Cards (15)
era that began about 66 million years ago, known as the "Age of Mammals"
Began 4.6 billion years ago, when life first appeared: cyanobacteria, invertebrates/atmosphere began to form
Earth's
amount of time for half a radioactive substance to decay
middle life (245-144 million years ago); rise of mammals and dinosaurs; the rise of birds; extinction of dinosaurs, rise of flowering plants
A huge period of time in the earths history.
a place where an old, eroded rock surface is in contact with a newer rock layer
a scientific method used to determine the age of an artifact
a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
scale used by paleontologists to represent evolutionary time
element used to determine the age of an artifact
extinct marine arthropods
The death of every member of a species
the part of geologic time 570-245 million years ago ; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant
the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element
any method of determining whether an event or object is older or younger than other events or objects
