minimum viable area (MVA) The area needed
for maintaining the minimum viable population of
a species.
minimum viable metapopulation (MVM) The
minimum number of interacting local populations
needed for the long-term persistence of a species in
an area.
minimum viable population (MVP) The mini-
mum size of a population that will ensure its long-
term survival, for instance, providing a 95% of
persistence probability for the next 100 or
1000 years.
molecular clock Based on the idea that proteins
and DNA evolve at a more or less constant rate, the
extent of molecular divergence (attributable to ran-
dom mutations) is used as a metric for the timing of
events within lineage development: greater confi-
dence can be placed in such molecular clocks if they
can be independently calibrated.
monoecy Refers to plant species that have
separate male and female flowers on the same
individual.
monophyletic group A group of taxa that share a
common ancestor and which includes all descen-
dants of that ancestor, also referred to as a clade.
natural selection The process of eliminating from
a population through differential survival and
reproduction those individuals with inferior fitness.
naturalized species A non-native species that has
established a breeding population.
neoendemic A species exclusive to an area
(island or island group) that has evolved its
distinctive characteristics in situ, having originally
colonized from a continental ancestor (contrast
withpalaeoendemic).
nestedness Where a set of islands is ranked
according to species richness, the tendency for each
successively smaller assemblage to be a subset of
richer sets.
niche The total requirements of a population or a
species for resources and physical conditions.
niche expansion An increase in the range of habi-
tats or resources used by a population, which may
occur when a potential competitor is absent.
non-adaptive radiation A radiation process
driven not by natural selection, but rather by
genetic drift or sexual selection.
non-equilibrium A characteristic of communities
that change constantly in structure and composition
due to the vagaries of the environment and where
stable end-points are not achieved.
nuées ardentes Seepyroclastic flow
oceanic islands Islands originated from subma-
rine volcanic activity, mostly with basaltic founda-
tions, that have never been connected to the
continents. Initially populated by species that
have dispersed to the islands from elsewhere are
subsequently enriched by speciation.
palaeoendemic A species exclusive to an area
(island or island group) that has apparently
changed little since colonization, and which has
disappeared from its continental source area (con-
trast with neoendemic).
Pangaea The supercontinent, comprising all
present continents, which coalesced in the late
Carboniferous or early Permian and which broke
up some 70 million years later in the late Triassic.
panmictic population Population where mating
occurs randomly with respect to the distribution of
the genotypes in the population.
parallel evolution The evolution of similar or
identical features independently in unrelated
lineages.
parapatric speciation A mode of speciation in
which differentiation occurs when two populations
have contiguous but non-overlapping ranges, often
representing two different habitat types.
paraphyletic group An incomplete evolutionary
unit in which one or more descendants of a partic-
ular ancestor have been excluded from the group:
also referred to as a grade.
parthenogenesis The development of eggs with-
out fertilization by a male gamete.
peninsular effect The hypothesized tendency for
species richness to decrease along a gradient from
the axis to the most distal point of a peninsula.
phylogeny The evolutionary relationships
between an ancestor and all its known descen-
dants.
phylogeographical analysis The analysis of
geographically structured genetic signal within a
single taxon (e.g. species); the reconstructed
genealogical history is used to infer past episodes
of population expansion, bottlenecks, vicariance,GLOSSARY 347