Fossil Record

Question 1

uniformitarianism

Answer 1

principle or assumption that the same natural laws and processes that operate in the universe now have always operated in the universe in the past and apply everywhere in the universe.

Question 2

catastrophism

Answer 2

theory that the Earth has been affected in the past by sudden, short-lived, violent events, possibly worldwide in scope. This was in contrast to uniformitarianism

Question 3

paleontology

Answer 3

study of fossils.

Question 4

relative dating

Answer 4

science of determining the relative order of past events

Question 5

absolute dating

Answer 5

process of determining an age on a specified time scale in archaeology and geology

Question 6

superposition

Answer 6

principle of quantum theory that describes a challenging concept about the nature and behavior of matter and forces at the sub-atomic level.

Question 7

isotope

Answer 7

Each atomic number identifies a specific element, but not the isotope; an atom of a given element may have a wide range in its number of neutrons. The number of nucleons (both protons and neutrons) in the nucleus is the atom’s mass number, and each isotope of a given element has a different mass number.

Question 8

radioactive decay

Answer 8

is the process by which a nucleus of an unstable atom loses energy by emitting radiation.

Question 9

half-life

Answer 9

the time taken for the radioactivity of a specified isotope to fall to half its original value.

Question 10

fossil

Answer 10

the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.

Question 11

trace fossil

Answer 11

a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.

Question 12

mold

Answer 12

form (an object with a particular shape) out of easily manipulated material.

Question 13

cast

Answer 13

an object made by shaping molten metal or similar material in a mold.

Question 14

uncomformity

Answer 14

contact between sedimentary rocks that are significantly different in age, or between sedimentary rocks and older, eroded igneous or metamorphic rocks.

Question 15

mass extinction

Answer 15

widespread and rapid decrease in the amount of life on Earth.

Question 16

Jurassic period

Answer 16

system that extends from 201.3± 0.6 Ma (million years ago) to 145± 4 Ma; from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles.

Question 17

Cretaceous period

Answer 17

Cretaceous Period, about 65 million years ago. As everyone knows, this was the great extinction in which the dinosaurs died out, except for the birds, of course.

Question 18

Devonian period

Answer 18

geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 419.2 ± 3.2 (million years ago), to the beginning of the Carboniferous Period, about 358.9 ± 0.4.

Question 19

Quaternary period

Answer 19

geologic time period that encompasses the most recent 2.6 million years — including the present day.