1
As soon as spring brings a new growth of
bushes and berries, bears start feeding. They eat and eat. All through the
spring and summer their feeding goes on. The bears build themselves up. They
store food and fats that they will need in the fall when they start their long
sleep.
As days grow shorter, and the temperature
begins to fall, bears hunt for a sleeping place. It may be a shallow cave, or a
deep crack between rocks. Some bears end up sleeping in hollow logs. Logs seem
to be bears’ favourite places. Bears seem to choose small spaces. They can keep
warmer in a cave that’s just large enough to hold them than in a larger cave.
They often line their sleeping place with leaves and dried grass.
All through their winter naps, bears will
not eat. Often they will sleep for 7 months, moving only now and then.
2
Many lands that had once been swamps were drained or filled
in. There are different reasons why people drained swamplands. Some were
drained to fight diseases caused by insects that lived in them. Because swamps
were considered unpleasant places in which to live and harmful to health, many
people thought that unless they were drained the land was worthless.
Other swamps were drained to make new land. As the
population grew and more land was needed, people drained swamps or filled them
to make room for more farms and factories, more roads and airports.
Few people thought that it might be harmful to get rid of
swamps. As swamps disappeared, other things happened. There were both more
floods and more droughts than before. There were also more fires, for swamps
had acted as firebreaks. Hunters noticed that there was less wild game. Wild
life that once lived in the swamps was dying out, because it had no place to
live.
3
Until
fairly recently, it was a mystery how certain large bees, bumblebees in
particular, were able to fly. To scientists who study the physical laws of
flight a bee’s body seemed too heavy and its wings too small for it to become
airborne and remain so. Bees “can’t” fly… but do. The mystery became so
intriguing that a few scientists decided to study it.
Most
insects fly by using muscles that flap their wings with great speed. For
example, the locust beats its wings at a rate of about 20 times per second to
fly. Other flying insects have to beat their wings even faster – some as
rapidly as 100 times per second. But bees must work extra hard to become
airborne. Honeybees, for instance, must beat their wings about 200 times a
second to fly. Yet larger bees – like bumblebees – whose bodies are heavier,
wider, and longer – have to do even better.
4
The
mystery of why trees don’t stop growing is still unsolved. Human beings usually
stop growing sometime during their teens. Many animals reach full growth within
a year. Others are fully grown in
just a few years. Birds and insects also
stop growing at a certain age. But trees keep growing as long as they live.
Trees
live, grow, and reproduce themselves by an amazing process. The thousands of
leaves put forth by the tree breathe for it and manufacture its food. Its root
system gathers minerals and vast quantities of water. To carry this water to
the leaves, the tree is equipped with an intricate circulation system that
extends upward from the millions of root hairs through the trunk and branches.
The trunk holds the leaves up to the sunlight, sends them water from the roots,
and gets food back from them. Then seed sare born in flowers or cones.
5
No single person or culture
invented the alphabet – it has evolved over centuries. In order to understand
modern alphabets, we must take a trip back through time. Archeologists have
discovered cave paintings thousands of years old that document the first forms
of alphabets. In fact, some of the oldest alphabetic symbols have been found in
the Middle East more than 5,000 years ago.
One of the earliest forms of
the alphabet was hieroglyphics. Hieroglyphics were single symbols that stood
for entire words. Thousands of characters and symbols were used to represent
the words, needs, and lives of early civilizations.
Memorizing of thousands of
unique hieroglyphic symbols was a difficult task, so only the most highly
educated priests and scholars were experts.
The Latin alphabet, also called
the “Roman alphabet”, is the most widely used alphabetic writing system in the
world today. This is the system on which the English alphabet is based.
6
Burney Crouss went to school to
study the sounds of nature. For 20 years he has recorded the sounds animals
make. He has recordings of animal sounds from all over the world.
Burney has made a record of animal songs. It all began when he took some of the
sounds and put them together. Last year, he put together a song he called
«Jungle Shoes.» It turned out great.
Burney makes the music by
taking part of his animal noises and saving them on a computer. He makes each
sound play when a key is pressed. Then he asks other musicians to play the keys
into songs. Burney believes in working to save nature. He thinks that more
people need to take care of our world. The sounds of nature are quickly
disappearing.
When he recorded whales in Alaska, he could
hear the sound of oil well drilling from fifteen to twenty miles away. It was
very loud. He says his goal is to save nature sounds so his children will be
able to hear them.
7
Half the human beings who have
ever died, perhaps as many as 45 billion people, have been killed by female
mosquitoes. Mosquitoes carry more than a hundred potentially fatal diseases
including malaria, yellow fever and elephantiasis. Even today, they kill one
person every twelve seconds. Amazingly, nobody had any idea that mosquitoes
were dangerous until the end of the nineteenth century. In 1877, the British
doctor Sir Patrick Manson proved that yellow fever was caused by mosquito
bites.
Seventeen years later it occurred to him that malaria might also be caused by
mosquitoes. He encouraged his pupil Ronald Ross to test the hypothesis. Ross
was the first person to show how female mosquitoes transmit the parasite.
Manson went one better. To show that the theory worked for humans, he infected
his own son – using mosquitoes carried in the diplomatic bag from Rome.
8
Some paintings found in
different caves around the world are recognized as the work of Stone Age
artists. But what was the purpose of the paintings? Why were they hidden in a
dark room where there is no evidence that cave people lived?
No one really knows, but there
is one theory that makes great sense. It is called the theory of Sympathetic
Magic. According to this, the cave people believed that if they could make a
likeness of an animal, they could put a spell over it. This spell would give
the tribe power over the live animal.
Stone Age existence depended on
killing animals — for food, clothing, and even weapons and tools. The
animals were large and fierce; the cave people had only the most simple
weapons. Hunters had to be brave and fearless. They needed more than a spear or
club; they needed all the magic they could get. The magic could help the
hunters catch the animals.
9
Mountain
gorillas live in the dense forests of Central Africa and are one of man's
closest relations in the animal kingdom. They live in family groups and spend
the day eating plants. Every evening each gorilla builds a nest to sleep in.
Mountain
gorillas are black, and have evolved very thick fur so that they can withstand
the cold mountain air. An adult male is called a silver back because of the
silver-grey fur that grows on its back when it reaches maturity. A silverback
is about the same height as an average man but heavier. Females are much
smaller.
The
destruction of their natural habitat is a serious threat to gorillas. Illegal
hunting and trading are also a problem. Tourism helps to finance the ongoing
efforts to save this endangered species. A few companies organise gorilla
safaris so that people can see these amazing creatures at first hand. Some of
the money from these tours goes to wild life organisations to protect the
gorillas.
10
Half the human beings who have
ever died, perhaps as many as 45 billion people, have been killed by female
mosquitoes. Mosquitoes carry more than a hundred potentially fatal diseases
including malaria, yellow fever and elephantiasis. Even today, they kill one
person every twelve seconds. Amazingly, nobody had any idea that mosquitoes
were dangerous until the end of the nineteenth century. In 1877, the British
doctor Sir Patrick Manson proved that yellow fever was caused by mosquito
bites.
Seventeen years later it occurred to him that malaria might also be caused by
mosquitoes. He encouraged his pupil Ronald Ross to test the hypothesis. Ross
was the first person to show how female mosquitoes transmit the parasite.
Manson went one better. To show that the theory worked for humans, he infected
his own son – using mosquitoes carried in the diplomatic bag from Rome.
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