Megatrajectory
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Megatrajectory is a theoretical concept in evolutionary biology that describes paradigmatic developmental stages and potential directionality in the evolution of life.
Posited by A. H. Knoll and R. K. Bambach in their 2000 collaboration, "Directionality in the History of Life," Knoll and Bamback argue that, in consideration of the problem of progress in evolutionary history, a middle road that encompasses both contingent and convergent features of biological evolution may be attainable through the idea of the megatrajectory:
We believe that six broad megatrajectories capture the essence of vectoral change in the history of life. The megatrajectories for a logical sequence dictated by the necessity for complexity level N to exist before N+1 can evolve...In the view offered here, each megatrajectory adds new and qualitatively distinct dimensions to the way life utilizes ecospace.
– [1]
According to Knoll and Bambach, the six megatrajectories outlined by biological evolution thus far are:
- the origin of life to the "Last Common Ancestor"
- prokaryote diversification
- unicellular eukaryote diversification
- multicellular organisms
- land organisms
- appearance of intelligence and technology
Milan Ćirković and Robert Bradbury[2][3], have taken the megatrajectory concept one step further by theorizing that a seventh megatrajectory exists: postbiological evolution triggered by the emergence of artificial intelligence at least equivalent to the biologically-evolved one, as well as the invention of several key technologies of the similar level of complexity and environmental impact, such as molecular nanoassembling or stellar uplifting.
[edit] References
- ^ Knoll, A. H.; R. K. Bambach (2000). "Directionality in the history of life: diffusion from the left wall or repeated scaling of the right". Paleobiology 26 (4): 1-14. doi:.
- ^ Milan M. Cirkovic and Robert J. Bradbury (2006-06-21). "Galactic Gradients, Postbiological Evolution and the Apparent failure of SETI" arxiv:astro-ph/0506110.
- ^ M. M.Cirkovic, I. Dragicevic, and T. Beric-Bjedov (2005). "ADAPTATIONISM FAILS TO RESOLVE FERMI’S PARADOX" (PDF). Serb. Astron. J. 170: 89–100.
[edit] Further reading
- F Westall (October 2003). "Stephen Jay Gould, les procaryotes et leur evolution dans le contexte geologique". Comptes Rendus Palevol 2 (6): 485–501. doi:.
- Kenneth J. McNamara (November 2002). "Paleobiology — Bridging the Gap". Biology and Philosophy 17 (5): 729–738. Springer Netherlands. doi:.
- Walter Etter. "16: Patterns of Diversification and Extinction", Handbook of Paleoanthropology (PDF), Springer Berlin Heidelberg, 441–501. DOI:10.1007/978-3-540-33761-4_16. ISBN 978-3-540-32474-4.
