Post on 02-Jul-2015
description
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 .