Cosmic ancestry

From Wikipedia, the free encyclopedia

 This article does not cite any references or sources. (January 2008)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

Cosmic ancestry is a hypothesis of the origin of life on Earth, based on the panspermia views of Fred Hoyle and Chandra Wickramasinghe and further developed by Brig Klyce. It incorporates strong panspermia, the Gaia hypothesis and the premise that life has no primary origin.

Contents

[edit] History

Hoyle was a long-standing advocate of strong panspermia. He claimed (with Wickramasinghe) that spectral analysis of interstellar dust indicated that large organic molecules and even bacterial spores occur in space[1]. He also viewed natural selection and mutation as too weak a mechanism to drive evolutionary progress.[2] Moreover, his belief in a quasi-steady-state universe allowed him to consider the possibility that life was much older than orthodox cosmology would allow. Whilst Wickramasinghe and Hoyle referred to their ideas as either panspermia or cosmic ancestry[1] , the latter term has come to be associated with an expanded hypothesis proposed by Klyce, which incorporates the Gaia hypothesis of James Lovelock.

[edit] Theory

Cosmic ancestry holds that life is neither the product of supernatural creation, nor is it spontaneously generated through abiogenesis, but that it has always existed in the universe. It claims that the evolutionary progression from simpler to more complex organisms utilises pre-existing genetic information and does not compose this information as it occurs.

According to the hypothesis, higher life forms, including intelligent life, descend ultimately from pre-existing life which was at least as advanced as the descendants. The genetic programs for the evolution of such higher forms may have been delivered to biospheres, such as the Earth's, within viruses or bacteria in the same manner as proposed by other versions of panspermia. The genetic programs may then be installed by known gene transfer mechanisms. Also, according to cosmic ancestry, life initiates Gaian processes that may environmentally alter biospheres.

Cosmic ancestry is opposed to both neo-Darwinism and Intelligent design theories. Its assertions require the universe to be ageless.

[edit] Evidence

Evidence for the possible astral origin of life is summarised in theoretical panspermia.

Recent evidence suggests that mechanisms other than random mutation and natural selection could play an important role in evolution - it is now apparent that horizontal gene transfer is much more widespread than previously thought. There are also many instances of genes detected in species that have no known use for them[3][4][5]. It is claimed that other aspects of evolution which present problems for neo-Darwinism are more easily explained by cosmic ancestry or panspermia, such as life's rapid start on Earth[2], punctuated equilibrium and convergent evolution.

The primary justification for the hypothesis is claimed to be the lack of direct evidence that any natural process can (1) cause life to originate from non-living matter, or (2) compose genetic programs for new evolutionary features. Evidence for speciation, adaptation, variation, and optimization within narrow ranges via natural selection is not disputed.

[edit] Criticisms

Postulating that life (and the universe) have always existed is contrary to nearly all contemporary scientific views. The cosmic ancestry hypothesis has been largely ignored by the scientific community. Most biologists regard natural selection as an adequate (although not fully understood) and more plausible explanation for the evolution of life on Earth. Some evidence, such as Hoyle's interpretation of his spectral analysis, is widely disputed.

[edit] Notes

  1. ^ F. Hoyle and C. Wickramasinghe. "On the Nature of Interstellar Grains" p 77-90 v 66 Astrophysics and Space Science. 1979
  2. ^ F. Hoyle, Mathematics of Evolution p 97-109 ISBN 0-9669934-0-3; Memphis: Acorn Enterprises LLC, 1999
  3. ^ Ulrich Technau et al., "Maintenance of ancestral complexity and non-metazoan genes in two basal cnidarians" [abstract], doi:10.1016/j.tig.2005.09.007, p 633-639 v 21, Trend in Genetics, December 2005
  4. ^ Florian Raible et al., "Vertebrate-Type Intron-Rich Genes in the Marine Annelid Platynereis dumerilii", 10.1126/science.1119089, p 1325-1326 v 310, Science, 25 Nov 2005
  5. ^ Arne Kusserow et al., "Unexpected complexity of the Wnt gene family in a sea anemone", doi:10.1038/nature03158, p 156-160 v 433, Nature, 13 Jan 2005

[edit] See also