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Sympatry, Allopatry, etc.

I searched a variety of online resources including dictionaries,
essentially easy to get ecological and evolutionary databases, and foudn
that the definitions for sympatry and so forth are in fact geographic
dependant on a populuations relation to another. Confusion was mine. Also
found defintions for parapatry where a population returns to its original
speciation point but it distinct from the parent population. Similarly,
_-patry_ is given as derived for "fatherland" from "father", or _pater_,
where _patr-_ is the compound form: one gets a "patronym" from one's
father, as much as from one's "fatherland", and I would suggest the use of
"fatherland" is variable with "father".

  Anyways, my gleaning is thus:

>From Botany Online

Sympatry: Phylogenetically closely related taxa living in the same area or
in overlapping areas are called sympatric. 

Allopatry: Phylogenetically closely related taxa living in different areas
are called allopatric. 

>From xrefer (http://www.xrefer.com/):

The occurrence of species in different geographic regions. When closely
related species are separated, differences between them that minimized
their competition for food, shelter, or other resources, usually decrease
(i.e. the characteristics converge). The process is called character
displacement and may be morphological or ecological.


The occurrence of species together in the same area. The differences
between closely related species usually increase (diverge) when they occur
together, in a process called character displacement, which may be
morphological or ecological.

>From Enchanted Learning Online (www.enchantedlearning.com/subjects/

Allopatric speciation is the formation of new species after a population
has been separated geographically. Over time, the two isolated populations
diverge genetically. Allopatric speciation is probably the major mode of
speciation (the formation of new species).


Sympatric speciation is the the formation of a new species within a
geographical area - it is probably caused by strong selection pressures.
Compare with parapatric speciation and allopatry.

also with

Parapatric speciation (the formation of new species) occurs when a
population enters a new habitat or niche within the same geographical area
of the parent species, but becomes reproductively isolated from the parent
species. Compare with allopatric speciation and sympatry.

>From Bartlby.com:

Ecology Occupying the same or overlapping geographic areas without
interbreeding. Used of populations of closely related species.


  David Marjanovic also made comments on how allopatry and sympatry would
be synonymous to some degree, but they are in fact mutually exclusive:

syn- + Greek patr, fatherland (from patr, patr-, father; see pter- in
Appendix I) + -ic.

and as a contrast:

allo- + Greek patr, fatherland (from patr, patr-, father; see pter- in
Appendix I) + -ic.

where syn- = together, or joined, and allo- = different, apart.

  Hence, *Allosaurus* is the "other lizard" or a "different lizard" from
*Ceratosaurus*, also it is "different" and morphologically "apart" from
the ceratosaurs, or in fact any other know theropod, because of the shape
of the vertebrae in the holotype.


  David also made comments on my use of sympatric speciation as being the
reason why my definition was different from his for "sympatry" but I was
under the impression we were discussing _evolution_. Both definitions are
apt, but geography is, in fact, the issue in the discussion of sympatry
and allopatry.


Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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