Open Questions: Origins of Life
See also: Molecular biology and genetics --
Problems about "origins" are always difficult ones in science, for a variety
Origin events tend to be unique. We can't usually observe them
repeatedly. In fact, if the event happened only once, in the distant past,
there were not even human observers at the time. Sometimes there is
at least evidence of the event that we can observe and study, but sometimes
there isn't even that -- especially in the case of the origins of life.
And of course, we are usually in even less of a position to perform
realistic experiments on origin events to test hypotheses. Sometimes
we can perform simulations, either physically or with the assistance of
computers, but these have to be based on guesses about the relevant
conditions. And even if the simulation has positive results, it can only
tell us how the origin event might have happened.
As noted, as far as the origins of life are concerned, we have very little
physical evidence to go on. And we can only make guesses about what
conditions on Earth were like when life first appeared.
We know more about the origins of the universe itself. We can actually
"see" (with suitable instruments) what the universe looked like at an
age of about 300,000 years -- in the form of the cosmic microwave
background. Our vision of what the Earth was like at a similar age is
much less clear. We also have physical evidence of what the universe
was like when it was only minutes old, in the form of the relative
abundances of a few light elements. All the deuterium that exists
today was created at that time and is tangible evidence of prevailing
conditions. We even have reliable physical theories (the "standard model"
of particle physics) which allows us to infer what the universe was like
when it was only a small fraction of a second old.
We have none of this, neither good evidence nor theory, to deduce what
conditions on Earth were like when life appeared.
Hence it's quite likely that this origin question isn't going to be
settled in the near future.
Sites with general resources
Energy Flow and the Organization of Life
- This is a working paper by Harold Morowitz and D. Eric Smith
supporting their hypothesis that the appearance of life on
any sunny, wet, rocky planet is almost a physical necessity.
"Life is universally understood to require a source of free
energy and mechanisms with which to harness it. Remarkably,
the converse may also be true: the continuous generation of
sources of free energy by abiotic processes may have forced
life into existence as a means to alleviate the buildup of
free energy stresses."
The Geochemical Origins of Life
- The site presents the theories of Michael J. Russel and
Allan J. Hall on the origins of life. They believe that
"a major geological process, the cooling by seawater of rocks
under the floor of the ocean, played an important role in the
origin of life."
A statement of their theory is
here, and a summary of non-specialists is
- Home page of research group led by Pier Luigi Luisi.
"There are two main research areas in the group: one is the
self-assembly and self-organization of macromolecular surfactant
aggregates (in particular lipids) and the relevance of these
assemblies - micelles, vesicles and liposomes - as models for
biological membranes and cells, while the other focuses on
polypeptides and the question as to the origin of their structural
order, in particular the origin of their homochirality and of their
primary sequences and folding."
research page provides more information about current
Stephen J. Mojzsis
- Personal page of researcher involved in discovery of ancient
carbonaceous material in Greenland. Contains links to relevant
publications in PDF format. Another version of the page is
Gustaf Arrhenius' Home Page
- Arrhenius' research focuses on reconstructing
"possible pathways toward life on Earth by model experiments, which
are guided by geophysical and geochemical constraints".
Includes abstracts of recent publications.
Surveys, overviews, tutorials
Origin of life
- Article from
RNA world hypothesis,
Was our oldest ancestor a proton-powered rock?
- October 2009 New Scientist article.
"Peter Mitchell was an eccentric figure. For much of his career
he worked in his own lab in a restored manor house in Cornwall
in the UK, his research funded in part by a herd of dairy cows.
His ideas about the most basic process of life - how it gets
energy - seemed ridiculous to his fellow biologists."
The Extraordinary Ecosystems of Enceladus
- April 2008 article from NASA's
Astrobiology Magazine, by
Chris McKay and Dennis Matson. Discusses three type of terrestrial
extremeophiles and the implications for the origins of life and
the possibility of life on Enceladus.
When did life begin?
- September 2009 article. "Biological curves were used to
date the earliest forms of life. But could the discovery of
how to make curved inorganic materials in the laboratory throw
our understanding of life on Earth?"
Astrobiology and the Origins of Life
- Very good overview lecture by Stanley Awramik, at the
The emphasis is really on the origins of life on Earth, rather than
astrobiology in general.
Evolution and diversity of cells
- Some brief notes about issues related to the origins of life.
Catastrophe, Mother of Evolution: Life Survived Early Bombardment
- December 2000
article from Space.com.
Discusses recent evidence of biological activity in rocks 3.85 billion
Greenland Rocks Tell New Tale of Life on Earth
- March 1997 article from NSF
Frontiers about the discovery of life-related carbonaceous
material in 3.85 Ga rocks from Akilia Island in Greenland.
Life on Earth began at least 3.85 billion years ago
- NASA press release on the Akilia Island carbonaceous material
Isua Multidisciplinary Research Project - Description
- Background information on the Isua Greenstone Belt of Greenland,
in which evidence of ancient carbonaceous material has been found.
Evidence for Life on Earth More Than 3850 Million Years Ago
- Article on ancient carbonaceous material in Greenland, by
Heinrich D. Holland
Vestiges of a Beginning: Clues to the Emergent Biosphere Recorded
in the Oldest Known Sedimentary Rocks
- Very informative April 2000 article by Stephen J. Mojzsis and
T. Mark Harrison on earliest chemical evidence of life.
Evidence for Earliest Known Life on Earth
- Brief page about the Greenland rock containing eividence of
Pursuing Life on Two Frontiers
- November 9, 1996 article from Science News on Greenland
evidence of ancient life.
- Very informational
article by Catherine Zandonella on the chemistry of the first
RNA world gets support as prelife scenario
- April 2001 news article from
Science News, about
a modified form of RNA that can perform functions that normally
require the help of proteins.
Cooking up a key chemical of life
- September 2000 news article from
Science News, about
experiments that produced pyruvic acid under conditions similar
to those existing in ocean floor hydrothermal vents.
Using Math to Explain How Life on Earth Began
- October 2008 Scientific American article, subtitled
"How did self-replicating molecules come to dominate the early
Earth? Using the mathematics of evolutionary dynamics, Martin
A. Nowak can explain the change from no life to life."
Scientists Repeat Evolution's Most Famous Experiment
- March 2007 Scientific American article about a repeat
of the Miller-Urey experiment, in which amino acids were found
after steps were taken to prevent
destruction of amino acids by nitrites and acids.
A Simpler Origin for Life
- February 2007 Scientific American In Focus article,
subtitled "The sudden appearance of a large self-copying
molecule such as RNA was exceedingly improbable. Energy-driven
networks of small molecules afford better odds as the initiators
A Precursor of RNA?
- November 2000 Scientific American news article, about
the chemical synthesis of a molecule that may have been a
precursor to RNA.
The Raw Materials
- March 1999 Scientific American Explore article, subtitled
"The chemistry of life is an integral part of the process that
births stars." About the interstellar formation of organic
Life, Life Everywhere
- November 1996 Scientific American Explore article,
subtitled "The origin of life on earth appears more and more
inevitable--or does it?."
Origins of Life
- Very brief overview of a few aspects of how life may have
Life from scratch
Science News, July 3, 2010
- Relaunching biology from the beginning.
The Origin of Life
James Trefil; Harold Morowitz; Eric Smith
American Scientist, May-June 2009
Are Aliens Among Us?
Scientific American, December 2007
- It Came from Outer Space
Astronomy, November 2002, pp. 36-41
- Evidence from radio astronomy and the study of a few meteorites
which contain a diversity of organic compounds suggests that these
compounds are routinely synthesized in interstellar space. Arriving
on Earth in grains of dust, they may have provided the raw materials
for life here and elsewhere.
- An Argument for the Cometary Origin of the Biosphere
Armand H. Delsemme
American Scientist, September-October 2001, pp. 432-442
- Evidence increasingly suggests that comets brought much of
Earth's atmosphere and water, as well as organic molecules,
during the first 600 million years after the planet formed.
This would have provided the raw materials for the origins of life.
[Abstract and references]
- Life's Rocky Start
Robert M. Hazen
Scientific American, April 2001, pp. 76-85
- Life on Earth must have originated as a chemical event.
Crystalline surfaces of certain minerals may have provided a
scaffolding for the construction of biological molecules.
Cosmic Chemistry Gets Creative
Science News, May 19, 2001, pp. 317-319
- All the chemical compounds necessary for life seem to exist
in space. The possibility that life may have started from such
compounds that arrived on Earth on a comet, meteor, or dust.
- Uprooting the Tree of Life
W. Ford Doolittle
Scientific American, February 2000, pp. 90-95
- Just 10 years ago biologists thought they had worked out
how the earliest cells evolved. Since then, studies of ribosomal
RNA have indicated a more complex theory may be needed.
It is possible that prokaryotes, archaea, and eukaryotes
arose somewhat independently from more primitive types
- Polarized Starlight and the Handedness of Life
American Scientist, July-August 1999, pp. 336-343
- Chiral molecules such as amino acids and sugars are generally
found in only one of their enantiomeric forms in terrestrial
life. The explanation for this may be traceable to circular
polarization of starlight in space.
Life's Far-Flung Raw Materials
Max P. Bernstein; Scott A. Standford; Louis J. Allamandola
Scientific American, July 1999, pp. 42-49
- Complex organic molecules are abundant in interstellar clouds.
Such molecules that survived the formation of the solar system
may have given rise to life on Earth.
The Beginnings of Life on Earth
Christian de Duve
American Scientist, September-October 1995, pp. 428-437
- Life began on Earth about 4 billion years ago through a long
succession of chemical steps. In spite of the complexity of the
process, the outcome in the form of life as we know it may have
been almost inevitable from the existing conditions.
- Synthetic Self-Replicating Molecules
Julius Rebek, Jr.
Scientific American, pp. 48-55
- One approach to research into the origins of life is to
try to recreate important biological molecules by simulated
natural processes. An alternative is to experiment with
self-replication in carefully designed but non-biological
- Handedness, Origin of Life and Evolution
Valdik A. Avetisov; Vitalii I. Goldanskii; Vladimir V. Zuz'min
Physics Today, July 1991, pp. 33-41
- The physics of symmetry breaking may shed some light on the
origins of life. Proteins are constructed only from left-handed
amino acids, while DNA contains only right-handed sugars. This
could be an important clue to how such biological molecules
- Christopher Wills; Jeffrey Bada -- The Spark of Life: Darwin and
the Primeval Soup
Perseus Publishing, 2000
- Wills and Bada present theories of the origins of life from a
historical perspective. Their own theory is that life originated
in a chemical process of natural selection on the Earth's
surface. They consider the implications for the existence of life
elsewhere in the universe.
- Iris Fry -- The Emergence of Life on Earth: A Historical and
Rutgers University Press, 2000
- As the subtitle suggests, a historically-oriented overview
is presented of a variety of theories about the origins of life.
The possibility of life on other planets is considered.
- Noam Lahav -- Biogenesis: Theories of Life's Origins
Oxford University Press, 1999
- The author presents a more detailed and technical account of
current theories of the origin of life than is attempted in most
books for a general audience. The book is in four parts: the
history of enquiries into the origins of life, the basic biological
facts that need to be accounted for, the "arena" in which life
emerged, and the varieties of theories which try to explain the
emergence of life.
- Freeman Dyson -- Origins of Life
Cambridge University Press, 1999
- In this short book Dyson focuses on two essential characteristics
of "life": replication and metabolism. He outlines the two types of
theories of life's origin: those which assume replication came first
(the majority) and those which assume metabolism was first.
- André Brack, ed. -- The Molecular Origins of Life:
Assembling Pieces of the Puzzle
Cambridge University Press, 1998
- This is a collection of papers by a number of experts in the
subject. Most papers present detailed accounts of the ancient
environments in which life could have arisen and of possible
chemical pathways leading to life.
Scientists Debate RNA's Role At Beginning Of Life On Earth
The Scientist, March 1997
- Before there was life, there were chemicals. The idea that
ribonucleic acid (RNA), because of its catalytic capability
and multiple roles in protein synthesis, was the chemical
that led directly to life is termed the RNA world hypothesis.
- Harold J. Morowitz – Beginnings of Cellular Life:
Metabolism Recapitulates Biogenesis
Yale University Press, 1992
- Morowitz offers a relatively brief monograph that sets out
his own views of how cellular life came about. In his model,
cells originate first, followed by proteins, with genes coming
last. Much attention is given to the biochemistry hypothesized
to be involved in the origins of life.
- Christian de Duve – Blueprint for a Cell: The Nature
and Origin of Life
Carolina Biological Supply Company, 1991
- de Duve, a Nobel laureate, lays out in technical but
comprehensible details the essentials of cell biology and how
it could have originated. The first half of the book covers the
elements of cell biology, while the second explores the physics
and chemistry that could have led to the origin of cells.
- A. G. Cairns-Smith -- Seven Clues to the Origin of Life
Cambridge University Press, 1985
- The question of how life may have arisen on Earth is addressed
in the spirit of a detective story. The author eventually develops
his theory that clay played an essential role in the chemical
reactions that led to life.
Copyright © 2002 by Charles Daney, All Rights Reserved