Chemical evolution has two meanings and uses. The first refers to the theories of evolution of the chemical elements in the universe following the Big Bang and through nucleosynthesis in stars and supernovas. A chemical element, often called simply element, is a chemical substance that cannot be decomposed or transformed into other chemical substances by ordinary chemical methods. ... According to the Big Bang theory, the universe emerged from an extremely dense and hot state (bottom). ... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ... The Pleiades star cluster A star is a massive body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. ... Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ...

The second use of chemical evolution or chemosynthesis is as a hypothesis to explain how life might possibly have developed or evolved from non-life (see abiogenesis). Various experiments have been made to show certain aspects of this process, the first ones were done by Stanley L. Miller in the 1950s. For that they are now called Miller experiments. However only very basic organic building blocks were obtained. The challenge is getting complex molecules organized consistently. Look up life, living in Wiktionary, the free dictionary. ... Abiogenesis (Greek a-bio-genesis, non biological origins) is, in its most general sense, the generation of life from non-living matter. ... Stanley L. Miller (born 1930) is an American chemist famous for his role in the Miller-Urey experiment he performed in 1953, while a graduate student. ... The 1950s were a decade that spanned the years 1950 through 1959, although some sources say from 1951 through 1960. ... The Miller-Urey experiment attempts to recreate the chemical conditions of the primitive Earth in the laboratory, and synthesized some of the building blocks of life. ...

The hypothesis is that simple chemical compounds could catalyze the creation of copies of themselves (somewhat similar to the formation of a crystal or polymer) in an environment rich with the necessary building block compounds or elements. As these chemical replicators "reproduce", they can be created with slightly different structures randomly, similar to biological mutations. Eventually these replicators would produce protocells. It has been suggested that crystallization processes be merged into this article or section. ... Polymer is a term used to describe a very long molecule consisting of structural units and repeating units connected by covalent chemical bonds. ... In biology, mutations are changes to the genetic material (usually DNA or RNA). ... This article focuses on modern scientific research on the origin of life. ...

See also

• Primordial nucleosynthesis
• Stellar nucleosynthesis
• Supernova nucleosynthesis
• Cosmic ray spallation
• Origin of life
• RNA world hypothesis
• Self-replication
• Hypercycle
• Self-assembly
• Autopoiesis

In cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. ... Cross section of a red giant showing nucleosynthesis and elements formed Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the heavier elements. ... Composite image of Keplers supernova from pictures by the Spitzer Space Telescope, Hubble Space Telescope, and Chandra X-ray Observatory. ... Cosmic ray spallation is a form of naturally occuring nuclear fission and nucleosynthesis. ... Pre-Cambrian stromatolites in the Siyeh Formation, Glacier National Park. ... The RNA world hypothesis proposes that RNA was actually the first life-form on earth, later developing a cell membrane around it and becoming the first prokaryotic cell. ... Self-replication is the process by which some things make copies of themselves. ... The quasispecies [kwaa-zei-spee-seez] model is a description of the process of the Darwinian evolution of self-replicating entities within the framework of physical chemistry. ... Self-assembly is the fundamental principle which generates structural organization on all scales from molecules to galaxies. ... Autopoiesis literally means auto (self)-creation (from the Greek: auto - αυτό for self- and poiesis - ποίησις for creation or production) and expresses a fundamental complementarity between structure and function. ...

External links

• Chemosynthesis: A Theory for the Chemical Development of Life Accessed Jan. 3, 2006

Creationist/Intelligent design criticism

• Problems with the Natural Chemical "Origin of Life"