Re: Speciation and biodiversity, a neutral theory

On Thu, 16 Jul 2009 12:29:33 -0700 (PDT), Dov Henis
<henisdov@xxxxxxxxxxxxxxxx> wrote:

On 16 ????, 20:10, r norman <r_s_nor...@xxxxxxxxxxx> wrote:
A paper in the current issue of Nature

  Global patterns of speciation and diversity
  M. A. M. de Aguiar, M. Baranger,
    E. M. Baptestini, L. Kaufman & Y. Bar-Yam
  Nature 460(No. 7253):384-387(16 July 2009)

expands on Hubbell's neutral theory of biodiversity with a model
simulation that produces speciation in the absence of selection or
geographical isolation.  "We used agent-based simulations in which
agents identified by geographical location and genotype undergo sexual
reproduction in pairs limited by geographical and genetic proximity.
Each offspring replaces a parent and differs in genotype according to
genetic inheritance from both parents, with crossover and mutation,
and in geographical location by dispersal."

They conclude: "Our biodiversity results provide additional evidence
that species diversity arises without specific physical barriers. This
is similar to heavy traffic flows, where traffic jams can form even
without accidents or barriers."

In other words, hurray for complexity theory and emergent
properties!!!

An accompanying review explains it well:

  Ecology: Towards a theory of biodiversity
  Jayanth R. Banavar and Amos Maritan
  Nature 460(No. 7253):334-335(16 July 2009)

this describes the work in physical terms (since the two reviewers are
physicists):

  "Life is a non-equilibrium phenomenon involving a ?dual-diffusion?
process. Organisms diffuse and distribute themselves in space, and
compete for resources, such as light, water and nutrients. At the same
time, on different timescales, there is diffusion in ?genome space?
that leads to new species and serves to maintain diversity. The
evolution of an ecological community corresponds to the dynamics of
the distribution of occupied regions in real space and genome space,
and the development of interactions between the two...."

"Hubbell?s <the 2001 earlier theory> simplifying idea was to treat all
species at the same trophic level (position in a food chain) as
equivalent to each other. The rarity of one species and the high
abundance of another do not result from their distinctive traits, but
rather from stochastic drift in populations of essentially identical
species. Species diversity comes about not from differences among
species, as highlighted in niche theory, but rather from the interplay
between extinction caused by random drift in species populations and
the introduction of new species by either immigration from a
surrounding region or speciation."

"In the new paper, de Aguiar et al. present computer simulations of a
specific neutral model of dual diffusion along with the process of
sexual reproduction. Previous approaches took into account diffusion
in real space and postulated the appearance of new species through
mutation without explicit consideration of the evolution of the
genetic codes of the breeding organisms. In the simulations, de Aguiar
et al. observe the spontaneous emergence of species, a group of
individuals with genetic codes occupying a sub-region of the whole
genome space, living in a sub-region of the space available to the
community."

"Remarkably, the results of the simulations, with many adjustable
parameters, are in good accord with a variety of observed patterns.
Examples of such patterns are the constant rate of speciation observed
in the fossil record; the higher diversity of freshwater ray-finned
fishes than of their marine counterparts; the species?area
relationships of birds, flowering plants and tropical-forest trees;
and the relative species abundance of birds and forest trees."

The editor's summary and links to the two papers are free at

http://www.nature.com/nature/journal/v460/n7253/edsumm/e090716-09.html
but the full text requires paid access.

There is also a blurb about it by Jef Aks called "Spontaneous
Speciation" in The Scientist at
 http://www.the-scientist.com/blog/display/55825/
which I think may be available free.

=======================
Spontaneous Speciation?
Again And Again: It's Culture That Drives Evolution
Not Occasional Genetic Accidents


Re "Spontaneous speciation?"
http://www.the-scientist.com/blog/display/55825/

Again and again:

A. Earth's primal organisms, Genes, and their take-offs, all Earth
organisms, are temporary energy packages. The more of them there are
the more enhanced is the biosphere, Earth's life, Earth's storage of
temporarily constrained energy. This Is Nature's Drive And Purpose Of
Life. This Is The Origin, The Drive, The Archetype, Of Selected Modes
Of Survival.

B. From http://www.physorg.com/news151319378.html
I have been presenting evidence for years that adaptation, i.e.
culture, is the driver of evolution of all life including human and,
yes, of all other, inanimate materials, and that genetic evolution is
generally biased, not random.

NO NO NO. The drive of evolution is NOT RANDOM change followed by
survival selection. It is biased, as explained in my "Updated Life's
Manifest" and elaborated in my posts about the nature and role of
culture in evolution. In evolution of ALL materials, including life.

C. From http://www.the-scientist.com/community/posts/list/160/122.page#2753
"Origin Of Origins"
Earth Life is but one specimen of myriad of materials being formed and
attempting to survive for temporarily constraining energy. This is the
essence of the ongoing Big Bang.


Dov Henis
(Comments From The 22nd Century)
Updated Life's Manifest May 2009
http://www.physforum.com/index.php?showtopic=14988&st=480&#entry412704
http://www.the-scientist.com/community/posts/list/140/122.page#2321

Somehow I feel reassured that the big bang lives on in you and me.

And now I see that culture is not really just a human phenomenon. That
is why we do have tissue culture and bacterial cultures -- culture
goes all the way back to the origin of life.

.

Relevant Pages

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