Biogeography and Evolution

Leith Nye and Rachel Schmidt

February 28, 2006

Biogeography

“ the study of what organisms live where on earth and why”

(from Humphries and Parenti, 1999)

A naturalist in Europe…

Carolus Linnaeus (1707–1778)

From the Ark to Ararat

Bible (AD): Young Earth Single creation of perfect

species Origin: Mt. Ararat, Turkey

where Ark landed

Linnaeus (1735): Notes variation in form Mountainous island center of

origin theory

Possible remains of Noah’s Ark, Mt. Ararat

Linnaeus’s Mountainous Island Post Flood

Buffon the Visionary

Georges Buffon (1761)

Noted faunistic differences and similarities between regions of similar climate (“Buffon’s Law”)

Fossils, extinction, changes in species, climate and geography

Map of Artic from Histoire Naturelle

Georges de Buffon ca. 1760

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

Augustin Pyrame de Candolle

Alexander von Humboldt

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.

What are patterns of distribution of species seen across the globe?

How else might we explain this distribution without biogeography principles??

What distributions would we expect to see WITHOUT macroevolution??

World’s Biomes

What broad distribution patterns do we actually see?

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

The Origin of Species

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.

1. Similar Climate, Different Taxa

Cactaceae in North American deserts

Courtesy of K.J. Sytsma

Euphorbiaceae in southern African deserts

Geographic Barriers and Distinct Biota

Very different marine biota

More similar 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. Dispersalsimilar pattern, different process

Disjunct (vicariad) speciesDisjunct continental areas

Disjunct speciesDisjunct continental areas

Species limited to one areaDisjunct continental areas

Dispersal across ocean barrier

Divergence inisolation

Widespread speciesContinuous continental area

Erection of ocean barrier

Divergence inisolation

Vicariance

Dispersal

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 SouthAmerica, New Zealand, Australia, Tasmania, New Caledonia, New Guinea,and fossilized in Antarctica

Nothofagaceae

????

Absent from Africa! — “odd continent out”

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

1. Acceptance of plate tectonicsUp 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.

Two important scientific advances in the mid 20th century have revolutionized historical biogeography

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

What is the ID/creationist response to biogeography?

“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