Tropical Ecology Spring 10 – climate & geological history 1
Geology and history of tropical biota
1. Animals move more than land moves (Darlington 1957, "Zoogeography")
2. Sahara has vast petrified logs and major (dry) river drainage systems indicating
much rain and lush forest in the past. Did climates change or did land move?
3. The tropical regions share few mammal families but many plant families.
II. Factors that have determine the present day distribution of organisms
1. Habitat today: physical setting - climate, soil
biotic setting - vegetation type, food availability, mutualistic
1. History: antiquity - the place of origin.
availability of dispersal routes (barriers, land bridges, water ways)
island effects (extinction)
III. Continental drift.
2. Wegener (1915) - matching shape of S. America and Africa.
3. Continent, epicontinental seas, continental shelf vs. deep ocean.
4. Earth's crust (= 70 km thick lithosphere) in which continents (ca. 25 km thick,
made of granite rocks) and ocean floor (5-8 km thick made of heavy gabrro and
basalt) sliding on the top of 70-250 km thick asthnosphere (1-10 % partially
molten dense rock).
5. Major land masses -- time course of their movement.
6. Type of changes - latitudinal, separations, later reunions.
Collision of continents: e.g., India.
Temporal land bridges due to lowering sea level during cold climates
Stepping stones: Antilles archipelago (80 my BP-)
IV. Geographical distribution of taxa.
1. Global distribution of plants and animal families.
2. Convergence and divergence between continents.
3. Wallace's line and biogeography of S. E. Asia.
4. Central American land bridge and the Great American Faunal Exchange.
Tropical Ecology Spring 10 – climate & geological history 2
A. Analysis of megathermal plant species.
Much insight comes from analysis of geological and fossil evidence, including microfossils. Morley (2000) analyzed the unpublished oil company stratigraphical analysis of fossil pollens, reconstructed waxing and waning of tropical forests, driven by the series of climatic pulsations.
Megathermal plant communities originally developed in three parallel belts separated by the subtropical high-pressure zones.
Northern belt: mid-altitude of N. America and Europe (Bombaceae)
Southern Belt: southern South America and eastern Gondwana (Proteaceae)
Megathermal pantropical plant families (Morley 2000, adopted from van Steenis 1957)
Annonaceae Dichapetalaceae Hippocrataceae Opiliaceae
Bombacaceae Dilleniaceae Lecythidaceae Pandanaceae
Burseraceae Dipterocarpaceae Malphigiaceae Rhizophoraceae
Cannaceae Erythroxylaceae Marantaceae Taccaceae
Cochlospermaceae Flagellariaceae Musaceae Tiuridaceae
Combretaceae Guttifarae Myristicaceae Zingiberaceae
Connaraceae Hernandiaceae Ochnaceae
B. Geological periods (numbers in millions of years ago, or Ma) ---------------------------------------------------------------------------------------------------------
Cenozoic Quaternary (3 - 0) Holocene post-glacier (11,000 BP-)
Pleistocene (3-0.5) early man. frequent glaciers
Tertiary (65 - ) Pliocene (13 - ) large carnivores
Miocene (25 - ) 1st common grazers
Oligocene (36 - ) large running mammals
Eocene (54 - ) many modern mammals
Paleocene (65 - ) 1st placental mammals
Mesozoic Cretaceous (135- )
Jurassic (180 - ) 1st birds & mammals
Triassic (230 -) 1st dinosaurs
Paleozoic Permian (280 - ) mass extinction
Carboniferous (310 - ) great coal forest, 1st reptiles
Devonian (395 -) first amphibians
Silurian (440 - ) first land plants
Ordovician (500 - ) earliest known fish
Cambrian (600 - ) marine invertebrates
Precambrian (3500 or more) first fossils
Tropical Ecology Spring 10 – climate & geological history 3
C. Major geological events that shaped tropical biota
245 Ma -- end of Permian (mass extinction - maybe as many as 99 % of all species) 200 Ma -- Pangea began to split--- dinosaurs evolved and speciated through 200-65 my
135 Ma -- Beginning of Crataceous. 2 super continents, Laurasia and Gondwana --
evolution of flowering plants since. Diversification of Angiosperm estabalished
110-90 Ma (but no tall & closed tropical forests with large mammal dispersed
100 Ma -- South America split from Africa
65 Ma – K-T mass extinction, marking the Cretaceous and dinosaur era. Beginning of the
adaptive radiation of mammals, large-seeded angiosperms and tall forest. ca. 50 Ma – early Ecocene thermal maximum – tropical rain forests as wide spread as far
as near 60? N and S.
36 Ma – the terminal Ecocene cooling –contraction of tropical forests, disappearance of
Northern and Southern belts of tropical forests.
16-10 Ma – middle Miocene warming and brief expansion of tropical rain forests. Pliocene (5 Ma – 1.6 Ma) ; low atmospheric CO prompted evolution of C grasses. 24
Cooler and drier climate expand.
6-3 Ma Formation of Central American land bridge
; Great American Faunal Interchange (GAFI).
3 Ma – 11,000 BP – cooling and repeated glacial episodes. Further contraction of
tropical forests due to cooling (Collinvaux et al. 1996), as well as savanna
expansion? (c.f., movement of Savanna animals during the Great American
Interchange, Webb 1996). Particularly severe reduction of tropical forests and
extinction of rain forest species in Africa.
11,000 yrs BP to current (Holocene) Re-expansion of tropical rain forest. Wide-spread
deforestation by humans. Increased fire incidences?
D. Summary of the Great American Faunal Interchange (Terborgh 1992)
N. America S. America
Number of mammal families (genera) before GAFI 30 (131) 35 (72)
Number of genera right after GAFI (101) (100)
Number of mammal families (genera) NOW. 33 (141) 35 (170)
Percentage of original families 64 % 60 %
Bottom line: Continental drifts do not explain distributions at all taxonomic levels (e.g., Simphonia blogulifera managed to disperse between S. Am and W. Af in mid-Mocene). Nevertheless, it explains sharing of Angiosperm families between continents and many disjunct and odd distributions of taxa (e.g., Nothofagus between Australia and Chile).
Tropical Ecology Spring 10 – climate & geological history 4
References for Continental drift, climate change and distribution of organisms.
Darlington, 1957. Zoogeography: the geographical distribution of animals. Harvard
University Press, Cambridge, Mass.
Dick, C. W., E. Bermingham, M. R. Lemes, and R. Gribel. 2007. Extreme long-distance
dispersal of the lowland tropical rainforest tree Ceiba pentandra L. (Malvaceae) in
Africa and the Neotropics. Molecular Ecology 16:3039-3049.
Dick, C. W., and M. Heuertz. 2008. The Complex Biogeographic History of a
Widespread Tropical Tree Species. Evolution 62:2760-2774.
Flenley, J. R., 1979. The equatorial rain forest: a geological history. Butterworths,
Head, J. J., J. I. Bloch, A. K. Hastings, J. R. Bourque, E. A. Cadena, F. A. Herrera, P. D.
Polly, and C. A. Jaramillo. 2009. Giant boid snake from the Palaeocene
neotropics reveals hotter past equatorial temperatures. Nature 457:715-U714.
Jaramillo, C., M. Rueda, and G. Mora. 2006. Cenozoic plant diversity in the Neotropics.
Mejia, P., D. Dilcher, and C. Jaramillo. 2006. Early angiosperm evolution in tropical
latitudes. Palynology 30:222-222.
Morley, R. J. 2000. Origin and evolution of tropical rain forests. Chichester, Wiley.
Ohsawa M. 1990. An interpretation of latitudinal patterns of forest limits in South and
East Asian mountains. Journal of Ecology 78: 326-339.
Raven, P. H. and Axelrod, D. I. 1974. Angiosperm biogeography and past continental
movements. Annals of the Missouri Botanical Garden 61: 539-61, 637-57. Richards, P. W. 1978. Africa, the “odd man out”. Pg. 21-26. In: Meggers, B. and Ayensu,
E. S., an Duckworth, W. D. (eds.) Tropical Forest Ecosystems in Africa and
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Rich, P. V. and Rich, T. H. 1983. The Central American dispersal route: biotic history
and paleogeography. Pg. 12-34. In: Janzen, D. H. (ed) Cost Rican Natural
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Terborgh, J. 1992. Diversity and the Tropical Rain Forest. Scientific American Library,
Webb, S. D. and Rancy, A. 1996. Late Cenozoic evolution of the Neotropical mammal
fauna. Pg. 335-358. In: Jackson, J. B. C., Budd, A. F. and Coates, A. G. (eds.)
Evolution and environment in tropical America. University of Chicago, Chicago. nd ed. Oxford University Whitmore, T. C. 1998. An introduction to tropical rain forests, 2
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Chszdon, R. L. and Whitmore, T. C. (eds.) Foundation of Tropical Forest Biology.
University of Chicago, Chicago.
Wolfe JA. 1978. A paleobotanical interpretation of tertiary climates in the northern
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Wolfe JA and Upchurch GR. 1986. Vegetation, climatic and floral changes at the
Cretaceous-Tertiary boundary. Nature 324: 148-152.