| Topic: |
Religions > Atheism |
| User: |
"johac" |
| Date: |
20 Mar 2007 12:53:44 AM |
| Object: |
Bird speciation in Idaho? |
Interesting exmple of coevolution.
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New bird species found in Idaho
New finch species demonstrates the co-evolutionary arms race
One does not expect to discover a bird species new to science while
wandering around the continental United States. Nor does one expect that
such a species would provide much insight into how coevolutionary arms
races promote speciation. On both fronts a paper to appear in The
American Naturalist proves otherwise. Julie Smith, now at Pacific
Lutheran University, and her former graduate advisor, Craig Benkman at
the University of Wyoming, have uncovered strong evidence that
coevolution has led to the formation of a species of bird new to science
in the continental United States. Benkman discovered in 1996 what
appears to be a new species restricted to two small mountain ranges in
southern Idaho (the South Hills and Albion Mountains). This species is a
morphologically and vocally distinct "call type" of red crossbill (Loxia
curvirostra complex), which is a group of seed-eating finches
specialized for extracting seeds from conifer cones. Fieldwork by Smith
has revealed some of the mechanisms that have contributed to the nearly
complete cessation of interbreeding between this crossbill and other
call types that move into the South Hills every year. Perhaps most
remarkable is that this new crossbill evolved because of a
coevolutionary arms race between crossbills and lodgepole pine (Pinus
contorta) in the last five to seven thousands years.
As South Hills crossbills exerted selection on lodgepole pine for
increased seed defenses, lodgepole pine in turn exerted selection on
crossbills for larger bills to deal with these increased seed defenses.
This coevolution has caused these crossbills to diverge substantially in
bill morphology from other crossbills. Because the South Hills crossbill
is adapted to remove seeds from the well-defended cones there, it is a
superior competitor and thereby limits the less well adapted and nomadic
call types to breeding at very low frequencies in the South Hills. Such
ecological differences lead to premating (i.e., before mating)
reproductive isolation, which is nearly completed by strong assortative
pairing among the different call types (>99% of South Hills crossbills
pair with another South Hills crossbill). "This indicates that levels of
reproductive isolation characteristic of recognized species can evolve
rapidly even in the continued face of potential gene flow" says Benkman.
It also shows that coevolution can be a potent force for rapidly
generating biodiversity.
###
Julie W. Smith and Craig W. Benkman, "A coevolutionary arms race causes
ecological speciation in crossbills" American Naturalist. 2007.
169:455-465.
Founded in 1867, The American Naturalist is one of the world's most
renowned, peer-reviewed publications in ecology, evolution, and
population and integrative biology research. AN emphasizes sophisticated
methodologies and innovative theoretical syntheses‹all in an effort to
advance the knowledge of organic evolution and other broad biological
principles.
---
http://www.eurekalert.org/pub_releases/2007-03/uocp-nbs031607.php
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
.
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| User: "Al Klein" |
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| Title: Re: Bird speciation in Idaho? |
20 Mar 2007 10:21:23 PM |
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On Mon, 19 Mar 2007 22:53:44 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
New bird species found in Idaho
New finch species demonstrates the co-evolutionary arms race
Luddites will say "they're still birds" or "they're still finches".
.
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| User: "johac" |
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| Title: Re: Bird speciation in Idaho? |
20 Mar 2007 11:31:42 PM |
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In article <g491035gm6i243r6ru76tinu1ira6enm9p@4ax.com>,
Al Klein <rukbat@pern.invalid> wrote:
On Mon, 19 Mar 2007 22:53:44 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
New bird species found in Idaho
New finch species demonstrates the co-evolutionary arms race
Luddites will say "they're still birds" or "they're still finches".
I know. It's just "microevolution" to the ignoramuses.
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
.
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| User: "Al Klein" |
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| Title: Re: Bird speciation in Idaho? |
21 Mar 2007 07:50:28 AM |
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On Tue, 20 Mar 2007 21:31:42 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
In article <g491035gm6i243r6ru76tinu1ira6enm9p@4ax.com>,
Al Klein <rukbat@pern.invalid> wrote:
On Mon, 19 Mar 2007 22:53:44 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
New bird species found in Idaho
New finch species demonstrates the co-evolutionary arms race
Luddites will say "they're still birds" or "they're still finches".
I know. It's just "microevolution" to the ignoramuses.
They're still ignoramuses. :)
.
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| User: "johac" |
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| Title: Re: Bird speciation in Idaho? |
21 Mar 2007 05:32:22 PM |
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In article <7ga203hthhoi625l79mb5c2nbrbsmm014a@4ax.com>,
Al Klein <rukbat@pern.invalid> wrote:
On Tue, 20 Mar 2007 21:31:42 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
In article <g491035gm6i243r6ru76tinu1ira6enm9p@4ax.com>,
Al Klein <rukbat@pern.invalid> wrote:
On Mon, 19 Mar 2007 22:53:44 -0700, johac
<jhachmann@remove.sbcglobal.net> wrote:
New bird species found in Idaho
New finch species demonstrates the co-evolutionary arms race
Luddites will say "they're still birds" or "they're still finches".
I know. It's just "microevolution" to the ignoramuses.
They're still ignoramuses. :)
And as long as they believe in their imaginary friends, they will be.
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
.
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