Over the past two decades, scientific advances in several disciplines have changed our view of the origin and evolution of life on Earth. In written testimony to the "Life in the Universe" hearings held by the House Subcommiteee on Space and Aeronautics astrobiologist Jack Farmer of the NASA Astrobiology Institute describes how these scientific developments have expanded the possibilities for the existence of life within our the Solar System and outside it. Biologists formerly described life in terms of five kingdoms of life Animals, Plants, Fungi, Protists and Monera (Bacteria). Now they think in terms of three major domainsÂArchaea, Bacteria, and EukaryaÂof which the traditional kingdoms are merely an offshoot, small branches on the tree of life. Most life forms in these three domains are single-celled organisms, which dominated the first 85% of life's history. Life arose relatively quickly after the early bombardment of the Earth by comets tapered off. The earliest known life forms all thrive at very high temperatures, leading many scientists to conclude that life originated at high temperatures. Farmer, however, believes that heat-loving organisms were simply the only forms of life to survive the last giant comet or asteroid impact. Microbes have been found to survive a wide range of extreme conditions besides high temperatures. The limits that life can endure are much broader than once thought. on Earth, wherever there is liquid water, an energy source, and basic nutrients, there is life. Organisms have been found under the ocean floor, suggesting that underground water on Mars might provide a habitat for life. Cold temperatures can preserve microbes, meaning that past or present life forms might be found in the polar ice caps of Mars or the icy crust of Europa.
May 25, 2007 | SCIENCE
Legendary origins of life researcher Stanley Miller
(University of California, San Diego) - Miller was a member of the first generation of researchers funded by NASAs exobiology research program, now a part of the Astrobiology Program, and remained active in exobiology/astrobiology research for decades. In recent years, Miller served as a member of the NASA Astrobiology Institutes Europa Focus Group.
Apr 05, 2007 | SCIENCE
Rethinking Species
(American Society for Microbiology) - Microbiologists are rethinking the ways in which they define and classify microbial species. Studying microbes and understanding how they are related to one another throughout evolutionary time is important in determining how life originated on our planet.
Mar 21, 2007 | SCIENCE
Norman Pace is receiving Microbiologys 2007 Abbott-ASM Lifetime Achievement Award
(NASA, ASM) - Norman Pace, professor of molecular, cellular, and developmental biology at the University of Colorado in Boulder, is receiving the American Society for Microbiology's 2007 Abbott-ASM Lifetime Achievement Award for outstanding contributions to the field of microbial ecology. Dr. Pace is a member of the NASA Astrobiology Institute research team headed by the University of Colorado Center for Astrobiology. This team is studying the origin of stars and planets, development of habitable planets, "RNA World" and the origins of life, biological evolution on Earth, energetics of life on other planets, and philosophical aspects of astrobiology and the search for life elsewhere.
Feb 25, 2007 | SCIENCE
The Birth of the Sun
(University of Colorado) - Astronomers have gazed at the embryo of an infant star that may one day develop into a virtual twin of our own Sun. The finding may be a rare opportunity to understand how the early Sun developed and shaped the environment of our solar system.
Sep 23, 2005 | SCIENCE
Marine Microorganism Suspected to Play Role in Global Carbon and Nitrogen Cycles
(NSF) - Scientists successfully culture the first Archaea known to oxidize ammonia for energy and metabolize carbon dioxide.
Dec 27, 2002 | SCIENCE
Evolution's Sweet Tooth
(Astrobiology Magazine) - How did intelligence evolve? A scientist studying differences between humans and great apes may have found a biochemical step in that direction.
Dec 04, 2002 | SCIENCE
Are Aliens a Bunch of Smarty-Pants?
(Astrobiology Magazine) - Scientists debate how long it takes to grow a brain.
Oct 28, 2002 | SCIENCE
Concerted Evolution
(Astrobiology Magazine) - Statistical analysis reveals that patterns in genes resemble good musical
structure. The patterns may reveal how genes evolved.
Oct 15, 2002 | SCIENCE
Studying Evolution with Digital Organisms
(Astrobiology Magazine) - Digital organisms that exist only as computer code may lead to a new understanding of evolution.
Oct 01, 2002 | SCIENCE
Video: an Interview with Andrew Knoll
(NASA Astrobiology Institute) - A world without elephants? Paleontologist Andrew Knoll discusses what he calls "the biotic crisis."
Sep 12, 2002 | SCIENCE
Life Reached Land a Billion Years Ago
(Life Reached Land a Billion Years Ago) - Possible traces of the first organisms ever to inhabit the land have been identified in northwestern Scotland.
Aug 01, 2002 | SCIENCE
Eukaryotic Origins: Revolution in the Classification of Life
(Astrobiology Magazine) - Was the nucleus of a cell once a separate bacterium that was engulfed by another microbe?
Jul 08, 2002 | SCIENCE
Protecting the Planet: Q&A with Asteroid Hunter David Morrison
(Space.com) - Morrison describes the hunt for objects that could pose a potential threat to Earth.
Jun 04, 2002 | SCIENCE
Stephen Jay Gould Remembered
(SF Chronicle) - Gould argued that evolution proceeds not smoothly, but in fits and starts.
May 17, 2002 | SCIENCE
Age of Dinosaurs Bracketed by Asteroid or Comet Impacts
(Columbia Univ.) - New research bolsters the theory that the age of dinosaurs not only ended with an asteroid or comet impact, but began with one as well.
Mar 14, 2002 | SCIENCE
Exploding Star May Have Sparked Earth Disaster
(CNN) - Scientists argue that a nearby supernova caused a mini-extinction of marine life 2 million years ago.
Feb 14, 2002 | SCIENCE
Wrenching Tides on Europa Could Force Life to Evolve
(Space.com) - Ruptures in Europa's icy crust might permit photosynthesis and compel life to adapt rapidly.
Dec 18, 2001 | SCIENCE
Test-tube RNA
(NASA Astrobiology Institute) - Scientists have produced evidence that life may have evolved from RNA.
Nov 08, 2001 | SCIENCE
Astrobiologists to Launch Mission to Early Earth
(Univ. of Rochester) - Researchers from the University of Rochester are burrowing deep underground to determine the signature of early life.
Nov 06, 2001 | SCIENCE
Hydrothermal Vents: Life's First Home?
(NASA Astrobiology Institute) - The discovery of vent life in early 1977 began a dramatic shift in the study of the origin of life
Oct 05, 2001 | SCIENCE
Genomics Meets Geology
(NASA Astrobiology Institute) - Researchers at the NASA Astrobiology Institute are combining chemistry, geological history and paleontology in an effort to better understand the origin and evolution of life on Earth.
Oct 02, 2001 | SCIENCE
Evolution's Double Take
(NASA Astrobiology Institute) - Researchers claim that hydrogenosomesÂcell components that allow some organisms to survive in oxygen-free environmentsÂhave repeatedly evolved from mitochondria in the course of evolution.
Sep 06, 2001 | SCIENCE
Asteroid or Comet Caused Earth's Largest Mass Extinction
(Space.com) - Scientists working in China have have unearthed additional evidence that the Permian-Triassic extinction was triggered by an asteroid or comet impact.
Aug 09, 2001 | SCIENCE
NASA Scientists Propose New Theory of Earth's Early Evolution
(NASA) - NASA scientists recently proposed a new explanation for the rise of oxygen in Earth's early atmosphereÂan event that may have jumpstarted the evolution of complex life.
Aug 08, 2001 | SCIENCE
Lightning Jumpstarts Evolution
(Nature) - Using laboratory-generated lighting, researchers have caused bacteria in soil to trade DNA with each other.
Aug 02, 2001 | SCIENCE
Did Tectonics Get an Early Start?
(NASA Astrobiology Institute) - The conditions necessary for complex life may have arisen earlier than previously thought.
Jul 19, 2001 | SCIENCE
Nitrates, Lightning Key to Life at Early Earth
(Space.com) - Researchers have helped to explain how proto-plants paved the way for life as we know it.
Jun 08, 2001 | SCIENCE
Jurassic Spark: Early Ancestor of Mammals Found
(NASA Astrobiology Institute) - The tiny mammal is 40 million years older than any mammalian fossil previously found.
Apr 27, 2001 | SCIENCE
Asteroid/Comet Impacts and Human Evolution
(Space.com) - A pair of British scientists argue that asteroid or comet impacts may have influenced human evolution.
Apr 11, 2001 | SCIENCE
Twenty Thousand Leagues under the Sea
(NASA Astrobiology Institute) - An expedition to geysers on the floor of the Indian Ocean is studying how animals there evolve and disperse geographically.
Mar 21, 2001 | SCIENCE
Evo devo learns a larval lesson
(NASA Astrobiology Institute) - Scientists have studied the life history of animals, part of a field called development, for many decades. Other scientists have studied how life arose and evolved on Earth. For the first time since the early part of this century, the two fields are coming together, in a new discipline called "Evo Devo."
Mar 08, 2001 | SCIENCE
Dinosaurs may have died off quickly
(BBC) - New research supports the idea that an asteroid or comet impact wiped out the dinosaurs.
Feb 19, 2001 | SCIENCE
Evolution: land plants divided and ruled
(Nature) - Two very different groups of plants used the same trick to get a foothold on land.
Feb 05, 2001 | SCIENCE
The oldest life on land
(NASA Astrobiology Institute) - Fossilized remnants of a microbial mat provide evidence that life existed on land as early as 2.6 to 2.7 billion years ago. The findings suggest that an oxygen atmosphere and a protective ozone layer were in place around Earth by that time.
Jan 18, 2001 | SCIENCE
Astrobiologists find evidence of early life on land
(NASA Astrobiology Institute) - Scientists with NASA's Astrobiology Institute have discovered evidence that microbial life emerged on land between 2.6 billion and 2.7 billion years ago, much earlier than previously thought.
Oct 19, 2000 | SCIENCE
New species emerge faster than previously thought
(BBC) - Salmon in a lake have split into separate species in just 60-70 years.
Oct 12, 2000 | SCIENCE
Origin of sexual reproduction remains a mystery
(BBC) - A study casts doubt on the accepted theory of why sexual reproduction evolved.
Oct 09, 2000 | SCIENCE
Do mammoth bones hold clues to mass die-off?
(MSNBC/AP) - A researcher argues that a virus wiped out most species of large mammals 13,000 years ago.
Oct 02, 2000 | SCIENCE
First salt-loving bug sequenced
(BBC) - Scientists have cracked the genetic code of a microbe that thrives in extremely salty water. The findings could help astrobiologists determine the limits that life can endure.
May 31, 2000 | SCIENCE
Evidence that dinosaurs died quickly from asteroid impact
(CBC) - A new study of the fossil record suggests that dinosaurs became extinct abruptly. The finding supports the theory that they were wiped out by an asteroid.
Jan 01, 2000 | SCIENCE
Snowball Earth
(Scientific American) - The climate of ancient Earth may have seesawed between kilometer-thick ice covering the planet and sweltering heat. The drastic swings may have given rise to multicellular life forms.
Oct 11, 1999 | SCIENCE
How an asteroid impact causes extinction
(explorezone.com) - Objects from space may have played a crucial role in the evolution of life on Earth.
Aug 28, 1999 | SCIENCE
Debate: were mass extinctions caused by impacts or volcanoes?
(New Scientist) - In this book review, a scientist discusses possible causes of mass extinctions 65 million years ago, including a comet or asteroid impact, and an increase in volcanic activity.
Aug 06, 1999 | SCIENCE
All green land plants may share common ancestor
(Science Daily) - Genetic research suggests that all green land plants may have descended from a single freshwater algae.
Aug 03, 1999 | SCIENCE
"Sloppy copy" discovery sheds light on evolution
(UniSci) - Researchers have established how ultraviolet radiation leads to genetic mutation in a type of bacteria.
Aug 03, 1999 | SCIENCE
Nearby Supernova May Have Caused Mini-Extinction
(Science Daily) - Radioactive material beneath the ocean floor could have been left by a supernova 5 million years ago.
Jan 13, 1995 | SCIENCE
Exploding Star May Have Caused Earthly Extinctions
(AP) - Radiation from a nearby supernova may have devasted life on Earth 225 million years ago.
