lecture 7 - biostratigraphy - paleobiology Flashcards
will be used for field trip (14 cards)
What is biostratigraphy?
The use of fossils to determine the relative age of rock layers and correlate strata across distances. Pioneered by William Smith (1769–1839).
Define FAD and LAD.
FAD (First Appearance Datum): First occurrence of a fossil (evolution/immigration).
LAD (Last Appearance Datum): Last occurrence (extinction/emigration).
List the four main types of biostratigraphic zones.
Concurrent Range Zone: Overlap of two taxa’s ranges.
Taxon Range Zone: FAD to LAD of one taxon.
Lineage Zone: Evolutionary transitions in a lineage.
Interval Zone: Between two FADs/LADs of unrelated taxa.
What makes a good index fossil?
Distinctive, widespread, abundant, short-lived, and facies-independent.
Examples: Ammonites, conodonts, graptolites.
What are Lazarus, Elvis, and Zombie taxa?
Lazarus: Temporarily “disappear” (e.g., due to habitat loss).
Elvis: New species misidentified as extinct ones.
Zombie: Fossils reworked into younger rocks.
What is graphic correlation (Shaw plots)?
A method to compare fossil ranges across sections, revealing differences in sedimentation rates or gaps.
Contrast ecological and historical biogeography.
Ecological: Current distributions (climate, habitats).
Historical: Past distributions (plate tectonics, evolution).
Name the major terrestrial faunal provinces.
Nearctic, Palearctic, Neotropical, Ethiopian, Oriental, Australian.
How are marine provinces divided?
By latitude/temperature (e.g., polar vs. tropical plankton).
What is vicariance?
Species distributions split by geographic barriers (e.g., mountain ranges, seas). Tested via congruent cladograms.
How do exotic terranes affect biogeography?
Accreted landmasses carry fossils from unrelated regions (e.g., western North America’s Mesozoic terraces).
What is the “Noah’s Ark” model?
A continent (e.g., India) carries fauna while drifting, then collides with another landmass.
Why is habitat fragmentation problematic?
Smaller habitats reduce diversity due to edge effects and isolation.
What factors control fossil presence/absence in strata?
Evolution, migration, extinction, erosion, nondeposition.
