonies of flat life might survive even today in deeper parts of the Earth's crust.

You will also learn about classic experiments that were wild ideas in their own time, such as Louis Pasteur's demonstration in the mid-1800s that life does not spread by spontaneous generation, as was widely believed. By proving that no cellular life can occur without prior cellular life, his findings pushed back life's origins to an almost inconceivably remote time and place.

Another breakthrough occurred in 1953, when Stanley Miller showed that a flask containing a mixture of the conjectured gases in Earth's early atmosphere yielded a rich assortment of complex organic molecules when lightning-like sparks were introduced. This simple experiment confirmed an idea of Miller's mentor, Harold Urey, and was the first demonstration of a plausible life-forming process.

Inside Science

One of the most intriguing features of this course is that Dr. Hazen gives you an inside picture of how science works, relating several enthralling discoveries in his own research and that of his colleagues, including:

  • The Case of the Martian Meteorite: In 1996, NASA announced the discovery of fossil life forms in a meteorite known to be from Mars. Professor Hazen describes the exhaustive battery of tests that supported the claim. He also recounts the detailed counter-arguments marshaled by skeptical scientists.
  • The Controversy over Earth's Oldest Fossil: In 1993, paleontologist J. William Schopf reported the discovery of fossilized single cells preserved in a 3.5-billion-year-old rock from Australia—the oldest fossils ever found. Professor Hazen describes the heated scientific controversy that later erupted over the claim.
  • The Mystery of the Bourbon-Scented Reaction: In 1996, Professor Hazen and biologist Harold Morowitz collaborated on an experiment to investigate chemical reactions under extremely high pressures such as those that may have led to the origin of life deep underground. The unexpected result was a rich mixture of organic molecules that "smelled a lot like Jack Daniels!"

As you listen to this course, you will be amazed, enlightened, tantalized, and sometimes baffled. "But by the time you're through with this lecture series," promises Dr. Hazen, "you'll be poised to share in all the incredible discoveries that are about to come. And I absolutely guarantee there will be exciting discoveries in the quest for life's origin."

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24 lectures
 |  Average 30 minutes each
  • 1
    The Grand Question of Life’s Origins
    Professor Robert M. Hazen introduces the mystery of life's origins and outlines three reasons why this is "not your usual science course:" (1) the answer to the problem is not yet known; (2) the course emphasizes the process of science; (3) the search for life's origins is controversial in a way that other scientific studies are not. x
  • 2
    The Historical Setting of Origins Research
    This lecture reviews the history of origins research and shows how early efforts to answer this question were hampered by the absence of: relevant evidence, appropriate experimental equipment, and a theoretical understanding of emergence (the spontaneous origin of complexity out of simple systems). x
  • 3
    What Is Life?
    Life probably arose as a sequence of steps. First came the synthesis of simple organic molecules. Next came the assembly of macromolecules. Eventually, an evolving, self-replicating collection of macromolecules emerged. Each of these stages added some degree of chemical and structural complexity. x
  • 4
    Is There Life on Mars?
    You survey the quest for life on Mars from the telescopic era to the space age. While studies by spacecraft on Mars have given ambiguous results, another source of data is from meteorites that are known to have come from Mars; one of these is the subject of a controversial claim for evidence of life. x
  • 5
    Earth’s Oldest Fossils
    You continue your study of life's origins in the "top-down" approach, which works backward from known life forms toward a hypothetical common ancestor. This lecture focuses on rocks found in Australia that may contain fossilized cells that are the oldest record of living organisms on our planet. x
  • 6
    Fossil Isotopes
    Occasionally a dying organism is entombed in rock that is impermeable, allowing the original atoms and molecules of that organism to persist for hundreds of millions of years. Professor Hazen follows research on such samples, which provide intriguing evidence of early life. x
  • 7
    Molecular Biosignatures
    Even when evidence such as bones or shells is lacking, fossil elements, isotopes, and biosignature molecules point to the nature of primitive biochemical processes and give scientists their best hope for narrowing the time window for life's emergence. x
  • 8
    You turn to the "bottom-up" approach to life's origins, which starts with conditions on the primitive Earth and attempts to work out the chemical steps that must have occurred for life to arise. Crucial to this process is the new and exciting field of emergence, which this lecture explores in detail. x
  • 9
    The Miller-Urey Experiment
    In 1953, the landscape of research on the origins of life changed forever with the Miller-Urey experiment. For the first time, an experimental protocol mimicked plausible life-forming processes. As you'll see, the emergence of simple biomolecules is arguably the best understood aspect of the origins of life. x
  • 10
    Life from the Bottom of the Sea
    By the late 1970s, enough problems and questions had been raised about the Miller-Urey experiment that alternative hypotheses were proposed. One of the first and most influential of these competing models was the idea that life might have arisen in the deep ocean at a hot hydrothermal vent. x
  • 11
    The Deep, Hot Biosphere
    The hydrothermal-origins hypothesis prompted scientists to look for life in deep, warm, wet environments. And everywhere they looked—in deeply buried sediments, in oil wells, even in volcanic rocks more than a mile down—they found abundant microbes. You review the implications of these extraordinary discoveries. x
  • 12
    Experiments at High Pressure
    In order to explore the deep-origin hypothesis, scientists need a new breed of experiments. Professor Hazen gives a fascinating account of one of the first high-pressure experiments to test this theory, which took place in his own laboratory at the Carnegie Institution of Washington. x
  • 13
    More Experiments Under Pressure
    In this lecture you investigate some of the many possible directions of research to understand the possibility of life under hydrothermal conditions of high pressure. Such experiments are expensive, and Professor Hazen begins his remarks by discussing how origins research is funded. x
  • 14
    Deep Space Dust, Molten Rock, and Zeolite
    The last place you might think to look for life-forming molecules is the black vacuum of interstellar space. But new research is revealing that deep space is loaded with interesting organic molecules. You also explore two other surprisingly productive environments: igneous rocks and zeolite crystals. x
  • 15
    Macromolecules and the Tree of Life
    In this lecture Professor Hazen begins his study of the second great emergent step in the path from geochemistry to biochemistry: the emergence of macromolecules. Efforts to map the tree of life suggest that early life may have used a more diverse set of organic molecules than life does today. x
  • 16
    Lipids and Membrane Self-Organization
    Life had to develop some kind of protective membrane that isn't soluble in water. You explore two possible solutions to this problem, both of which involve fatty molecules called lipids. The amazing ability of lipids to self-organize was probably an essential step in the emergence of life. x
  • 17
    Life on Clay, Clay as Life
    The best way to assemble life's molecules in water is to "call in the rocks." In this lecture, you look at some of the ways that minerals might have played a role in selecting and organizing biomolecules. In particular, you focus on the ubiquitous group of minerals called clays. x
  • 18
    Life’s Curious Handedness
    This lecture explores an alternative approach to the selection and concentration of organic molecules that exploits the property of "handedness." Many molecules come in mirror-image pairs, like a left and right hand, and the processes of life prefer one "hand" over another. x
  • 19
    Self-Replicating Molecular Systems
    In the first of two lectures on self-replicating molecular systems, Professor Hazen shows that such systems are not necessarily alive, but they do have something like metabolism. The emergence of metabolism is a giant step toward understanding the origins of life. x
  • 20
    Günter Wächtershäuser’s Grand Hypothesis
    Which came first, metabolism or genetics? This may be the most fundamental scientific debate related to the origins of life. You examine views on each side of this question and focus on the most elaborate and comprehensive theory of metabolism-first—the iron-sulfur world of Günter Wächtershäuser. x
  • 21
    The RNA World
    Exploring the idea that life began with genetics, you study the RNA World scenario, which holds that the first life form was a self-replicating strand of RNA. There is abundant evidence that RNA is a truly ancient molecule that can fulfill the essential prebiotic chemical roles. x
  • 22
    The Pre-RNA World
    Before scientists can fully understand the origin of the RNA World, they must focus on what came before. By what chemical process did the first self-replicating, information-bearing system emerge? And if it wasn't RNA, then what was it? x
  • 23
    Natural Selection and Competition
    So far, one critical step in the transition from non-life to life has been left out—evolution. Competition helps drive evolution, and in this lecture you see how the struggle for resources among living chemical systems can lead to rapid evolution by natural selection. x
  • 24
    Three Scenarios for the Origin of Life
    Professor Hazen summarizes the course by reviewing three plausible scenarios for the origins of life: (1) life began with metabolism; (2) life began with a self-replicating strand of some genetic molecule; (3) life began as a cooperative chemical phenomenon, arising between metabolism and genetics. x

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  • Download 24 audio lectures to your computer or mobile app
  • Downloadable PDF of the course guidebook
  • FREE audio streaming of the course from our website and mobile apps
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DVD Includes:
  • 24 lectures on 4 DVDs
  • 202-page printed course guidebook
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What Does The Course Guidebook Include?

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  • 202-page printed course guidebook
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  • Suggested readings
  • Questions to consider

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Your professor

Robert M. Hazen

About Your Professor

Robert M. Hazen, Ph.D.
George Mason University
Dr. Robert M. Hazen is Clarence J. Robinson Professor of Earth Sciences at George Mason University in Fairfax, VA, and a research scientist at the Geophysical Laboratory of the Carnegie Institution of Washington. Professor Hazen earned his bachelor’s and master’s degrees in geology from the Massachusetts Institute of Technology. He earned a Ph.D. in Earth Science from Harvard University and did post-doctoral work at...
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Origins of Life is rated 4.4 out of 5 by 82.
Rated 5 out of 5 by from Great Course for the Great Courses I really enjoyed this course and its interdisciplinary approach. It showed how many different scientific fields need to collaborate in order to find the truth about life's origins in the primordial world. Thanks for a great course!
Date published: 2020-10-29
Rated 5 out of 5 by from Most illuminating and well delivered I must say, that when I bought this course, I had no idea how interesting it would be. Initially, it took me a little time to get used to the style of presentation, but boy was the course good. It is an unbiased account of all the probabilities that got life going on this planet. The various options molecular, thermal and genetic are all discussed; never mind that we do not have a conclusion yet but the lecutures provoke thinking. May be in the future some wise person will find a solution or prehaps not. The journey was enjoyable. Thank you Professor Hazen
Date published: 2020-08-28
Rated 4 out of 5 by from Achieved Expectations I bought this course because I wanted to get an overview of the foundational thoughts concerning the "Origins of Life". The course achieved this expectation. The information concerning organic and biochemistry were deftly presented, in that the role of the chemistry, re the origins of life, were discussed without undue emphasis on the chemical details. The lecture on Lipids was particularly fascinating. This is not a course on organic chemistry, so if the student gets lost in the details, I think the student is trying to delve too deeply into the chemical processes. I thought the balance between concept and detail was about right. I thought Dr Hazen did an excellent job of presenting the historical ups and downs of doing research into the origins of life research area. The course is a good example of how scientific research actually proceeds in the laboratory as well as the human interactions involved. I enjoyed all the historical context. Dr Hazen's real life examples were well taken. Although I feel I got a good grounding in the state of this science, I feel it is probably about time to come out with an update, since the results are well over a decade old. I felt Dr Hazen was clear and concise in his presentations, but needs to polish up his presentation in front of a camera. I felt he was never talking to me or to a class and acted rather robotically. For me, the course was well worth the cost.
Date published: 2020-07-27
Rated 5 out of 5 by from Complicated, but fascinating! The lecturer shows HOW DIFFICULT is is to determine just how life started, and when. But at least he defines what we call "life", as something which can grow; multiply. and evolve. Your computer can't do that, but your grass and trees and you can do that!
Date published: 2020-05-15
Rated 5 out of 5 by from origins off life I've owned this course for at least 10 years in audio. It is wonderful and I've gone over parts of out many times. However it is now dated and it would be great if you could get Hazen to update it. Many discoveries have occurred and I'm sure he would be happy to add some finishing touches. If you do, I'd buy it in video
Date published: 2020-04-29
Rated 4 out of 5 by from mixed reaction very good professor; very interesting subject. But unless you have a solid (better yet, an advanced) knowledge of chemistry, the presentation is often very difficult to absorb. my rating it "no" as to recommending it & its value, are based on the assumption of not having such strength in chemistry.
Date published: 2020-02-06
Rated 5 out of 5 by from State of the field The course obviously is not going to present you with the answer to the origin of life on earth, since this is an ongoing field. Rather it talks about a great variety of approaches to the issue and ideas that have been investigated. These include organisms that might have originated deep in the sea in hot vents. There is also discussion of exactly how you define life.
Date published: 2019-12-05
Rated 5 out of 5 by from Good ideas trigger crucial experiments An excellent course full of great ideas to lead crucial experiments to reveal the secrets of the origins of life (if not now they will be possible in the future). I enjoyed very much the eloquent and didactic teacher’s style.
Date published: 2019-11-05
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