The was very during the early paleozoic.
rising seas flooded the continents and formed many shallow seas.
an sea is a body of water formed when ocean water floods continents.
most of north america was covered by an inland sea.
middle paleozoic
the early paleozoic ended with a mass extinction event, but many invertebrates survived.
new forms of life lived in huge along the edges of the continents.
soon, animals with called evolved.
the age of fishes
some of the earliest vertebrates were
so many types of fishes lived during the and periods that the middle paleozoic is often called the age of
some fishes, such as the were heavily armored.
on land, and other insects evolved.
earth’s first plants appeared, however, they were and lived in
geology of the middle paleozoic
middle paleozoic rocks contain evidence of major between moving
these collisions created
when several landmasses collided with the eastern coast of north america, the began to form.
by the end of the paleozoic era, the were probably as high as the are today.
late paleozoic
like the early paleozoic, the middle paleozoic ended with a mass extinction event.
many invertebrates and some land animals disappeared.
this marked the beginning of the paleozoic.
the age of amphibians
in the paleozoic, some fishlike organisms spent part of their lives on
tiktaalik was an organism that had and could breathe
it was one of the earliest
amphibians were so common in the late paleozoic that this time is known as the age of
the age of amphibians (cont.)
ancient amphibian species to land in several ways.
they had and could breathe air.
their skins were which slowed loss.
their strong enabled them to move around on
all amphibians, even those living today, must return to the to mate and lay eggs.
the age of amphibians (cont.)
species evolved toward the end of the era.
reptiles were the first animals that did not require for reproduction.
reptile eggs have shells that protect them from
coal swamps
during the late paleozoic, forests grew in swamps along shallow inland seas.
when trees and other plants died, they sank into theis an oxygen-poor environment where, over time, plant material changes into coal.
the coal swamps of the and periods eventually became major sources of coal that we use today.
formation of pangaea
geologic evidence indicates that many continental occurred during the late paleozoic.
as continents moved closer together, new formed.
by the end of the paleozoic era, earth’s continents had formed a giant supercontinent–
a is an ancient landmass which separated into present day continents.
pangaea formed close to earth’s
as pangaea formed, coal swamps dried up and earth’s climate became and
the permian mass extinction
the largest mass extinction in earth’s history occurred at the end of the era.
fossil evidence indicates that percent of marine life-forms, and percent of all life on land became extinct.
this extinction event is called the mass extinction.
the permian mass extinction (cont.)
scientists debate what caused this mass extinction.
the formation of likely decreased the amount of space where marine organisms could live.
it would have contributed to changes in ocean making the center of pangaea
but pangaea formed over many of years.
the extinction event occurred more
the permian mass extinction (cont.)
some scientists hypothesize that a large meteorite impact caused drastic
others propose that massive volcanic eruptions would have ejected and into the atmosphere, blocking out reducing and causing a collapse of
whatever caused it, earth had species after the permian mass extinction.
only the species that could to the changes survived.