Paleogeography Flashcards
biogeography
The science that attempts to understand spatial patterns of diversity. It is the distribution of organisms, both past and
present, and of related patterns of variation over the earth in the number and kinds of living things.
paleobiogeography
The analysis of biogeographic patterns in fossil taxa
Historical biogeography
the past distributions of organisms and how the evolutionary history of clades effects their present distribution
Ecological biogeography
explanations of the distributions of organisms based on ecological parameters (modern climatic and ecological features)
Fundamental questions of paleobiogeography
How are organisms distributed over the surface of the earth and over the history of the earth?
What controls these distributions?
Consistent surface airflows
prevailing winds
Radiation in land vs ocean
land-opaque
Ocean-penetrates
Heat capacity in land vs. oceans
Land-low ocean-high
Winds circulate _______ around high pressure cells in the Northern hemisphere.
clockwise
Summer relationship between oceans and land
Land warmer than oceans. Lower pressure in continents. Winds flow from the oceans to the land. This bring moisture into the continents.
Winter relationship between oceans and land
Oceans warmer than land. Lower pressure in the ocean. Winds blow from the land to the ocean, cold dry air flowing outward from the coast.
biomes
the world’s major communities, classified according to the
predominant vegetation and characterized by adaptations of organisms to that particular environment
Usually describe terrestrial, but can be aquatic
(ex-reefs, deserts, grasslands)
Warm periods of Earth’s history
Greenhouse
Cold Periods of Earth’s History
Ice house (glacial periods)
What was the climate like at the end of the mesozoic.
Warm climate. Climate has been cooling since the end of the Oligocene.
position of continents relative to poles -latitude and orientation
Paleomagnetism
Ways to decide where the continents were
\+Paleomagnetism \+Age of sea floor \+Climatic proxies \+Fossils \+Geologic "match up"
What could an unconformity tell you about what a continent looked like?
Might indicate that land was exposed at the time rocks were deposited.
What can metamorphic rocks tell you about what a continent looked like?
subduction and or plate collision; mountains
Ecological Biogeography
Explanations of the distributions of organisms based on interactions between organisms and their physical and biotic environments
Biogeographic regions
Communities across wide geographic regions are often quite similar, but can differ markedly from communities in another nearby region
provinces
regions over which communities maintain characteristic taxonomic composition
How do you define a province
Separated by geographic barrier that blocks
movement (mountains, oceans, continents)
Endemic provinces
confined to a single region or province; limited geographic range
Cosmopolitan provinces
multiple provinces; wide geographic range
Simpson Coefficient
Used to measure faunal similarity C/N*100 c=number of taxa in common n=total number of taxa in two samples.
Biogeographic regions on the scale of
continents or ocean basins – comprised of
similar provinces
Realm
Wallace’s Line
In indonesia Many fish, bird, and mammal groups are abundantly represented on one side of Wallace’s Line but poorly or not at all on the other side.
modern species diversity for many groups is highest in the tropics and decreases with higher latitude
Latitudinal Diversity Gradient
Tropics as cradle model
To explain latitudinal diversity gradient
origination rates are higher in tropical areas and extinction rates do not vary with latitude
‘Tropics as museum’ model
To explain latitudinal diversity gradient.
whereby origination rates are constant with latitude, but extinction rates are lower in the tropics
‘Out of the tropics’ model
To explain latitudinal diversity gradient
origination rates are higher and extinction rates are lower in tropical areas, and species movement is higher from the tropics to the extratropical areas
Has the latitude diversity gradient been a persistent feature throughout time?
No. Modern pattern thought to have originated 30 million years ago. (A tropical diversity peak might characterize icehouse worlds.)
number of species _____as geographic area increases.
increases
Historical Biogeography
Reconstruct origin, dispersal, and extinction of taxa and biotas
The past distributions of organisms and how the evolutionary history of clades effects their present distribution
Dispersal biogeography
Distribution of organisms due to dispersal (moving away) from a point of origin
(Can be moved through “noah’s ark”, sweepstakes, filter bridge, corridor)
North and South America united across Isthmus of Panama
~3.5 ma Faunal exchange between provinces
Great American Interchange
Vicariance biogeography
Distribution of organisms due to fragmentation of
a previously large geographic range
