1. Summary from the last lectures
We have a reliable method for determining the age of rocks and fossils.
As a result we know:
The Earth and the solar system are 4.6 billion years old.
The oldest fossil organisms on Earth (bacteria) are 3.5 billion years old.
There is plenty of time for evolution
And the data do not support the hypothesis of Devine Creation of a 6,000 year old universe.

2. I believe this is the way the world is

3. Not this

4. I agree. And I have even more evidence
Alfred Russel Wallace

5. AND NOW Alfred Russel Wallace
Evidence From
Biogeography
AND NOW
Alfred Russel Wallace

6. Biogeography= the study of the distribution of organisms

7. Recall that one of Darwin’s clues about Evolution was that the distribution of animals did not meet his expectations if Creation were correct:
e.g. Fossil armadillos and living armadillos were in the same area of the world not distributed in different places. This suggested that Glyptodonts were the ancestors of current day armadillos.
I.e. Evolution had occurred
e.g. Individuals living close to one another in a given species more closely resembled each other than individuals living at a distance—this suggested that organisms close together are more closely related than those further away.
Further, that this variation if great enough would produce new species.
i.e. Evolution seemed the answer.

8. From Wallace’s 1876 book
The Geographical Distribution of Animals

9. How do we explain these distribution patterns?
Proteaceae family

10. Flying squirrel distribution

11. Cichlid fish distribution

12. Wolverine distribution

13. How do organisms get to where they are found?
Created (evolved) there.
Active Immigration: under their own power (walking, swimming, flying).
Passive immigration carried by water, air, or land movement.
a. floating rafts of debris.
b. birds carrying seeds
c. insects carried by air currents
d. tectonic plates
e. humans carrying domestic animals & plants
invasive species

14. Test: Look at distribution patterns of organisms
Deduction (Prediction)
If the Hypothesis of Creationism is correct then there was a single Center of Creation .
And places with similar environments should have similar organisms
Test: Look at distribution patterns
of organisms

15. Creationist argument: Biblical Flood led to recolonization of the world when organisms disembarked from Noah’s Ark

16. The conventional explanation that species had been created with adaptations to their particular climate made no sense to Wallace because he knew similar climatic regions had very different animals in them.
Instead, he found that closely related species were found together even though they might be in different habitats.

17. If the Hypothesis of Creationism is correct then places with similar environments should have similar organisms.
Linnaeus (1701—1778) Father of Taxonomy
Different species live in different areas
Buffon (1707—1788) French Naturalist
Mammals of Africa & South America are different.
Humboldt (1769—1859)
Plants of Africa & South America are different.

18. No species are alike in Africa & South America
Lattreille (1762—1833) French zoologist
Insects are different in Africa & South America
Cuvier (1769—1832) French Paleontologist
Reptiles are different in Africa & South America
No species are alike in Africa & South America
even though their climates are similar.
They are in distinct Biogeographic Zones

19. Biogeographic Zones

20. There is no single center for Creation
Evaluation:
Data do not support the hypothesis of Devine Creation.
There is no single center for Creation

21. Test: Look at distribution patterns of organisms
Deduction (Prediction)
If the Hypothesis of Evolution is correct then related species should live near one another
Or distribution patterns should be explained by the geological record—barriers and diffusion
Test: Look at distribution patterns
of organisms

22. Distance between related species
Data:
Darwin in South America found species living close together are more similar than those living farther apart. X X
Similarity
Index X X X X X X X X X X
Distance between related species

23. Real Data for Gastropods (Snails Etc.)

24. Patterns of Distribution
Cosmopolitan Distribution (found almost everywhere in the world)
Brown rat

25. Patterns of Distribution
Continuous Distribution (found spread over a large range. E.g. starlings over Europe and N. America

26. Patterns of Distribution
Continuous zonal distribution (found throughout certain climatic zones.
E.g. moose spread throughout the Northern latitudes

27. Patterns of Distribution
Endemic Distribution (highly restricted to one area)
e.g. lemurs are restricted to Madagascar

28. Patterns of Distribution
Discontinuous (= Disjunct) Distribution
(found in a few separated areas)
e.g. bog turtle

29. The challenge is to explain how a once continuous population became discontinuous. Two answers:
Dispersal—population spreads out to distant places—flying, swimming, carried by wind or water or animals.
Vicariance—population gets split up by continental drift, glaciers, mountain building, rivers, and the intervening populations become extinct.

30. Patterns of Distribution
Scattered Distribution (small local populations)
e.g. Bighorn sheep

31. History matters How can we explain these distributions?
The creation model doesn’t help us.
But the evolution model plus the geological record should help us.
History matters

32. Abiotic Factors What are the factors that determine distribution?
1. Physical factors (e.g temperature, light, soil, fire, currents)
Abiotic Factors
2. Chemical factors (e.g. water, oxygen, salinity, pH, soil nutrients)
3. Geographical & geological barriers to
dispersal (e.g. rivers, mountains, glaciers,
oceans)
4. Biological factors (e.g. predators, parasites, disease, competition, food.)

33. Patterns of interchange between biotic provinces.
Corridors = large areas where free migration can occur.
e.g. the animals of Western Europe , North China and North America are similar.

34. Land Bridges—Bering Strait
Asia
North America

35. Patterns of interchange between biotic provinces.
Filter bridge = an area of exchange between two areas that is restricted.
e.g. The Isthmus of Panama restricts movement between North and South America.
30—120 miles across
Formed 3 mya when South American continent collided with North America

36. Filter Land Bridges—Isthmus of Panama

37. Filter Land Bridges—Isthmus of Panama

38. Patterns of interchange between biotic provinces.
Sweepstakes Route = a route of exchange that is rare
Volcanic Islands are populated like this.
e.g. Galapagos Islands.
~600 miles from Ecuador
Animals and plants are like the mainland species

39. Island biogeography: Effect of distance from mainland
Bird species in the Lesser Antilles (D. Lack's data)

40. Species number and Island Area
Reptiles and Amphibians in the Caribbean Islands

41. So we can explain island biogeography on the basis of immigration into islands and extinction.
Immigration depends upon the distance from colonizing source (e.g. mainland). The more isolated the islands, the fewer species.
Extinction depends on the area available for speciation and niche specialization (The greater the island area, the more species can specialize and survive.)

42. Fragmentation of the environment producing islands
A big take a way message of this island study is that the smaller the island is, the fewer the species will survive.
As humans alter their environment with more houses, agricultural fields, parking lots and towns, they break up the environment into smaller and smaller parcels of land.
They fragment the environment into islands. And fewer and fewer species can exist.

43. How do we explain this? Mysterious case of Mesosaurus
Freshwater reptile living in lakes and steams.
One meter long.

44. Mysterious case of Mesosaurus.
Biogeography is forever seeking explanations of distributions using the principles of evolution, ecology, and geology.

45. Explained by continental drift !
Mysterious case of Mesosaurus
Vicariance
Explained by continental drift !

46. Continental
Drift

48. Continental
Drift

49. Plate Tectonics explains this

50. Flying squirrel distribution
Convergent evolution
explains this
Flying squirrel distribution

51. How do we explain this?

52. Wallace Line
A line separating the Asian and Australian biogeographic zones

53. The evidence from biogeography
Conclusion
There is no single center of distribution as you would expect with the Biblical Story of Creation.
The model of evolution can explain the patterns of distribution of organisms with the help of geology, ecology, evolution, and radiometric dating.
The evidence from biogeography
supports the model of
evoltuion

54. Next Time
Evidence from
Anatomy & Embryology