Civics 5

Class

Lesson One

Theories on the Origin of the

Philippines

Land Bridges Theory

• The Philippines used to be attached to mainland

Asia by land bridges. About 250, 000 years in the

Ice Age or Pleistocene Period, the water level of

the oceans went down and exposed the land that

were thought of as bridges.

Theory of Volcanic Origin

• The Philippine islands came into being out of

the ashes and volcanic materials spewed out

by the volcanoes on the ocean floor.

• These materials accumulated and

formed the islands after millions of

years of eruption.

Continental

Drift Theory of

Alfred Wegener

• All the continents and islands today were once part of one large, compact land mass called PANGAEA.

• Due to

continuous

land

movements,

the land

masses began

breaking up,

creating

islands.

The Theory of Lemurian

Origin

• The Philippines and

other countries of

Southeast Asia were

once part of a bigger

land mass called

Lemuria or Mu.

• Because of

earthquakes and

geological activities,

most of the land mass

sank and only parts

remained including the

Philippine archipelago.

Plate Tectonics

Theory

• According to this

theory, scientists

believe that the

outer shell of the

earth is made up of

thin, rigid plates

that move relative

to each other.

• These plates ride

atop a part of the

earth’s mantle called

the ASTHENOSPHERE.

It is hot, dense and

partially molten.

Motion beneath the

plates causes them

to move in different

directions.

Sometimes the

plates stick to each

other or slip due to

the movement.

Sunda Shelf Theory

• During the

Pleistocene period,

the Philippines was

part of the Sunda

Shelf which is an

extension of Mainland

Southeast Asia .