THE HISTORY OF THE EARTH

Millions of years ago, giant reptiles called dinosaurs roamed the

earth. They reigned over the earth for more than

100 million years. THEN THEY DISAPPEARED……

What could have caused

their disappearance?.

..

Scientists believe that changes

occurred on the earth throughout history that

affected living things.

A cooling of the climate may have

caused the dinosaurs to

die out…

When the sea level rises, areas of low-

land become covered with water.

This causes life forms on the land to

be replaced with sea life..

GEOLOGIC TIME

SCALE

ERA-is a time based on the changes in the earth’s crust and on stages of development of certain life forms.

PERIOD

- is a time interval into which eras are divided.

The Carboniferous period was the period of time when coal, or rocks made of

carbon, formed.

PRECAMBRIAN ERA

IT BEGAN WHEN THE EARTH CAME INTO

EXISTENCE ABOUT 4.6 BILLION YEARS AGO.

FEW FOSSILS ARE FOUND IN

PRECAMBRIAN ROCKS.IT SHOWS SOME

EVIDENCE OF SIMPLE FORMS OF LIFE, SUCH

AS BACTERIA AND ALGAE.

Impressions of soft-bodied animals, such

as jelly-fish, corals, and

starfish, have been found in late

Precambrian rocks.

PALEOZOIC ERA

“The Era of Invertebrates”

This era is dominated by animals called invertebrates.

INVERTEBRATE- is an animal that does not have a bony skeleton. However, it can contain hard parts, such as a shell.

JELLYFISH

Click icon to add picture

CAMBRIAN PERIOD

During the Cambrian Period,

much of the continental areas were covered by shallow seas.

TRILOBITE

BRACHIOPOD

ORDOVICIAN

PERIOD

During this period, life

forms similar to clams,

squid, and octopuses

began to take over as the major life

forms.

The first vertebrates

were fish covered with bony plates. The bony fins

may have eventually become the limbs of the

first land animals

PICTURE NG NAUTILOD, EURYPTERID

SILURIAN PERIOD

DURING THIS PERIOD, THE

EASTERN COAST OF NORTH AMERICA WAS UPLIFTED. A LARGE

INLAND SEA FORMED IN THE EASTERN PART OF THE US.

Picture silurian

Lichens,mosses, scorpions

Devonian Period

IN THIS PERIOD, FISH HAD BECOME

ABUNDANT. SCIENTISTS BELIEVE THAT SOME OF THIS

FISH DEVELOPED LUNGS THAT COULD BE USED TO BREATH

AIR.

LUNGFISH

frog

Amphibians- are animals that live in water when they are young but live on land when they are adults.

Giant tree ferns evergreens

Carboniferous period

It was the period of time when coal, or rocks

made of carbon, formed.

Permian period

The climate became much colder, causing

ice ages.

Ice ages, glaciers

Conifer trees

Mesozoic Era

“THE AGE OF REPTILES”

DURING THIS TIME, PANGAEA BROKE INTO PIECES AND FORMED CONTINENTS AS WE KNOW THEM TODAY.

Among the animals, reptiles were best

able to adapt to this environment.

Sierra nevada mountains rocky mountains

Triassic period

Oysters, lobsters, clams, grasshoppers, termites, flies

-was a marine reptile that lived during the Triassic Period- was about 3 m (10 ft) in length. -Its long, angular jaws and sharp teeth provided it with a powerful trap for catching fish and other small marine animals.

Nothosaurus

Coelophysis

-was one of the earliest dinosaurs-these slender, lightweight carnivores grew to 3 m (10 ft) long-they lived about 220 million years ago during the late Triassic Period.

JURASSIC PERIOD

THE WORD DINOSAUR COMES FROM THE GREEK AND MEANS “TERRIBLE

LIZARD”.

BRONTOSAURUS

-plant eating

dinosaur

-largest that

ever lived on

land

-21 meters

long and

weighed

about 70 t.

diplodocus

Mamenchisaurus

-was a large plant-

eating dinosaur that

lived during the late

Jurassic Period,

about 150 million

years ago.

-was closely related

to Diplodocus, but

its neck, which

consisted of 19

vertebrae, was

longer than that of

any other dinosaur.

-was about 25 m (82

ft) long and

weighed about 10

metric tons.

stegosaurus

-was a

dinosau

r with

plates

on the

back.

allosaurus-a

dinosa

ur

that

ran on

its

hind

legs

and

ate

meat

CRETACEOUS PERIOD

tyrannosaurus

-was over 13 meters long and weighed about 8 t.-it was a large , two legged meat-eater

It could stand on its hind legs, which

were fit for running. Although

Leptoceratops had no horns on its

head, the angular peaks on its skull

were the beginnings of the neck armor that characterized

later horned dinosaurs such as

Triceratops.

Leptoceratops

Pteranodon

triceratops

By the end of the Cretaceous Period, the

dinosaurs and about half of all other life forms had

disappeared.When many forms of life die in a short period of time, it is called a mass

extinction.

THE DUST AND SMOKE FROM WORLDWIDE VOLCANIC ACTIVITY

COULD HAVE BLOCKED OUT SUNLIGHT.

-proposes that the dust in the atmosphere came from a meteorite that hit the earth.

Meteorite Impact Hypothesis

CENOZOIC ERA

It is the era in which we live and in which

mammals became dominant.

TERTIARY PERIOD

During this period, some of the great mountain

ranges formed, including the Alps, Himalayas, and

Andes.

Alps, himalayas, andes

PALEOCENE EPOCH

DURING THIS EPOCH, MAMMALS WERE SMALL. PLANTS

RESEMBLED TROPICAL PLANTS OF

TODAY.

EXAMPLE ORG PALEOCENE

Eocene epoch

Ancestors of modern mammals

WHALE HORSE

Oligocene

Epoch

Tropical plants were replaced by grasses and pine trees. Apes, elephants, and members of the cat and dog families existed.

Miocene Epoch

Pliocene

Epoch

Glaciers began to form in the Northern Hemisphere. The sea level fell. Animals crossed land that was no longer covered by water.

QUATERNARY PERIOD

During this period, the climate became colder

and ice sheets advanced.

Pleistocene Epoch

“The Ice Age”Because of the cold climate, animals had

to either develop protective coverings

or move to other regions.

Holocene Epoch

During this epoch, the earth's climate became

warmer……

It is in the Holocene Epoch that human civilization

arose...