Geological time scale ppt

1. GEOLOGIC
TIME SCALE

2. GEOLOGIC TIME SCALE
A record of the life forms and Geological
events in Earth’s history.
 Scientists developed the time scale by
studying rock fossils world wide.

4. HADEAN EON
Occured 4.6 billion years ago. During this time, the solar system
was forming within a cloud of dust and gas known as the solar
nebula, which eventually spawned planets and etc.
PRECAMBRIA
N
EON

5. HADEAN EON
the earth started cooling and the outer edge of the
planet solidified from molten lava to a solid crust.
Water rained from the atmosphere and created oceans.

6. ARCHEAN EON
Between 4 billion and 2.5 billion years ago, the fist
form of life on our planet was created in the oceans.
PRECAMBRIAN
EON

7. Exactly when or how it happened is unknown, but microfossils of this
time indicate that life began in the oceans about 3.5 billion years ago.
By the end of the Archean, the ocean floor was covered
in a living mat of bacterial life.

8. Also called the “age of hidden life”, started 2.5 billion years ago. In
this time, enough shield rock had formed to start recognizable
geologic processes such as plate tectonics.
PRECAMBRIAN
EON

9. Contains many definite traces of primative life-forms
the fossils remains bacteria and blue-green algae, as well as
of the first oxygen-dependent animals.

10. The time which abundant animal and plant life has
existed. It covers 541 million years to the present.

11. The Phanerozoic Eon is subdivided into three ERA
Paleozoic Era Mesozoic Era Cenozoic Era

12. The era ran from about
542 million years ago to
25 million years ago.
• The era began with the breakup of one
supercontinent and the formation of
another. Plants became widespead.
• divided into the CAMBRIAN, ORDOVICIAN,
SILURIAN, DEVONIAN, CARBONIFEROUS,
and PERMIAN PERIODS.

13. CAMBRIAN PRERIOD
known for ushering in an explosion of life on Earth. This “Cambrian explosion” included
the evolution of Anthropods (ancestors of today’s inects and crustaceans)
and Chordates (animals with rudimentary spinal chords).
New organisms, invertibrates, first fishes, ALL LIFE is under the sea

15. ORDOVICIAN PERIOD
Marked in the fossil record by an abundance of marine invertebrates.
Perhaps the most famous of these invertibrates was the trilobite, an
armored anthropod that scuttled around the seafloor for about 270
million years before going extinct.
The new organisms take on different forms (diversification)

17. SILURIAN PERIOD
was the evolution and diversification of fish. Not only does this time period mark the wide and
rapid spread of jawless fish, but also the appearances of both the first known freshwater fish and
the first fish with jaws.
Insects, Vascular plants, jawed fishes, Large reefs

18. DEVONIAN PERIOD
is otherwise known as the Age of Fishes, as it spawned a remarkable variety of fish. The
most formidable of them were the armored placoderms, a group that first appeared
during the Silurian with powerful jaws lined with bladelike plates that acted as teeth.
Age of fishes, first amphibians, first land plants, and ammonites

19. CARBONIFEROUS PERIOD
Long before birds evolved, tetrapods began laying eggs on land for the first time
during this period, allowing them to break away from an amphibious lifestyle.
Highest oxygen content, ABUNDANTFORESTS,, First reptiles evolved from amphibians

21. PERMIAN PERIOD
This period would end with the largest mass extinction ever: the permian extinction. Before the
the permian mass extinction, through the warm seas teemed with life. Coral reefs flourished providing
shelter for fish and shelled creatures, such as nautiloids and ammonoids. Northern conifers and ginkgo
trees evolved on land. Terrestrial vertebrates evolved to become herbivores, taking advantage of the new plant life
that had colonized the land.
Formation of Pangea, dry climate favored reptiles, first gymnosperms (cone plants)

22. Contains the Triassic, Jurassic, and Cretaceous Periods.
This peroid, which spans from about 252 million years ago, was also known as the age of
reptiles or the age of Dinosaurs bacause of its famous inhabitants.
The “Middle Life” era, life diversified
rapidly and giant reptiles, dinosaurs, and
other monstrous beasts roamed the Earth.
a shift to land life from sea life, age of reptiles, hot and
humid climate.

23. saw the rise of repitiles and the first dinosaurs.
Rise of diapsid reptiles who survived the Permian extinction, mammals, and flies.

24. Marked by the presence of dinosaurs and the first appearance of birds.
Dinosaurs, angiosperms (cycads), feathered reptiles, marine reptiles, and birds.

25. Plesiosaur
Hadrosaurs
Giganotosaurus
Deinonychus

26. known for its iconic dinosaurs, such as Triceratops, and pterosaurs such as Pteranodon.
Separation of Gondwana and Laurasia, Flowering plant + pollinators, Placenta mammals

27. Divided into Paleogene, Neogene, and Quaternary Periods.
Began about 65 million years ago and continues into present, is the third documented era
in the history of Earth. The current locations of the continents, nd their modern-day
inhabitants, including humans, can be traced to this period. The Cenozoic era is also known
as the age of many groups of giant mammals and allowing smaller species to thrive and
diversify because their predators no longer existed.

28. Consist of the Paleocene, Eocene and Oligocene Epochs.
The beginning of the Paleogene period was time for the mammals that survived from
the cretaceous period. Later in this period, rodents and small horses, such as Hyracotherium,
are common and Rhinicerouses and Elephants appear. As the period ends, dogs, cats and pigs
become commonplace.

29. Includes the miocene and pliocene epochs. The Neogene period gives rise to early primates,
including early humans. Bovids, including cattle, sheep, goats, antelope and gazelle, flourish
during this period.

30. (2.6 million to the present year) consisting of the pleistocene and holocene epochs. Cave Lions,
Sabre-toothed cats, cave bears, giant deer, woolly rhinoceroses, and woolly mammoths were
prevailing species of the Quaternary period