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| An entity with the above properties is considered to be a ''living'' organism, that is an organism that is alive hence can be called a life form. However, not every definition of life considers all of these properties to be essential. For example, the capacity for descent with modification is often taken as the only essential property of life. This definition notably includes ]es, which do not qualify under narrower definitions as they are ] and do not metabolise. Broader definitions of life may also include theoretical ] and other ]. | An entity with the above properties is considered to be a ''living'' organism, that is an organism that is alive hence can be called a life form. However, not every definition of life considers all of these properties to be essential. For example, the capacity for descent with modification is often taken as the only essential property of life. This definition notably includes ]es, which do not qualify under narrower definitions as they are ] and do not metabolise. Broader definitions of life may also include theoretical ] and other ]. | ||
| LIFE IS BULLSHIT.......... | |||
| LIFE IS BULLSHIT.......... | |||
| ==Extraterrestrial life== | ==Extraterrestrial life== | ||
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Life is a condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally. A diverse array of living organisms can be found in the biosphere on Earth. Properties common to these organisms – plants, animals, fungi, protists, archaea and bacteria – are a carbon and water-based cellular form with complex organization and genetic information. They undergo metabolism, possess a capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt to their environment in successive generations.
An entity with the above properties is considered to be a living organism, that is an organism that is alive hence can be called a life form. However, not every definition of life considers all of these properties to be essential. For example, the capacity for descent with modification is often taken as the only essential property of life. This definition notably includes viruses, which do not qualify under narrower definitions as they are acellular and do not metabolise. Broader definitions of life may also include theoretical non-carbon-based life and other alternative biology.
Extraterrestrial life
- Main articles: Extraterrestrial life, Astrobiology
Earth is the only planet in the universe known to harbour life. The Drake equation has been used to estimate the probability of life elsewhere, but scientists disagree on many of the values of variables in this equation (although strictly speaking Drake equation estimates the number of extraterrestrial civilizations in our galaxy with which we might come in contact - not probability of life elsewhere). Depending on those values, the equation may either suggest that life arises frequently or infrequently. Drake himself estimated the number of civilizations in our galaxy with which we might expect to be able to communicate at any given time as equal to one.
Relating to the origin of life on Earth, panspermia and exogenesis are theories proposing that life originated elsewhere in the universe and was subsequently transferred to Earth perhaps via meteorites, comets or cosmic dust. However those theories do not help explain the origin of this extraterrestrial life.
See also
- Biology - the scientific study of life
- Artificial life
- Extraterrestrial life
- Cellular life
- Non-cellular life
- Cellular automata
- Extremophile - Organisms that live in so called 'extreme' conditions e.g. hydrothermal vents
- Biological kingdom
- Origin of life
- Death
- Gaia hypothesis
- Taxonomy - the science of describing, categorising and naming organisms
- Phylogenetics - is the study of evolutionary relatedness among species
- Conway's Game of Life - simple mathematical 'cellular automaton' that mimicks the dynamics of an ecosystem.
References
Bibliography
- Kauffman, Stuart. The Adjacent Possible: A Talk with Stuart Kauffman. Retrieved Nov. 30, 2003 from
- Lynn Margulis and Dorion Sagan - What Is Life? (1995). Simon & Schuster. ISBN 0-684-81087-5
- Erwin Schrödinger - What is Life? (1944 to 2000). Cambridge University Press (Canto). ISBN 0-521-42708-8
- Walker, Martin G. LIFE! Why We Exist...And What We Must Do to Survive ( Wiki Book Page) ( Web Site), Dog Ear Publishing, 2006, ISBN 1-59858-243-7
Notes
External links
- What is Life and Aging? A Basic Introduction to Biology
- Wikispecies - a free directory of life
- "The Adjacent Possible: A Talk with Stuart Kauffman"
- Life; birth to death, answers to some common questions
- Life's Rational Meaning - life's origin and trajectory through the fundamental philosophy of existence
- Stanford Encyclopedia of Philosophy entry
- The Biologist: Biology
- Magazin Haberleri Güncel Magazin Hayatın En Güzel Anı Life Magazin
- Life under extreme conditions An in depth look at how life can form under the most extreme conditions.