Anthropology 1: Fossils and the Geologic Time Scale

fossil

-preserved remains (or traces) of an organism that existed in the past -bones are mineralized (turn into stone): organic material is replaced by minerals from the soil -paleontology= the study of fossils -paleoanthropology= the study of human fossils

taphonomic factors that affect the preservation of bones and fossils

-trampling - scavenging -weathering (sun, erosion) -water transport - animals chewing on he bones

fossilization process for open-air sites

1) animal dies next to water source 2) soft tissues decompose/are eaten, only bones remain 3) bones are damaged while they are exposed *the more time they lay out outside, the more damaged they become 4) bones are covered by water 5) bones are buried, mineralization occurs 6) erosion exposes fossils

fossilization process for cave sites

1) caves form underground 2) cave continues to expand 3) cave opening reaches surface, causing things to fall in *talus cone forms= pile of things that fall in cave 4) talus cone blocks cave entrance; bones mineralize; talus cone hardens into breccia *breccia= rock made out of different types of matter (dirt, bone, rain water, plant matter, etc.) 5) cave collapses *talus cone disappears due to surface collapsing thus leveling off 6) erosion exposes fossils

two types of fossils

Physical remains -bones, teeth Ichnofossils or trace fossils -footprints, coprolites -species was present in the past even if no physical of them coprolites= fossilized poop

taphonomy

factors that affect remains from the time of death to discovery

Principles of Original Horizontality

rock layers are deposited parallel to the earth's surface

Principles of Superposiiton

sediments on top younger than sediments further down superposition: older layers are covered by more recent layers

stratigraphy

sequence of rock or soil layers