The Definition of Life; and, Taxonomy as We Know It
April 15, 2008
In order to make sense of our surroundings, we, as humans, constantly group things into discrete catagories--states of matter, times of day, types of clothes, etc.
Since Linnaeus, we have consistantly grouped life in boxes-within-boxes, based on physical characteristics. The advent of nucleic acid sequencing changed some of these early notions of taxonomy. But now, as we discover more about life, specifically of our microbial counterparts and their viruses, we are coming to the realization that Linnaein taxonomy is not sufficient. Especially if our motivation for using taxonomy is to deduce evolutionary relationships.
Viral taxonomy has some very specific shortfalls. Researchers in this 2002 Journal of Bacteriology article, lay out these shortcomings. One striking point is that with viruses, structure alone is not sufficient to characterize a phage into species. The figure here shows two similar looking phages with very different DNA sequence. This concept could easily be applied to a variety of other viruses.
Another problem, is that species is defined as organisms that share a common gene pool. Viruses are constantly moving genetic information into and out of hosts. Many viruses have the ability to cross-infect more than one host as well. This means that the gene pool available to an organism crosses most borders of what we traditionally define as species.
Continue reading about viral taxonomy at Blogging for Bacteriophages.
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Comments
Tomorrow's comprehension of life
June 5, 2008 by Anonymous, 1 year 22 weeks ago
Comment id: 30540
Proposed Definitions Of Earth Life, Organism And Gene.
http://www.physforum.com/index.php?showtopic=14988&st=225&#entry346136
Earth Life: 1. a format of temporarily constrained energy, retained in temporary constrained genetic energy packages in forms of genes, genomes and organisms 2. a real virtual affair that pops in and out of existence in its matrix, which is the energy constrained in Earth's biosphere.
Earth organism: a temporary self-replicable constrained-energy genetic system that supports and maintains Earth's biosphere by maintenance of genes.
Gene: a primal Earth's organism.
Suggesting,
Dov Henis
http://blog.360.yahoo.com/blog-P81pQcU1dLBbHgtjQjxG_Q--?cq=1
What is life?
August 12, 2008 by Anonymous, 1 year 12 weeks ago
Comment id: 31486
Hi,
I got my own definition of life, what do you think of it:
Life is the state of matter in which organised matter is able to convert matter into energy (or extract energy from matter) by its own means and for its own purpose.
Vlad Voicu
Romania
SCIENTISTS IGNORING EVIDENCE OF HUMAN OVERPOPULATION OF EARTH
April 20, 2008 by Anonymous, 1 year 28 weeks ago
Comment id: 29155
A CLARION CALL FOR CLIMATE ACTION
A particularly pernicious disturbance exists in the human community. ELECTIVE MUTISM is one of the great, clear and present dangers to human and environmental health. It is a worldwide “plague†in our time from which many too many in the vast community of science suffer egregiously. That elective mutism has afflicted so many in the social sciences is one thing. The family of humanity can understand, I suppose, how social scientists do not possess the most adequate expertise to speak out loudly and clearly regarding the emerging and converging global challenges derived from the human overpopulation of Earth.
On the other hand, what I find reprehensible and unbelievable is the way scientists with appropriate expertise in the physical and biological sciences, whatever their excuses, are choosing not to fullfil their professional responsibilities and not to discharge duties only they can perform. Their willful refusal to comment on good scientific evidence of the human species’ overpopulation of the planetary home God blesses us to inhabit is as unacceptable as it is perverse.
Sincerely,
Steve
Steven Earl Salmony
AWAREness Campaign on The Human Population,
established 2001
http://sustainabilitysoutheast.org/