Vocabulary
The number of people born per 1,000 individuals for a certain period of time
Birth Rate
The preserved remains or traces of an organism that lived in the past
Fossil
A record of the geologic events and life forms in Earth's history
Geologic Time Scale
A vertebrate that controls its own body temperature
Mammal
The first birds evolved during the ____________ era
Mesozoic
The practice of using less of a resource so that it can last longer
Conservation
The age of a rock given as the number of years since the rock formed
Absolute Age
One of the three long units of geologic time between Precambrian and the present
Era
Animals that have scaly skin
Reptile
Into which units is the geologic time scale subdivided?
Eras and Periods
Contamination of Earth's land, water, or air through the release of harmful substances into the environment
Pollution
The geologic principle that states that in horizontal layers of sedimentary rock
Law of Superposition
One of the units geologic time into which geologists divide eras
Period
Amphibian
Which event occurred during the Cenozoic era?
Spread of Mammals
A condition in which the number of humans grows beyond what the available resources can support
Overpopulation
The process in which the nuclei of radioactive elements break down
Radioactive Decay
What is the geologic time scale?
A chronological calendar of Earth's history
An event during which many types of living things become extinct
Mass Extinction
What were Earth's earliest multicellular organisms?
First single-celled and multi-celled organisms evolved
A rate of change that increases more and more rapidly over time
Exponential growth
A gap in the geologic record that shows where rock layers have been lost due to erosion
Uncomformity
How is Precambrian Time different from the other divisions of the geologic time scale?
It covers roughly 88% of Earth's history
An animal with a backbone
Vertebrae
The geologic time scale is a record of _____________ and _____________.
Geologic events, Evolution of life forms