Leith Nye and Rachel Schmidt
February 28, 2006

“ the study of what organisms live where on earth and why”
(from Humphries and Parenti, 1999)

Carolus Linnaeus (1707–1778)

Bible (AD):
 Young Earth
 Single creation of perfect species
 Origin: Mt. Ararat, Turkey where Ark landed
Possible remains of Noah’s Ark, Mt. Ararat
Linnaeus (1735):
 Notes variation in form
 Mountainous island center of origin theory
Linnaeus’s Mountainous Island Post Flood

Georges Buffon (1761)
 Noted faunistic differences and similarities between regions of similar climate
(“Buffon’s Law”)
 Fossils, extinction, changes in species, climate and geography
Georges de Buffon ca. 1760
Map of Artic from Histoire Naturelle

Continuing Exploration
 Humboldt (1805)
Plant zonation, associations and biomes
 Candolle (1820)
Coined term ‘endemic’
Defined ca. 20 regions of endemism
Disjunctions: bipolar and
Africa-Austraila
Alexander von Humboldt
Augustin Pyrame de Candolle

 Geographical regions have characteristic biotas.
 Similar/closely related taxa tend to be closer together than more distantly related groups.
 Similar environments are found in different areas BUT the same species may not be found in all places where they could be!
 Not closely related species in similar environments may appear similar due to convergence.

World’s Biomes

Distinct Faunas across Similar
Environments
Wallace’s Faunal Regions

Distinct Floras across Similar Environments
Good’s Floristic Regions

“In considering the distribution of organic beings over the face of the globe, the first great fact that strikes us is, that neither the similarity nor the dissimilarity of the inhabitants of various regions can be wholly accounted for by climatal and other physical conditions.”
Charles Darwin, The Origin of Species
A reasonable nonevolutionary prediction is that species should occur wherever their habitat is. However, macroevolution predicts just the opposite — there should be many locations where a given species would thrive yet is not found there, due to geographical barriers.
Futuyma, D. (1998) Evolutionary Biology . Third edition. Sunderland, Mass., Sinauer
Associates

Evidence: Geographical Distribution I and II
1.
Regions with identical climate have different floras and faunas (Buffon’s Law).
2.
Geographic barriers closely associated with breaks between taxonomic groups.
3.
Within a region, organisms are often closely related even across environmental gradients and lower taxonomic groups often show narrower distributions than higher.

Cactaceae in North American deserts
Euphorbiaceae in southern African deserts
Courtesy of K.J. Sytsma

Geographic Barriers and Distinct Biota
More similar marine biota
Very different marine biota

3. Closely Related Taxa in Close Proximity
Wallace’s Line

Disjunctions: A Bur in Darwin’s Saddle
Darwin goes to great pains to show how disjunct patterns of species distributions can be explained through climate changes, geological changes and dispersal.
Examples:
1.
Same alpine species on mountains between and across continents result of cycles of glaciation and migration.
2.
Similarity of freshwater fish species across continents due to flooding, twisters, birds, salt water tolerance etc.
3.
Islands biota can be explained by dispersal and previous existence of now submerged island chains.

Vicariance vs. Dispersal similar pattern, different process
Vicariance
Ere ction of oce an barrie r
W ide spre ad spe cie s
C ontinuous contine ntal are a
Dive rge nce in isolation
Disjunct (vicariad) spe cie s
Disjunct contine ntal are as
Dispersal
Dispe rsal across oce an barrie r
Spe cie s lim ite d to one are a
Disjunct contine ntal are as
Dive rge nce in isolation
Disjunct spe cie s
Disjunct contine ntal are as
Courtesy of K.J. Sytsma

Islands- Hawaii vs. Madagascar
“He who admits the doctrine of creation of each separate species, will have to admit that a sufficient number of the best adapted plants and animals were not created for oceanic islands, for man has unintentionally stocked them far more fully and perfectly than did nature.”
-Darwin, The Origin of Species
Courtesy of K.J. Sytsma

Vicariance Theory Lacking Mechanism
“Other authors have thus hypothetically bridged over every ocean and united almost every island with some mainland. If indeed the arguments used by
Forbes are to be trusted, it must be admitted that scarcely a single island exists which has not recently been united to some continent. This view cuts the Gordian knot of the dispersal of the same species to the most distant points , and removes many a difficulty; but to the best of my judgement we are not authorized in admitting such enormous geographical changes within the period of existing species.”
Darwin, 1859
Courtesy of K.J. Sytsma

Plate Tectonics…Enter Alfred Wegener
Wegener relied heavily on biogeographical evidence for defending his controversial continental drift theory
Glossopteris Permian
– “fern”
Mesosaurus
– Freshwater Permian Reptile
Cynognathus
– Triassic land reptile
Lystrosaurus
– Triassic land reptile
Courtesy of K.J. Sytsma

Southern Hemisphere Temperate Flora
35 species of trees and shrubs, evergreen and deciduous, restricted to South
America, New Zealand, Australia, Tasmania, New Caledonia, New Guinea, and fossilized in Antarctica
Absent from Africa! — “odd continent out”
Nothofagaceae
????
Courtesy of K.J. Sytsma

Three major patterns of dispersal/vicariance modality can be identified: 1) Cretaceous dispersal to Madagascar with ensuing distributions from India (and/or South Africa) across Antarctica to
South America and Australo-E. Malesia during the time of the initial radiation of the angiosperms; 2) Eocene-Oligocene (and continuing to the present) dispersal to Madagascar
(and Africa) from Laurasia and W. Malesia via India (pre- and post-collision with Asia) along
"Lemurian Stepping-stones" in the western Indian Ocean; and 3) continuous (and recent) long distance dispersal (LDD) to Madagascar as a function of the prevailing easterly winds and
Indian Ocean currents.
-G.E. Schatz, Malagasy/Indo-australomalesian Phytogeographic Connections

Species and Areas: History of Ideas
Two important scientific advances in the mid 20th century have revolutionized historical biogeography
1. Acceptance of plate tectonics
Up until the 1960s, most persons considered the earth's crust to be fixed. Finally, in the
1960s the geological evidence was at hand that made continental drift irrefutable.
2. Development of new phylogenetic methods
Willi Hennig (1950) introduced the modern concepts of phylogenetic theory (first published in 1956). Using this methodology, hypotheses of historical lineages of species could be reconstructed.
Courtesy of K.J. Sytsma

“We see in these facts some deep organic bond, throughout space and time, over the same areas of land and water, independently of physical conditions. The naturalist must be dull who is not led to inquire what that bond is . . . The bond is simple inheritance.”
Darwin, The Origin of Species

References:
Cox, B.C. and P.D. Moore. 2005. Biogeography: An Ecological and Evolutionary Approach . Blackwell Publishing,
Malden, MA, USA.
Darwin, C. 1859. The Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the
Struggle for Life . John Murray, London, UK.
Humphries, C.J. and L.R. Parenti. 1999. Cladistic Biogeography: Interpreting Patterns of Plant and Animal
Distributions . Oxford University Press, Oxford, UK.
Johnson, W.E. et al. 2006. The late Miocene radiation of modern Felidae: A genetic assessment. Science 311 :73-77.
Knox, E.B. and J.D. Palmer. 1995. Chloroplast DNA variation and the recent radiation of the giant senecios
(Asteraceae) on tall mountains of eastern Africa. Proc. Natl. Acad. Sci. 92 : 10349-1-353.
Lomolino, M.V., D.F. Sax and J.H. Brown, editors. 2004. Foundations in Biogeography . The Unversity of Chicago
Press, Chicago, IL, USA.
Wegener, A. 1915. Die Enstehung der Kontinente und Ozeane . Sammlung Vieweg und Sohn, Braunschweig.
Whitfield,J. 2005. Biogeography: Is everything everywhere? Science 310 :960-961.
International Institute for Aerospace Survey and Earth Sciences, Gondwana Animation: http://www.kartografie.nl/gondwana/index.asp