Fossil Record Flashcards
uniformitarianism
the theory that changes in the earth’s crust during geological history have resulted from the action of continuous and uniform processes.
catastrophism
the theory that changes in the earth’s crust during geological history have resulted chiefly from sudden violent and unusual events.
paleontology
the branch of science concerned with fossil animals and plants.
relative dating
Relative dating is the science of determining the relative order of past events, without necessarily determining their absolute age. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another.
absolute dating
Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word “absolute” implies an unwarranted certainty of accuracy.
superposition
the action of placing one thing on or above another, especially so that they coincide
isotope
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
radioactive decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation.
half-life
An interesting and useful aspect of radioactive decay is half-life, which is the amount of time it takes for one-half of a radioactive isotope to decay.
fossil
Fossils are the preserved remains, or traces of remains, of ancient animals and plants.
trace fossil
a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
mold
Molds. A mold fossil is a fossilized imprint made in the substrate. The substrate is the rock or sediment on which a fossil makes its mark. Unlike cast fossils, mold fossils are hollow.
cast
A fossil formed when an animal, plant, or other organism dies, its flesh decays and bones deteriorate due to chemical reactions; minerals gradually enter into the cavity, resulting in a cast, which is in the general form of the original organism.
unconformity
a surface of contact between two groups of unconformable strata.
mass extinction
A mass extinction is usually defined as a loss of about three quarters of all species in existence across the entire Earth over a “short” geological period of time.
Jurassic period
The Jurassic is a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era.
Cretaceous period
The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At nearly 80 million years, it is the longest geological period of the entire Phanerozoic.
Devonian period
The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago, to the beginning of the Carboniferous, 358.9 Mya. It is named after Devon, England, where rocks from this period were first studied.
Quaternary period
Quaternary is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy. It follows the Neogene Period and spans from 2.588 ± 0.005 million years ago to the present.
Permian period
The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous period 298.9 million years ago, to the beginning of the Triassic period 251.902 Mya. It is the last period of the Paleozoic era; the following Triassic period belongs to the Mesozoic era.
