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Patricity is a newly created term that describes the degree by which the ranges of two sets of organisms overlap. Patricity embraces the terms allopatry, peripatry, parapatry, and sympatry that signify different degrees of patricity. The degree of patricity respectively increases in the given order.

Current terminology


Allopatry is an ecological and biogeological term that signifies that groups of organisms live in separate not overlapping geographical areas. For instance, two populations of the same species living on different island are allopatric. Allopatry is the opposite of sympatry.


Peripatry is a term from ecology and biogeography that describes the relationship between groups of organisms whose ranges are adjacent but not overlapping. For instance, two plants are peripatric if they grow on opposite river banks or separated by a mountain ridge.


Parapatry is a term from ecology or biogeography that describes the relationship between groups of organisms whose ranges are adjacent but not significantly overlapping. Two plant species are parapatric if they grow on adjacent grounds but different soil.


Sympatry, is a term from ecology and biogeography that constitutes the same or significantly overlapping distributions of different sets of organisms. We call two species sympatric if they inhabit the same geological area. Two animals living ins the same forest are sympatric, for instance. Sympatry is the opposite of allopatry.


Continuous vs. discontinuous patricity

These various definitions of subtypes of patricity that evolved by the progress of ecology and biogeography already signal that there is much controversy about the degree of overlap. This controversy can only be solved by accepting a continuum and defining a gradual measure of overlap.

For instance take two separate island that constitute a typical case of allopatry. It is quite unlikely but still possible that a bird or a seed reaches the other island. At an archipelago this seem to be not uncommon, but the farer the island the less the probability of exchange between them. But it still happens even on remote islands as we learned from vegetations whose seeds thousands of kilometers. Therefore even typical allopatric habitats show some degree of sympatry.

As it is difficult to exclude sympatry from typical allopatric habitats, the degree of patricity is even more disputable in para- and peripatric ones. There are virtually no two paparatric habitats on this planet that show exactly the same degree of patricity.

Gradual patricity along geographical gradients

The fact that no two habitats show the same patricity is even more true because patricity itself is time dependent and changes gradually with the geographical area.

The typical cases of time dependence are ecological changes caused by the El Niño and other periodic climate changes. Geographical changes can be observed on mountain slopes where temperature dependent differences in pollination and flowering times exert reproductive isolation. The same holds true with different water depths and soil also changes gradually.

Geographically independent patricity

Apart from time dependent climate changes and gradually changing environments there are other, biological factors that affect patricity. For instance behavioral patterns as bird songs and the avaulability of food and the thread of predators.

Overlapping patricities

In summary there is a network of intertwined ever changing patricithies that affect an individiulas behaviour in a statistical manner. Some more and some less prominent

Fauceir patricity

Definition in fauceir terms


The most common use of patricity is in connection with speciation. In which the degree of patricity is equivalent to the degree of gene (allele) flow, which can be measured statistically. As the fauceir concept does not focus on genes alone. Widening the perspective and including all kinds of fauceirs, patricity can be measured by the exchange of element fauceirs, which also can be measured statistically.

Tags: Biogeology Ecology Evolution


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