Continental
drift is the slow movement of continents over the surface of Earth. The
geological theory explaining continental drift is plate tectonics. The large,
more or less rigid rafts of rock on which the continents float are called
plates. Tectonics are any large-scale processes that shape Earth's crust, from
the Greek tekton for “builder.” Earth-shaping processes that involve plates are
therefore termed “plate tectonics.”
Over
geological time—millions or billions of years— continental drift has a strong
effect on climate, both local and global. Rearrangement of the layout of oceans
and continents changes the ocean circulation pattern, leading to warming or
cooling. In addition, the regional climate of land mass changes gradually as
the land moves toward or away from the equator. When continents temporarily
stick together in larger masses, climate is changed over large areas by shifted
rainfall patterns (the interiors of large continents tend to be dry).
Volcanoes, earthquakes, and the creation of mountain ranges are all caused by
plate tectonics, and these can also affect regional or global climate.
Volcanoes, for example, can affect climate by adding greenhouse gases to the
atmosphere. Continental Drift has affected the evolution of animals and distribution,
the world’s geographical positions and the world's climates. Originally all of the world's surface land
was located in one region on the globe, Pangea. Then Pangaea split apart in the
Triassic Period (245 to 208 million years ago) into a southern landmass,
Gondwanaland, and the northern landmass Laurasia. By the end of the Cretaceous
period, Continents split again into land masses that look like present day
continents.
Effects
The
rearrangement and displacement of huge landmasses has helped create the
diversity which we see present in modern day animals. Without these effects,
the life present on earth today would have been very different. The earth is
filled with so many different types of creatures. We can say that
"Speciation" led to this amazing diversity. Speciation is a
phenomenon that normally takes place when a group of animals of the same
species find themselves isolated from one another. Isolation can occur
geographically by great distances, rising mountains or large bodies of water. They
can also occur from biological or behavioral barriers.
One
species is distinguished from another by their inability to create viable
offspring together, and this is the precise effect that isolation can have on
an animal species. Once a group of animals of the same species becomes split
apart or isolated, they begin to be changed, molded and fashioned by the hand
of natural selection to more properly fit in with their surroundings. After a
period of time these two groups begin to be so different anatomically and
genetically that soon it becomes impossible for them to procreate. This
inability for two animals that were once the same species, to create viable
offspring is called speciation. An example of this is the differences between
Placental and Marsupial mammals. Before 130 million B.C. the land mass of
Gondwanaland was the home to many types of mammals. Thanks to plate tectonics
it was split in two to create modern day South America and Australia. Any
mammals called Gondwanaland their home and after it split, two very different
types of mammals emerged. One kind of mammals were the placental mammals, the
order to which they belong. And the other type is called Marsupial mammals;
these evolved into modern day mammals like kangaroos, koalas, wallabies, wombats
and Tasmanian devils. They have a pouch in which they carry their infant. But
the point here is Marsupial mammals only exist in Australia, except for the
opossum which is found in some parts of South America. The answer to this is
that species were isolated geographically, and they started to evolve over
times but differently because they did not live in the same environments and
that is why you see the variety between placental and marsupial mammals.
The
continental drift also drifted with resources, some minerals and oil are only
found in specific areas. For example Zambia and Congo DR are the only countries
in Africa with a lot of copper and Chile in Europe. Oil is mainly found in the
Middle East.
Earthquakes
and Tsunamis are caused by the movements of the plates. When a lateral slipping
plate movement occurs, the pressure and the force from the collisions of this
type of movement cause earthquakes to occur. This is more explained in my Types
of Plate Movement section. This is very important because of the recent Tsunami
devastations in south Asia. No one expected those Tsunamis to ever come. That
is why it is crucial for scientists to study the effects of continental drifts
to figure out ways to discover dangers of locations where these devastations
could possibly occur. Hundreds of thousands of lives were lost during this
epidemic. We have to start figuring out ways to prepare ourselves from these
types of disasters. And science is definitely the key to understanding the
secrets of earthquakes.
It
is believed that up now the earth has not rested; it still moves an inch after
several years. Continental drift is the reason we have a diversity of species
in the world today i.e. diversity of animal species and plant species. A lot of
wildlife species are found in miombo forest and savannah which is in Africa but
there are some wildlife species that are only found in Australia and Europe.
Continental drift affected the climate and some species could not cope with the
change in climate and hence they went into extinction. Some stronger species
evolved and adapted to new environments. The continental drift, drifted with
some species and these species could not return to their fellow families
because of the barrier between them. The continental drift has caused lot
disasters like earth quakes and tsunami.
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