Biogeography – the study of organismal distribution in evolutionary, phylogenetic, or ecological contexts Current organismal distributions result from both evolutionary history and contemporary ecology
Biogeography
– the study of organismal distribution in
evolutionary, phylogenetic, or ecological
contexts
Current organismal distributions result from
both evolutionary history and contemporary
ecology
Biogeographic Realms of the World (differences exist among authors)
http://biology.clc.uc.edu/courses/bio303/terrest_habitats.htm
Definitions
Indigenous – native to an area
Endemic – unique to an area
Sympatric – overlapping geographic distribution (i.e,
two species living in the same place)
Parapatric – contiguous but non-overlapping
geographic distribution
Allopatric – non-overlapping geographic distribution
Disjunct endemism – nearest relatives in allopatry,
typically separated by a geophysical barrier
alternative hypotheses to account for disjunct
endemism:
Vicariance – barrier divides originally contiguous
population into two or more
Dispersal – organisms overcome barrier (either
actively or passively) to establish new population
Organismal distributions result from both
contemporary ecology and evolutionary
history
Ecological factors:
Resource availability, competitors, abiotic
factors (e.g., climate), environmental
heterogeneity
Similar patterns of diversification in
different locations (e.g., community
convergence or parallel radiations) is
evidence of common ecological factors
Historical processes:
Phylogeny, vicariance, dispersal, extinction
Similar phylogenetic topologies among
unrelated clades is evidence of common
causes of vicariance or modes of dispersal
Snapping shrimp (Alpheidae) - vicariance
Hawaiian Pohutukawa (Metrosideros) - dispersal
Percy et al 2008 Proc. R. Soc. B (2008) 275, 1479–1490
Dias dos Santos 2011 Pap. Avulsos Zool. 51
Vicariance and Dispersal
Models of Gene Flow
Island model – equal probability of flow
Stepping stone model – ordered
probability
Isolation by distance model – probability
inversely proportional to distance
Extinction and recolonization model –
stochastic replacement
Species Diversity
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nearby island
MacArthur and Wilson’s model of Island Biogeography
Species Diversity
Rat
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Colo
niz
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n R
ate of E
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ction
distant island
MacArthur and Wilson’s model of Island Biogeography
Species Diversity
Rat
e of
Colo
niz
atio
n R
ate of E
xtin
ction
small island
MacArthur and Wilson’s model of Island Biogeography
Species Diversity
Rat
e of
Colo
niz
atio
n R
ate of E
xtin
ction
big island
MacArthur and Wilson’s model of Island Biogeography
Species Diversity
Rat
e of
Colo
niz
atio
n R
ate of E
xtin
ction
nearby island
distant island big island
small island
MacArthur and Wilson’s model of Island Biogeography
Community Convergence Parallelism in Theria:
Marsupials and Placentals
“Ecomorphs” of Carribean Anoles