imported>RN1970: Undid revision 1218115144 by 2601:249:8801:4C20:144B:6AA:95B8:61DA (talk) -rv. not the same

2024-08-21T12:28:19Z

Undid revision 1218115144 by 2601:249:8801:4C20:144B:6AA:95B8:61DA (talk) -rv. not the same

New page

{{short description|Connections between subspecies}}
In [[zoology]], '''intergradation''' is the way in which two distinct [[subspecies]] are connected via areas where [[populations]] are found that have the characteristics of both. There are two types of intergradation: primary and secondary intergradation.

== Primary intergradation ==
This occurs in cases where two subspecies are connected via one or more intermediate populations, each of which is in turn intermediate to its adjacent populations and exhibits more or less the same amount of [[Genetic variability|variability]] as any other population within the [[species]]. Adjacent populations and subspecies are subject to [[Cline (population genetics)|cline]] intergradation, and in these situations it is usually taken for granted that the clines are causally related (by [[natural selection]]) to [[environmental gradient]]s.<ref name="M&A91">Mayr E, Ashlock PD (1991). ''Principles of Systematic Zoology''. Second edition. McGraw-Hill. {{ISBN|0-07-041144-1}}.</ref>

== Secondary intergradation ==
When contact between a geographically isolated subspecies is reestablished with the main body of the species or with another isolate subspecies, interbreeding takes place as long as the isolate has not yet evolved an effective set of isolating mechanisms. Consequently, a relatively distinct zone or belt of [[Hybrid (biology)|hybridization]] will develop depending on the degree of [[genetics|genetic]] and [[phenotypic]] difference that was achieved by the previously isolated [[subspecies]].<ref name="M&A91"/>

==See also==
* [[Ring species]]

==References==
{{Reflist}}

[[Category:Hybridisation (biology)]]
[[Category:Population genetics]]
[[Category:Evolutionary biology]]

Intergradation - Revision history

imported>RN1970: Undid revision 1218115144 by 2601:249:8801:4C20:144B:6AA:95B8:61DA (talk) -rv. not the same