The document summarizes the history of Earth and life through geologic time. It describes the four major eons - Hadean, Archean, Proterozoic, and Phanerozoic. Within the Phanerozoic eon, it outlines the three eras - Paleozoic, Mesozoic, and Cenozoic. The Paleozoic saw the rise of early life like plants and amphibians. Reptiles dominated the Mesozoic. Mammals and eventually humans arose in the Cenozoic era from 65 million years ago to present day.

1. The History of the Earth and Its
Life Forms

2. OBJECTIVE
• After going through the discussion, you are
expected to describe the history of the Earth
through geologic time

3. Geologic
Time
Scale

4. GEOLOGIC TIME
• Geologic time, the extensive interval of
time occupied by the geologic history of
Earth.
• The geologic time scale is the “calendar”
for events in Earth history. It subdivides
all time into named units of abstract time
called—in descending order of
duration—eons, eras, periods, epochs,
and ages.

5. A. PRECAMBRIAN
Is the earliest part of Earth's
history.
Approximately 4.1 billion
years ago.

6. 1. Hadean
Eon
The most chaotic eon
because there are severe
volcanic activities and
meteorites constantly
bombarding the Earth.

7. 2. Archean
Eon
Lasted over 1.3 billion years.
The Earth became warm
however its atmosphere
contained only methane
with little to no oxygen.
Orange due to the
abundance of methane
The oceans were green
because of iron and
stromalite field shorelines.

8. 2. Archean
Eon
Most part of Earth is
covered with water.
Apparently, during this
time the continent was
formed.

9. 3.
Proterozoic
Eon
Took almost half of the age
of Earth.
The Proterozoic is a
geological eon spanning the
time interval from 2500 to
538.8 million years ago.
Oxygen level of Earth
reaches to 3% which cause
to rise of multicellular
organism.

10. B. PHANEROZOIC EON
Lasted for 540 million years wherein during
this period many life forms became evident.
This period is known to be the Eon of
“visible life”. It is broken into 3 parts.

11. 1. Paleozoic Era (Early Life)

12. 1. Paleozoic Era (Early Life)
Lasted for 540–245 million years
Marine life forms had developed shells
Plants, giant ferns and marsh plants.
Reptiles began to appear during the late
Paleozoic Era. They seemed like their
Amphibian ancestors but were unlike in that
they could lay their eggs.
.

13. 1. Paleozoic Era (Early Life)
Scientist considers that the remains of these
plants formed the huge coal deposits in many
part of the world. It is also believed that the
oxygen level in the atmosphere approaches
present day concentration..

14. II. Mesozoic Era (Middle Life)
took place at about 246-65 million years,
Age of the reptiles
220 mya- early Mammals
150 mya-first bird
130 mya- first flowering plant
.

17. II. Mesozoic Era (Middle Life)
Pangaea starts to break
apart at about 200 million
years. North America
began to part from Europe
and South America, and
Australia, New Zealand
and India began to
separate from Africa..

18. III. Cenozoic Era (65 million
years ago - present/Late Life)
“Age of Mammals”
Warm-blooded
Animals such as marsupials like
kangaroo, and primitive
mammals roamed the land.

19. III. Cenozoic Era (65 million
years ago - present/Late Life)
During this period, mountains
were uplifted and volcanic
activities became extensive
Human beings appeared and
left their marks on the land, as
observed and seen in the stone
tools that were used...