Start Encyclopedia69 Dictionary | Overview | Topics | Groups | Categories | Bookmark this page.
dictionary -  encyclopedia  
Full text search :        
   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z   #   




  Biopoiesis (Greek, ‘making life’), in the life sciences, is an explanation of how life on Earth originated from non-living matter. The age of the Earth is estimated at around 4.5 billion years while the Transvaal Fig Tree Chert fossils, estimated to be around 3.1 billion years old, contain bacteria and blue-green algae. Thus it seems likely that the first living organisms appeared within a few hundred million years of the Earth\'s formation.

Some scientists have proposed that life arrived on Earth from space (panspermia), but proponents of biopoiesis argue that this possibility does not invalidate their ideas since life, as it exists on Earth, must have arisen somewhere at some time. The theory has its roots in the 1920s, with J.B.S. Haldane in the UK and A.I. Oparin in the USSR who proposed that conditions on Earth at the time when life arose were very different from the modern environment. Oparin suggested that simple molecules in solution were able to interact under these conditions to form, at random, complex organic (carbon-containing) molecules, some of which were able to replicate themselves by acting as templates. Given sufficient time it was suggested that the components of this ‘soup’ would interact, again at random, giving rise occasionally to particular combinations which had special characteristics such as a membrane surrounding them and separating them from the environment. A living organism may be defined as a unit which is capable of reproducing itself and of interacting with its environment. Biopoiesis thus suggests how such a simple organism, called a eobiont (Greek, ‘Dawn Life’) might have originated and given rise to life on Earth today through the processes of biogenesis and evolution.

These ideas were largely hypothetical and as such were the target of criticism from many on the grounds that they were too far-fetched, and from creationists who claimed that they were blasphemous. However, starting in the 1950s a number of experiments were carried out which vindicated Haldane and Oparin. Reaction vessels containing solutions of chemicals thought likely to have be present on the primordial Earth were subjected to ultraviolet radiation or to electrical discharge and a wide variety of organic compounds was rapidly formed. Subsequently it has been demonstrated that many of the molecular pre-requisites for life can be formed under similar conditions. RB

See also abiogenesis; biochemistry; natural selection.Further reading Freeman Dyson, Origins of Life; , Salvador Luri, The Unfinished Experiment.



Bookmark this page:



<< former term
next term >>


Other Terms : Platonism | Law Of Nature | Liturgy
Home |  Add new article  |  Your List |  Tools |  Become an Editor |  Tell a Friend |  Links |  Awards |  Testimonials |  Press |  News |  About |
Copyright ©2009 GeoDZ. All rights reserved.  Terms of Use  |  Privacy Policy  |  Contact Us