Chapter 9 Flashcards
paleontology
The study of extinct organisms, based on their fossilized remains.
fossils
The preserved remnants of once-living things, often buried in the ground.
geology
The study of the earth.
taphonomy
The study of what happens to the remains of an animal from the time of death to the time of discovery.
strata
Layers of rock.
stratigraphy
the study of the order of rock layers and the sequence of events they reflect.
geologic time scale (GTS)
The categories of time into which Earth’s history is usually divided by geologists and paleontologists: eons, eras, periods, epochs
provenience
The origin or original source (as of a fossil).
relative dating techniques
Dating techniques that establish the age of a fossil only in compari-son to other materials found above and below it.
lithostratigraphy
The study of geologic deposits and their formation, stratigraphic rela-tionships, and relative time rela-tionships based on their lithologic (rock) properties.
tephrostratigraphy
A form of lithostratigraphy in which the chemical fingerprint of a volcanic ash is used to correlate across regions
biostratigraphy
Relative dating technique using comparison of fossils from dif-ferent stratigraphic sequences to estimate which layers are older and which are younger.
calibrated relative dating techniques
Techniques that can be correlated to an absolute chronology.
chronometric dating techniques
Techniques that estimate the age of an object in absolute terms through the use of a natural clock, such as radioactive decay or tree ring growth.
radiometric dating
Chronometric techniques that use radioactive decay of isotopes to estimate age.
isotopes
Variant forms of an element that differ based on their atomic weights and numbers of neutrons in the nucleus. Both stable and un-stable (radioactive) isotopes exist in nature.
half-life
The time it takes for half of the original amount of an unstable isotope of an element to decay into more stable forms.
parent isotope
The original radioactive isotope in a sample.
daughter isotope (product)
The isotope that is produced as the result of radioactive decay of the parent isotope.
potassium–argon (K–Ar)
dating Radiometric technique using the decay of 40K to 40Ar in potassi-um-bearing rocks; estimates the age of sediments in which fossils are found.
argon–argon (40Ar/39Ar)
dating Radiometric technique modified
from K–Ar dating that measures 40K by proxy using 39Ar. Allows measurement of smaller samples with less error.
fission track dating
Radiometric technique for dating noncrystalline materials using the decay of 238Ur and counting the tracks that are produced by this fission. Estimates the age of sedi-ments in which fossils are found.
cosmogenic radionuclide dating
Radiometric dating technique that uses ratios of rare isotopes such as 26Al, 10Be, and 3He to estimate the time that sediments and the fos-sils in them have been buried.
paleosol
Ancient soil.
plesiadapiform
Mammalian order or suborder of mammals that may be ancestral to later Primates, characterized by some but not all of the primate trends.
prognathic face
Projection of the face well in front of the braincase.
postorbital bar
A bony ring encircling the lateral side of the eye but not forming a complete cup around the eye globe.
diastema
Gap between anterior teeth.
adapoids
Superfamily of mostly Eocene primates, probably ancestral to all strepsirhines.
omomyoids
Superfamily of mostly Eocene primates, probably ancestral to all haplorhines
dental apes
Early apes exhibiting Y-5 molar patterns but monkey-like postcra-nial skeletons.
r-selected
Reproductive strategy in which females have many offspring, interbirth intervals are short, and maternal investment per offspring is low.
k-selected
Reproductive strategy in which fewer offspring are produced per female, interbirth intervals are long, and maternal investment is high.
molecular clock
A systematic accumulation of
genetic change that can be used to estimate the time of divergence between two groups if relative rates are constant and a calibra-tion point from the fossil record is available
relative rate test
A means of determining whether molecular evolution has been occurring at a constant rate in two lineages by comparing whether these lineages are equidistant from an outgroup.
