lecture 1 - the fossil record Flashcards
(12 cards)
What are the four main divisions of geologic time (from largest to smallest)?
Eon, Era, Period, Epoch.
What are the three eras of the Phanerozoic Eon?
Paleozoic, Mesozoic, Cenozoic.
How do “Early/Middle/Late” (time) differ from “Lower/Middle/Upper” (rock)?
Time: Early/Middle/Late (e.g., Late Jurassic).
Rock: Lower/Middle/Upper (e.g., Upper Jurassic strata).
Define “fossil” and its Latin root.
Physical remains/traces of organisms preserved in rock; from Latin fossilis (“dug up”).
Contrast body fossils and trace fossils with examples.
Body: Shells, bones (e.g., dinosaur skeleton).
Trace: Tracks, burrows (e.g., trilobite tracks).
What two conditions favor fossilization?
Rapid burial + presence of hard parts (shells, bones).
Which bones are most/least likely to fossilize?
Group I (easily destroyed): Ribs, vertebrae.
Group III (most durable): Skull, lower jaw.
Give an example of unaltered hard-part preservation.
Cenozoic mollusk shells (original calcium carbonate).
List 6 types of altered preservation with examples.
Permineralization: Dinosaur bones (pores filled).
Carbonization: Plant films (carbon residue).
Recrystallization: Aragonite → calcite shells.
Replacement: Pyritized brachiopods.
Molds/Casts: Pentamerid brachiopods.
Crystallization: Opal → quartz sponges.
What preserves unaltered soft parts?
Amber (insects), freezing (mammoths).
Name the 7 trace fossil behaviors with examples.
Cubichnia: Resting (Rusophycus).
Domichnia: Dwelling (Ophiomorpha burrows).
Fugichnia: Escape (cnidarian traces).
Repichnia: Crawling (Climactichnites).
Pascichnia: Grazing (Radulichnus).
Agrichnia: Farming (Paleodictyon).
Fodichnia: Deposit feeding (Planolites).
How to remember the geologic time scale?
“Eat Eggs Painted Elegantly” (Eon, Era, Period, Epoch).
