1. Time scale
History of earth

3. Time scale divided into 4 eras
Precambrian era
Paleozoic era
Mesozoic era
Cenozoic era

4. PRECAMBRIAN ERA First rocks are formed
it covers large period of time up to 600 million years past
First rocks are formed
first stromatolites and protozoa's
First earth warms and jelly fishes.
Soft bodies organisms started in marine conditions.

5. Paleozoic era This era is from 600-225 million years
This era is divided into 6 period
Cambrian period
Ordovician period
Silurian period
Devonian period
Carboniferous period
Permian period

6. Cambrian period Earth covered by seas and volcanic activities
Invertebrates lived in the seas and trilobites were more number.

7. Ordovician period Mountain building started in this period.
Silt deposits are common.
Sudden diversification of metazoan family.

8. Silurian period 443-417 million years during.
First land animals formed.
Breathing animals formed in the seas.
Coral reefs made their first appearance during this period.

9. Devonian period First dry lands are formed.
Shales and slates are formed.
Forests developed on land
Snakes, insects and amphiboles have formed.

10. Cambrian period coal and other minerals have formed.
Huge trees and reptiles are appeared.

11. Permian period
Lot of earth moments and mountain building started in place.
Melting Glaciers formed.
Sedimentary deposits developed.
Trilobites become extant

12. Mesozoic era this era is from 225-265 million years
it divided into 3 periods
Triassic period
Jurassic period
Cretaceous period

13. Triassic period Sand stone , copper and uranium deposits have formed.
Tortoise have appeared.
First dinosaurs appear.
Pangaea holds together. Hot ,dry conditions dominate center of pangea.

14. Jurassic period Dinosaurs and other large animals increased on earth.
Bird like archaeopteryx and reptiles were common.
First birds have apeared.

15. Cretaceous period Chalk deposits formed. Flowering plants developed.
Reptiles and mammals increased.
Dinosaurs has extant.

16. Cenozoic era It is from 65 million years in the past to recent times.
This era has two periods.
Tertiary period
Quaternary period

17. Tertiary period
Tertiary period has 5 epoch. Paleocene epoch Eocene epoch Oligocene epoch Miocene epoch Pliocene epoch

18. Tertiary period
In Paleocene epoch flowering plants increase and large animals totally disappear.
In Eocene epoch mammals increased , rocky mountains developed.
In Oligocene epoch cats , dogs , rats, bears have appear.
in Miocene epoch flowering plants, grazing mammals appeared.
Pliocene epoch present features developed on earth.

19. Quaternary period it has two epoch
In Pleistocene epoch, big animals like wooly
Lion . man also developed in this epoch.
2.In Holocene Ice sheets have decrease , coast-lines and land shapes have formed
man started cultivation in this epoch.

20. Presented by jayanth sai kishore. P (pj) roll no:- 5107
The end