Glossary - Evolutionary Biogeography - page 321

individual track primary spatial coordinates of a species or supraspecific taxon. It
is a line graph drawn on a map that connects the different localities or distri-
butional areas of the taxon according to their geographic proximity. From the
topological viewpoint, an individual track is a minimum-spanning tree that for
n localities contains n - 1 connections.
integrative biogeography combination of ecological and evolutionary biogeo-
graphy into a single general approach.
intraspecific phylogeography study of the principles and processes governing
the geographic distribution of genealogical lineages, especially those within
and between closely related species, based on molecular data.
items of error number of nodes and areas that are necessary to add to a tax-
on-area cladogram so that it agrees with the general area cladogram, that is,
to map one cladogram onto the other to determine their congruence.
jump dispersal random movement of organisms through barriers, which allows
successful establishment of the species in very distant areas. It is also known
as long-distance dispersal, waif dispersal, founder effect dispersal, or random
dispersal.
Laurasia supercontinent that included the northern landmasses. From the Jurassic
totheCretaceous,itwaspenetratedbyepicontinentalseas.IntheLateCreta-
ceous, Europe and Asia were separated by the Obisk Sea; the former was
connected to eastern North America (Euramerica), and the latter was connec-
ted to western North America (Asiamerica).
main massing greatest concentration of numerical, genetic, or morphological di-
versity within the range of a taxon, which can be used to orient an individual
track.
minimum-spanning tree method a method of delineating in maps the individual
tracks of different taxa and then superimposing them in order to find the gen-
eralized tracks. Nodes are identified in the areas where two or more general-
ized tracks superimpose.
missing areas when no terminal taxon is distributed in one of the areas analyzed,
this area will not be represented in the taxon-area cladogram.
modified Brooks parsimony analysis variation of Brooks parsimony analysis, de-
signed to deal with geodispersal, which involves two separate steps: retriev-
ing congruent episodes of vicariance and retrieving congruent episodes of
geodispersal.
molecular clock the assumption that the rate of molecular evolution is approx-
imately constant over time for proteins in all lineages, allowing inference of
a clock-like accumulation of molecular changes. The “ticks” of the molecular
clock, which correspond to mutations, occur not at regular intervals but rather
at random points in time. This time is measured in arbitrary units and then
calibrated in millions of years by reference to the fossil record or geological
data, giving minimum estimates of the age of a clade, which in turn may help
elucidate the relative minimum ages of the cenocron to which it belongs.