1. Study of distribution of organisms
Biogeography
Study of distribution of organisms

2. Biogeography
Comparative observational science
Experiments – limited utility
Multiple scales
Comparative has uses, though
Synthetic science

3. Subjects Used in Biogeography
Anatomy
Physiology
Taxonomy
Developmental
Evolution
Geology
Geography
Ecology
Climatology, Paleontology……

4. Relevance of Biogeography
What enables a species to live where it doe, and what prevents it from colonizing other areas?
What are a species closest relatives and where can they be found? Where did its ancestors live?
How have historical events shaped a species’ distribution?

5. Overarching question: What shapes global patterns of biodiversity?

6. The Importance of Time
Historical biogeography
Ecological biogeography
Paleoecology

7. “While the process of science owes much to admirable human traits……
“While the process of science owes much to admirable human traits……..it is also retarded by characteristics such as prejudice, jealousy, short-sightedness, and stupidity.”

8. History of Biogeography
Roots from questions that developed during the “Age of Exploration”
Shares common lineage with ecology
Early questions
From where did life come?
How did it diversify across the planet?

9. Persistent Themes in Biogeography
Classifying geographic regions based on their biota
Reconstructing historical development or lineages and biota, including their origin, spread, and diversification
Explaining differences in numbers and types of species among geographic areas, and along geographic gradients
Explaining geographic variation in characteristics of individuals and populations of closely related species

10. Age of Exploration
250 yr ago, only 1% of species known today identified
Mission – reveal mysteries of creation by learning of the diversity of life
Prevailing view – stasis
With increasing identification of species, was a clear need for organization

11. Carolus Linneaus (1707 – 1778)
Understanding organization would lead to knowing Creator’s plan
Took static view of Earth
Explain origin and spread of life
Challenge was to explain diversity and distribution

12. Carolus Linneaus (1707 – 1778)
How could life have spread from Paradise then landing spot of the Ark
Linnaeus – “Paradisical Mountain” – a mountain island life along the slopes, perfectly adapted for biotic and abiotic conditions at their “station”
Based on known conditions of tropical mountains
Later formation of land allowed spread

13. Comte de Buffon (1707 – 1788) Contemporary of Linaeus
Disagreed with his view of spread of life (living and fossil specimens)
Places with same climate had different species
Inhospitable environment around Mount Ararat
Proposed origin in northern Europe

14. Buffon’s hypothesis – climate was cooler at time allowing species to move to new areas and change
Key points – climate and species were dynamic (central to modern biogeographic theory and precursor to development of evolutionary theory)

15. Comte de Buffon (1707 – 1788)
Buffon’s Law – Environmentally similar but separated regions have different species of birds and mammals
Considered first principle of biogeography
Later studies by Joseph Banks and Johann Forster found Buffon’s Law applied to plants

16. Phytogeography
End of 18th century – natural theology still primary biological theory
Willdenow ( ) and Humboldt ( ) – phytogeography – geographic distribution of plants
Studies of plant distribution on Andes mountain (5,600 m elevation
Mt. Chimbaruzo

17. Phytogeography Identified floristic belts from tropical to arctic
Observed plant communities closely associated with local climate
Hints at competition (Candolle)
Mt. Chimbaruzo

18. Biogeography of 19th Century
First three themes established
Classifying geographic regions based on their biota
Reconstructing historical development or lineages and biota, including their origin, spread, and diversification
Explaining differences in numbers and types of species among geographic areas, and along geographic gradients

19. Biogeography of 19th Century
Buffon’s Law
Early biogeographers tested
Classify regions based on biota (theme 1)
Reconstructing origin and spread of life (theme 2)
Changes along gradients (theme 3)
Established approachs still used
Perception of static earth and life to dynamic

20. WHY?????? Number of local species increased with area
Limitations
Number of local species increased with area
Number of species decreased from equator
Needed to move to next step (rigorous testing) but first needed
WHY??????

21. Needs for Better Understanding
Better estimate of age of Earth (natural theology and 6,000 yr)
Understanding of dynamic nature of continents and oceans
Understanding of spread and diversification – dispersal, vicariance, extinction, evolution)

22. Early Advances of 19th Century
Borngniart – father of paleobotany
Lyell – father of geology
Both used fossil record to conclude climate changes over time (life forms of tropical climates in northern Europe
Lyell – changes in sea level and the lifting and erosion of mountains; extinction
New species arose through new creations after extinctions; new species created for new climate

23. Early Advances of 19th Century
Lyell proposed uniformitarianism
Also, realization that processes occur slowly (gradualism)
Time needed for geological processes + continual replacement of biota = Earth much older than 6,000 years

24. Four British Scientists
Charles Darwin, Joseph Hooker, Philip Sclater, Alfred Russell Wallace
Naturalists, traveling the world and discovering diversity
Shared their observations, building a broader image of life
Did not agree on all points

25. Darwin
Origin of Species – contribution is obvious
Proposed ideas on dispersal of life (countering Agassiz’s view of point near creation)
The “dispersalist” view made dispersal dynamic
Disagreement then moved to mechanisms of dispersal (dispersalists vs. extensionists)

26. Extensionists &
Land Bridges

27. Further Contributions
Hooker – study of southern hemisphere plant distributions lead to development of vicariance biogeography
Sclater – used distribution of passerine (perching) birds to develop a system of six biogeographic regions still used today
Also developed zones based on marine mammals (Fig. 2.8)

29. Wallace
Greatest contributions to biogeography (father of zoogeography)
Expanded view provided by Sclater’s zones
Established many of the basic principles of biogeography (see Box 2.1)
Observed a distinct change in fauna of Southeast Asia and Australasia (Wallace Line)

31. Other 19th Century Contributions
Bergmann’s rule – homeotherms, body size, and surface-to-volume ratio from poles
Allen’s rule – limbs of birds and mammals become shorter and stouter as move from equator.
Cope’s rule – groups tend to increase in size during their evolution
Limitation of generalities but open new thoughts
Cope’s tend to go to extinction but replaced by taxa that begin to increase

32. Other 19th Century Contributions
Merriam’s life zones
Study of elevational changes – found vegetation types and species composition are similar to longitudinal patterns
Confirmed Humboldt’s work
Cope’s tend to go to extinction but replaced by taxa that begin to increase

35. Burdgeoning info from paleontology
Twentieth Century
Burdgeoning info from paleontology
Origin, dispersal, radiation, and decline of terrestrial vertebrates
Development of phylogenies
New groups rise
Increase in number of species
Radiate to fill niches and expand range
Still – question of how dispersed
Cope’s tend to go to extinction but replaced by taxa that begin to increase

36. Patterns of morphological variation Coincided with Modern Synthesis
Twentieth Century
Relationships between geological and ecological properties of environment
Patterns of morphological variation
Coincided with Modern Synthesis
Linking lead to formulation of biological species concept (Ernst Mayr)
Also identified allopatric speciation
Cope’s tend to go to extinction but replaced by taxa that begin to increase

37. Earth’s crust believed fixed until 1960s
Continental Drift
Earth’s crust believed fixed until 1960s
Continental drift 1st proposed 1858
Resurfaced by Wegener and Taylor using geological and ecological evidence
Criticized and denied until evidence became overwhelming
Changed dispersal from land bridges to movements of continents
Cope’s tend to go to extinction but replaced by taxa that begin to increase

38. New Phylogenetic Methods
Continental drift lead to study of disjunctions
Vicariance biogeography
Examination and revision of phylogenies
Cope’s tend to go to extinction but replaced by taxa that begin to increase

39. Geographic information systems Geostatistics
Further Aids
Computers
Geographic information systems
Geostatistics
Cope’s tend to go to extinction but replaced by taxa that begin to increase