Geography Reference
In-Depth Information
refuge theory hypothesis developed by Jürgen Haffer to explain the biogeographic
patterns of the Amazon forest, which postulates that during the glacial periods
of the Northern Hemisphere, some centers of endemism were islands of rain
forestsurroundedbyaseaofgrasslands,allowingmanyforestspeciestosur-
vive therein and eventually evolve in isolation as separate species.
region biogeographic category intermediate between realm and dominion. The
biota of the world is classified into twelve regions: Nearctic and Palearctic
(Holarcticrealm);Neotropical, Afrotropical orEthiopian, Oriental, andAustrali-
an Tropical (Holotropical realm); and Andean, Antarctic, Cape or Afrotemper-
ate, Neoguinean, Australian Temperate, and Neozelandic (Austral realm).
regionalization biogeographic classification based on successively nested biotic
components. It takes place before cenocrons are elucidated and a geobiotic
scenario is proposed.
resolved area cladogram taxonomic cladogram in which widespread taxa, re-
dundant distributions, and missing areas are resolved before generalized
tracks are obtained. Also known as areagram.
retrodiction “prediction” of past events.
scientific research program basic unit of scientific investigation. It consists of
three parts the hard core, a set of assumptions that define the program, which
are irrefutable and which scientists protect as part of their research tradition;
the positive heuristic, a set of methodological rules that specify the research
policyoftheadherentsoftheresearchprogram;andtheprotectivebelt,aflex-
ible set of auxiliary hypotheses that are constructed, readjusted, or discarded
as directed by the positive heuristic. Research programs are progressive if
each modification leads to novel predictions, which are confirmed by subse-
quent research or by the chance discovery of new facts; they are degenerat-
ing if they are characterized by ad hoc modifications or by the persistent fail-
ure of their predictions to be corroborated empirically.
secondary biogeographic homology cladistic test of the biotic components.
secondary Brooks parsimony analysis variation of Brooks parsimony analysis in
which areas involved in parallelisms in the general area cladogram are duplic-
ated and dealt with separately to determine whether they were a unique area
or whether they were different areas incorrectly treated as a single one.
secular migration movement involving a short distance that occurs so slowly that
the species evolves in the meantime.
sweepstake route area completely surrounded by totally different environments,
such as islands, caves, or high mountain peaks, where chances of dispersal
areverylowformosttaxa.Theydifferfromfiltersinkind,notmerelyindegree,
because almost all the species that traverse them cannot survive.
systematic biogeography subdiscipline that describes, compares, and classifies
biotas.
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