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| HISTORY
AND GEOGRAPHY |
| Which animal group do humans belong to ?
Who are humans closest relatives ?
Who were the first human beings ?
How the man's ancestors evolved ?
What are oceans and seas ?
What are Tides ?
What is Weather ?
What is Climate ?
Which animal group do humans belong to ? |
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Humans belong to the group of mammals called primates, which means
first. Humans are considered to be the most evolved creatures on the earth, although there
is no top place for any living group in the evolution. The primates are generally divided
into two groups, prosimians and anthropoids.
While Prosimians generally include bush babies, lemurs and aye- ayes, Anthropoids are
highly intelligent and have large brains that include apes, monkeys and humans. Humans are
members of one species Homosapiens. While humans live on ground and walk on two legs, most
primates walk on four legs and live on trees. |
Who are humans closest relatives ? |
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The closest relatives of human beings are the Chimpanzees and are
generally found in Africa on grasslands and in the woods. Like the humans even Chimpanzees
are observed using tools and so are believed to be the most intelligent of the primates.
To help them get food they use rocks and stones. They also use grass blades and sharp
sticks to help them poke out termites to eat. Watching each other at work they learn to
make tools. They attack strangers by throwing rocks on them and guard their territory.
Another large primate group close to human beings are the Gorillas, who are found in
Central and East Africa. Several females and their young ones live in family groups led by
a large adult male called Silver Back. They sleep in nests made of leaves and dry broken
branches and mainly stay on the ground. |
Who were the first human beings ? |
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The most important living beings on Earth are Humans. About 50,000
years ago the first human beings like us are said to have lived on earth. Human beings
developed over million of years and were related to apes and monkeys, in 1859 an English
Scientist Charles Darwin suggested. A number of fossil skulls, fossil bones and the other
remains of human-like creatures have been found and with these fossils, Darwin was proved
right. Scientists believed, our ancestors were small and funny animals about 70 million
years ago.
These human like creatures turned into monkeys, chimpanzees and apes very slowly. The
Earth began to change and forests disappeared after about 25 million years. As most trees
had disappeared these ancestors of man learned to live on the ground. Some of their
descendants stayed on the trees and those who adjusted to living on land began walking
upright. For carrying things they started using their hands. They became cleverer than
other animals as their brain became larger. |
How the man's ancestors evolved ? |
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Man's ancestors lived on trees who are called as apes. Apes are
tailless monkeys who left trees and started living on open grounds. They started walking
on two legs, which left their hands to do and carry other things. The ape's hands were
specially developed for swinging on trees but now the hands could be used for many things.
The long fingers and thumbs, which are so different from the animal paw, could hold tools
and weapons. The most important difference between man and its ancestor apes is
intelligence. This intelligence to make fire or to defend itself could be used by no other
animal. |
What are oceans and seas ? |
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Large bodies of water are called oceans. On the earth there are four
oceans which are not separate from each other. Arctic is the smallest, whereas Pacific is
the largest ocean. Through water currents, water from one-ocean flows into another.
Smaller water bodies identified in the oceans are seas. Seas and oceans have other water
bodies like bays, straits, gulfs, etc. |
What are Tides ? |
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Tide is the rise and fall in sea level. Tides are caused by the
gravitational pull of the moon and to a lesser extent of the sun. Every 24 hours and 50
minutes the moon rotates around the earth and thus there are two high and two low tides.
When the moon is over head at any place, it exerts a gravitational pull on the water
beneath it causing a high tide and because of this tides occur.
The highest spring tides occur when the sun, moon and earth are in a straight line. This
is precisely, because the gravitational pull of the sun and moon is combined. When the
moon, earth and sun form a right angle to each other, the lowest neap tides occur. And
thus, the gravitational pull of the sun and moon are opposed. |
What is Weather ? |
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Weather refers to the amount of water vapour in the air. It is
changeable and varies from place to place. At any particular place and time it is the
state of air. Over a short period of time weather of a place are the conditions of the
atmosphere. The condition of a particular area is indicated as hot or cold, wet or dry,
windy or calm day. But in some places weather remains the same through out the year, in
others it changes every day.
Weather normally depends on the moving air, the heat of the sun and on winds. Because the
earth is curved, the sun heats the earth at equator. And so the air around the equator is
warmer, than the air around poles. Warm air moves towards north and south poles and gets
cooler on its way. It forms a circular movement and returns towards the equator. The other
air movements between the equator and the poles are due to the rotation of the earth that
pushes the winds to the west, over various parts of the world, the heating and cooling of
the land causes differences in the air temperature. |
What is Climate ? |
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The average or typical weather condition of a place over a long
period of time is called climate. Since the sun shines almost overhead, the area near the
equator has a hot climate. It gets cooler and cooler as we move away from the equator. It
is always too cool at poles. Climate is also affected by the ocean currents that carry
warmth around the world. |
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