Transcript Biogeography and Evolution - Botany Department

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
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
Buffon the Visionary
Georges Buffon (1761)
 Noted faunistic
differences and
similarities between
regions of similar climate
(“Buffon’s Law”)
Georges de Buffon ca. 1760
 Fossils, extinction,
changes in species,
climate and geography
Map of Artic from Histoire Naturelle
Continuing Exploration
 Humboldt (1805)
Plant zonation, associations
and biomes
Alexander von Humboldt
 Candolle (1820)
Coined term ‘endemic’
Defined ca. 20 regions of
endemism
Disjunctions: bipolar and
Africa-Austraila
Augustin Pyrame de Candolle
What are patterns of distribution
of species seen across the globe?
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.
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.
2.
3.
Regions with identical climate have different floras and
faunas (Buffon’s Law).
Geographic barriers closely associated with breaks
between taxonomic groups.
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
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
Erection of ocean
barrier
Divergence in
isolation
Widespread species
Continuous continental area
Dispersal
Disjunct (vicariad) species
Disjunct continental areas
Dispersal across ocean
barrier
Divergence in
isolation
Species limited to one area
Disjunct continental areas
Disjunct species
Disjunct continental areas
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
S ou the rn He m isph e re Te m pe rate Flora
35 species of trees and shrubs, evergreen and deciduous, restricted to South
Am erica, New Zealand, Australia, Tasm ania, 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
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