Chapter 8: Fossils and Their Place in Time and Nature Flashcards
Thomas Jefferson’s collection of fossils
Megalonyx Jeffersonii Fossil Claws
Strata
layers of rock, representing various periods of deposition
Principle of Faunal Succession
succession of organisms in strata represent successive geological epochs with their characteristic or index fossil (certain layers distinguish certain kinds of fossils)
Types of micro fossils
microbial, plant and animal eukaryotic bacteria, pollen
Types of macro fossils
ammonite, trilobite, fern, crab, soft shell turtle, fish, T-Rex, Eocene primate
Fossils
remains of organisms turned to stone completely or partially through chemical replacement
Paleontology
study of fossils
taphonomy
study of how fossils are formed; study of deposition of plant/animal remains and environment affecting preservation
Sedimentary Rock
formed by sedimentation of water and wind depositing tiny particles of rock, sand, and soil overtime
Gradual Process
observed by Darwin that evolution is gradual, observed by Bown and Rose by looking at gradual evolution of teeth in Eocene primates
Punctuated Equilibrium
observed by Eldredge and Jay- long periods of stasis in exoskeletons of invertebrates, such as trilobites, and then revolutionary rapid change
Order of time scales
Eons (I), Era (A), Periods (a), Epochs (i)
What time period do we live in?
IV: Phanerozoic Eon
C: Cenozoic Era
b: Quaternary Period
iii: Anthropocene Epoch
Nicolaus Steno
1639-1686: danish scholar who discovered geologic pre-history of Earth and its life
Steno’s Law of Superposition
older strata under, younger above; cross cutting younger still
Relative Dating
relative order of events without assigning calendrical dates
Stratigraphic Correlation
matching strata from different sites using index fossils, chemical compositions, physical features, interposing datable layers, give us geochronology in calendrical tiem
Chemical Dating
relative method based on predictable chemical changes over time
Fluorine (relative) Dating
Bones accumulate fluorine bearing soils at a steady rate
Biostrategic (faunal and floral) Dating
Relative method based on first/lasts appearances and associations
Index fossils
common distinctive associated with relative age of particular strata
Cultural Dating
relative method based on time spans of material culture remains
manuport
object carried around from original context for some reason like the Makapansqat cobble/pebble
Dendrochronology
chronometric dating method using annual tree-ring counts, observed by AE Douglas
Isotopes used in Radiometric Dating
C-N U-Pb K-Ar Ar-Ar U-Pb
Radiocarbon Dating
for much younger ages, organism stop intake of carbon 14 at death, so can date until their death
Paleomagnetic Dating
looking at magnetic poles and polarity reversals which is resemble in polarized orientation in sedimentary rock
Amino Acid Dating
absolute method for organic remains, looking at the L-isomes and the D-isomes, called racemization
Electron Spin Resonance Dating
measures radioisotopic concentrations in fossil bones, teeth compared to burial environments
Thermoluminescence Dating
method based on amount of sun’s energy trapped in sediment, stone, and pottery
Genetic Dating
Looking at evolutionary divergences, where there was a change in genes, allowing you to look back at specific events
Foraminifera
Looking ancient environments with micro fossils
C3 Photosynthesis
wet wooded plants, wheat, sugar beets, peas, hardwood trees
3 Cs avoid Carbon 13 and incorporate Carbon 12
C4 Photosynthesis
grassland plants, corn, sugarcane, succulents
4 Cs high in Carbon 13
Paleosols
old soil
