The word “ecology” comes from two Greek words which mean “household” and “study”. In “The Riddle of the Universe”, he applied the term “ecology” to the “relation of the animal both to its organic as well as its inorganic environment”.

For many years, ecology was an obscure brunch of biology. In the late twentieth century, however, as environmentalism became a popular movement, ecology moved to the forefront of public opinion and also rose to prominence as a discipline. Some of the late twentieth and early twenty-first centuries' thorniest problems - expanding populations, food scarcity, and environmental pollution - were and are essentially the problems of ecology.

Ecologists study organisms in various kinds of environments by looking for patterns of interaction. An organism's environment includes both other organisms and physical surroundings. It involves relationships among individuals within a population and among individuals of different populations. These interactions among individuals, among populations, and between organisms and their environment from ecological systems, or ecosystems. (161)

You don't see many birds in winter. Most have left your area. Those that stay are not as active. Activity uses energy that is needed to keep warm.

The worst problems for birds in winter are getting enough heat and holding on to the heat once it is made. These are problems for all the birds. But it is especially true for very small ones. They cannot find enough food. The weather stays so cold for so long that they cannot eat enough to keep alive. But birds have many ways of fighting the cold.

You shiver to keep warm. The heat that you make is made mostly in your muscles. The muscles make more heat when they are active. So one way of keeping warm is to move about, use your muscles. Another way is to shiver. When your body needs heat, the muscles tighten and loosen quickly. They become active. Just as you shiver to keep warm, so do birds. (162)

Much of what we know about the history of humankind has come to us through writing. Indeed, most of what we know about human life prior to writing - prior to "written history" - is based on speculations and guesswork. For thousands of years, people have used writing to make records of their lives. They have written laws and treaties to maintain order and peace; they have made written agreements for trading goods and kept records of seasons, crops, planting and hearvests. They have observed and written the explanations of natural phenomena like day and night, winter and summer, water and earth, moons and stars, animals and plants.

They have used writing to try to understand spiritual life and to create religions. They have created educational books to teach their young and they have written about their feelings and emotions in poetry, drama, song and story. (147)

Because birds have such fine eyesight, they are hard to approach. Bird watchers use binocularis to study birds. One way to watch them up without using binocularis is to go to a place they go to often. Sit still, keep quiet, and wait until they come. Soon they will be doing things all round you.

You may get too close to the animals you are watching. Always stay at a distunce that is easy for them and for you. Do not disturb nesting birds. And never approach an animal that is with its young. Wild animal parents can be very protective. If you come upon a baby animal that looks like it's alone, let it be. Mother may be watching you from a hiding place nearby.

Do not touch or corner a wild animal. Never follow an animal into places you don't know. There is no such thing as a tame wild animal.(153)

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. (162)

What was the family life like in ancient Scandinavia? Most Viking male population was allround handymen, but some had special skills. You could find boat-builders, potters, leatherworkers and smiths. Most Viking men knew how to handle a boat and most of them could fight if they had to, to protect the family or to support their chief.

Women were known to work at home and bear responsibility for household chores. They baked bread, did spinning and weaving, turning sheep wool into cloth and items they would wear. They looked after their children, made the family's clothes and cooked two meals which most families had daily. On the farm, women milked the cows and made cheese. Viking children helped their parents and did not attend school. However, they were not illiterate. They learned Viking history, religion and law from stories and songs, not from books. By the age of 15 or 16 they were considered adults. It was common for girls' fathers to choose their future husbands. (166)

In the late 1500s, in Italy, a man named Andrea Amati set out to create a beautiful instrument. He determined it should have an hourglass-shaped body with four strings attached to it. It should also have a beautiful neck and fingerboard. The instrument was called the violin and it went on to be one of the most popular instruments of all time.

The people who played the violin were called violinists. To play the violin, they used a stick, called a bow. The bow was made of wood and horse hair. As the horse hair brushed across the strings, it caused them vibration. The vibration was how the strings made music.

The violin became part of a family of instruments called string instruments. Its cousins were the viola and cello. Of all the string instruments, the violin had the highest voice. With its beautiful voice, it could be used to convey all sorts of emotion in music.  (157)

 When beauty queens of former times and nowadays are compared, it is obvious that they have become much slimmer. An appearance which was considered normal 50 years ago is rare today. In order to be as slim as fashion demands, they are compelled to go around starving.

Most women today feel that they are under an obligation to be slim. This results in an increasing number of them getting eating disorders. Cultural idealization of thinness, which is in fact anorexia, and youthfulness have both contributed to eating disorders affecting diverse groups of population.

Food containing a lot of sugar and fat dominates the market and if eaten regularly and not in moderation it can soon cause an increase in weight.  A person can get problems with self-image and eating through ideals which are spread by mass media. Many young women with a normal body shape develop an idea that they are overweight and start slimming even though it is harmful for them.(162)

Islands that appear and disappear are certainly part of the world’s legends. But in 1963, with the aid of cameras and scientific observers, some of those legends were given a solid basis of fact. For example, on November 14, 1963, a kind of miracle occurred. An island was born.

On that day a fishing boat sailed into waters that were boiling and rolling and foul with a strong smell. The world still had a hard time believing the miracle that was to occur. It was the first time that scientists were to witness the unexpected birth of an underwater island.

First the engineer, then the captain, and at last the cook were aware of the awful smell and the peculiar roll of the sea. But it was the cook who first noticed the smoke. He thought there was a ship in trouble somewhere on the seas. (146)

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 seeds are borne in flowers or cones. (151)