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 million 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 a 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.
Origins of Life
Discover 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.
Rated 4 out of
5
by
Viola from
Interesting but old
I am not sure when this was recorded, but it seems like it is about 15-20 years old! A lot of things have happened during the last two decades.
Date published: 2024-10-29
Rated 5 out of
5
by
misterwhite1 from
Absolutely Brilliant Course
This is easily the most fascinating of the 46 Teaching Company courses that I have bought.
Exceptional presentation; gives shouts out to specific researchers in the field, covers all LEGITIMATE theories, explains the nature of science, discusses the pros and cons of each theory and the path forward with each.
While we MAY never know the exact pathway that life came about on planet Earth, we can see that there are dozens of possible ways life could have started.
We can see from this presentation that the EMERGENCE of life is neither miraculous nor supernatural, but is a natural certainty in this space-time and many other conceivable space-times.
Origins research is one of the most rapidly developing fields of science out there. More has been accomplished since this course was published. It would be terrific if Dr. Hazen were to update his course with the latest developments in the science. I would buy the updated version as well.
Date published: 2023-07-19
Rated 4 out of
5
by
robodoc58 from
Excellent course, but dated
The professor does a very good job of broadly covering the topics from the various disciplines.
BUT! The course was copyrighted in 2005, statements are made looking forward to 2013. It is now 2023. What new data has emerged in 10 years? The Great Courses needs to update this course, or retire and replace it...the same professor would be fine, I suspect (unless he is incapacitated or no longer with us).
I have a few micro-quibbles as well. A number of times the lectures dip down into 10th grade biology. I suspect most viewers are well award of DNA and RNA and don't need a refresher course.
Also, the professor devotes a fair bit of time to the process and politics of scientific publication, at times even sounding whiney that the powers that be did not embrace his presentations. I am all too familiar with the nasty politics of scientific dissemination: the powerful figures protect their domain against those with different ideas. Perhaps lay viewers will benefit from this dirty laundry, perhaps not.
Date published: 2023-03-03
Rated 5 out of
5
by
Gharmjo from
Vastly Superior Evolution Course
Hazen provides detailed recounting of his own and others' attempts to explain how one goes from rocks to humans in a non-magical fashion. His process is to show what was thought historically, discuss clever experiments that elucidate pathways, and end with the ultimate incompleteness of all approaches to date. Spectacular observations include: (L10): "The biggest mysteries (for abiotic synthesis) …are not how to make simple organic molecules but how to select and concentrate just the right ones. The conditions that support synthesis of amino acids are not necessarily the conditions that support…peptide bonds." (L15): "The great mystery…lies in the gap between simple organic molecules and primitive cells." "The idealized picture of an unbroken branching history of DNA evolution from parent to daughter is invalid." There are "countless perplexing cross-links and no one 'last common ancestor' ". The L17 clay life hypothesis and Cairns-Smith's genetic takeover of clay layer sequencing is stunning but tenuous because "No technology exists to sequence clays". The chapter ends on the "magic" of clay powder on nucleotide and lipid experiments.
A L23 example demonstrates why humility regarding evolution is paramount: "Perhaps for HUNDREDS OF MILLIONS OF YEARS (caps mine), there was a kind of stable state" where "new supplies of each molecular species balanced the losses…but the system doesn't …change with time." Yet L5 stated that life itself (not just molecular equilibrium) began somewhere between 150 TO 500 MILLION YEARS (caps mine) after the inhospitable Hadean. That leaves potentially no time for evolution from a geochemical world to a living world. On top of this, transitioning "…from a geochemical world to an evolving biochemical world…" has no accepted evolutionary proof. L24 presents today's 3 best life theories and their problems: 1.) A self-replicating chemical cycle (perhaps the reverse citric acid cycle) on a mineral surface - though no one has shown how that path can synthesize a key element (4-carbon oxaloacetate); 2.) A self-replicating RNA strand via a clay mineral template or RNA/DNA mimicry based on PAH (polycyclic aromatic hydrocarbon) as suggested by the Martian meteorite cyclic molecules (L5) - has not been produced in any lab (L22); 3.) A metabolic/genetic cooperative chemistry - yet genetic molecules are too unstable and nucleotides are not found in the primordial soup.
This 2005 course is enormously helpful for anyone who has difficulty with the blithe "millions of years" excuses often used to justify an evolutionary POV. Hazen begins with early academic ideas that were accepted simply because the truth of Darwinian observations was used as a veil to cover the enormous complexities of the process. Hazen's (L24) conclusion: "A central theme of this…series is the remarkable power of emergence to drive increases in the complexity of natural systems. The theory of emergence argues for inexorable evolution of the cosmos, from atoms to stars to life." That is to say: emergence was BUILT INTO THE UNIVERSE and preceded Darwinism. Reviewers on either side of the Intelligence vs lucky evolution question must be treated respectfully. However, L1 cautions the "lucky" adherents: "It is possible that life emerged by an almost infinitely improbable sequence of difficult chemical reactions." L19 adds that Sydney Fox's first comprehensive origin model of "metabolism before genetics" suggested that life's origin processes might be non-random and deterministic. Numerous origins workers now accept this. If you have taken The Great Course "Chaos" by Strogatz, you will understand Hazen's brilliant L5 sentence: "All of these observations suggest a mathematical relationship between the concentration of agents…and complexity." L8 then describes these math burdens on the "millions of years" veil via the four factors that "contribute to the emergence of complexity: 1.) The math of interacting particle concentration is complexly nonlinear and reaches what other courses call the "Turing Instability" where patterns suddenly emerge; 2.) Emergent complexity is fostered by agent interconnectivity; 3.) Emergent complexity energy flux hits a certain pattern formation criticality but would cause randomized entropy at higher levels; 4.) Energy flux must be altered by subtle, difficult to recognize cycles. Evolution is nonlinearly complex; there is much we simply don't/can't know.
CONCLUSION: The beauty of all of this is Hazen's huge effort to accurately portray what is known about both molecular stability states AND primitive reproductive evolution – even as current origins explanations look inconclusive. Although more has been discovered since 2005, this course's major conclusions remain unchallenged.
Date published: 2022-07-01
Rated 5 out of
5
by
awol from
A once in a lifetime insight into a scientific research process. The subject is a profound story of "Emergence", comparabe to the Universe or Consciousness. A rare (only?) truely-mulitidisciplined collaboration of both theoretical concepts and the analysis of experimentation result. A Great Course by a great lecturer.
Date published: 2022-03-18
Rated 2 out of
5
by
DebRog from
Disappointed course
The title indicates that I might learn the the origins of life, but, in the first lecture, he states this is unknown. The lecturer just reads from a teleprompter or paper. He doesn’t really seem to know his subject since he just reads….no eye contact at all with audience.
Date published: 2022-01-31
Rated 5 out of
5
by
Sosigenes from
An excellent presentation
This is a difficult subject for a lecturer to present, because it is necessarily of a significantly speculative nature. However, this is how new science develops into an eventually rigorous discipline. Thank you Prof. Hazen.
Date published: 2022-01-23
Rated 5 out of
5
by
Multiverse Jim from
Well done coverage of every cientific aspect
I still have 3 lectures left, but the lectures have filled in several holes in my knowledge of this topic and explained many of the problems, solutions and alternative theories. Excellent course.
Date published: 2021-10-01
Overview
About
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 Cambridge University in England before joining the Carnegie Institution. At Carnegie, Dr. Hazen's research focuses on high-pressure organic synthesis and the origin of life.
Professor Hazen has authored 15 books, including the best-selling Science Matters: Achieving Scientific Literacy and The Sciences: An Integrated Approach. He has written over 220 articles for both scholarly and popular publications such as Newsweek, Scientific American, The New York Times Magazine, Technology Review, and Smithsonian Magazine.
He has received the Mineralogical Society of America Award, the American Chemical Society Ipatieff Prize, the Educational Press Association Award, the American Crystallographic Association's Science Writing Award, and Fellowship in the American Association for the Advancement of Science.
Professor Hazen serves on the advisory boards for The National Committee for Science Education, Encyclopedia Americana, NOVA, and the Carnegie Council. He appears frequently on radio and television programs on science.
01: 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.
30 min
02: 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).
31 min
03: 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.
31 min
04: 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.
31 min
05: 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.
31 min
06: 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.
30 min
07: 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.
31 min
08: Emergence
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.
30 min
09: 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.
31 min
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.
30 min
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.
31 min
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.
30 min
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.
32 min
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.
30 min
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.
30 min
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.
30 min
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.
32 min
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.
32 min
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.
31 min
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.
31 min
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.
31 min
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?
30 min
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.
31 min
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.
31 min
