Transcript Chapter 1 Earth Science

Chapter 14
Earth Science
Geologic Time
Words to Know – Section 1
Life and Geologic Time
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Geologic time scale
Eon
Era
Period
Epoch
Organic evolution
Species
Natural selection
Trilobite
Pangea
Division of Earth’s history
into time units based largely
on the types of life-forms that
lived during certain periods.
Geologic
time scale
Longest subdivision in the
geologic time scale that is
based on the abundance of
certain types of fossils and is
subdivided into eras, periods,
and epochs.
eon
Second-longest division of
geologic time; is subdivided into
periods and is based on major
worldwide changes in types of
fossils
era
Third-longest division of
geologic time; is subdivided
into epochs and is
characterized by the types of
life that existed worldwide.
period
Next-smaller division of
geologic time after the period; is
characterized by differences in
life-forms that may vary
regionally.
epoch
Change of organisms over
geologic time
Organic
evolution
Group of organisms that
reproduces only with other
members of their own group
species
Process by which organisms
that are suited to a particular
environment are better able to
survive and reproduce than
organisms that are not
Natural
selection
Organism with a three-lobed
exoskeleton that was abundant
on Paleozoic oceans and is
considered to be an index fossil
trilobite
Large ancient landmass that
was composed of all the
continents joined together
Pangea
Words to Know – Section 2
Early Earth History
Precambian time
 Cyanobacteria
 Paleozoic Era
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Longest part of Earth’s
history, lasting from 4.0
billion to about 544 million
years ago
Precambrian
time
Chlorophyll-containing,
photosynthetic bateria
thought to be one of Earth’s
earliest life-forms
cyanobacteria
Era of ancient life, which began
about 544 million years ago,
when organisms developed
hard parts, and ended with
mass extinctions about 245
million years ago
Paleozoic
Era
Words to Know – Section 3
Middle and Recent Earth History
Mesozoic Era
 Cenozoic Era
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Middle era of Earth’s history,
during which Pangea broke
apart, dinosaurs appeared, and
reptiles and gymnosperms were
the dominant land life-forms
Mesozoic
Era
Era of recent life that began
about 66 million years ago and
continues today; includes the
first appearance of Homo
sapiens about 400,000 years
ago
Cenozoic
Era