1000 Great Events [antikvár]

Introduction This book describes one thousand of the greatest events that have occurred in the history of civilization. Some of them are great advances in the history of man -great medical or scientific discoveries for example. Others are disasters caused by man's inhumanity to man - such as the Thirty Years' War, or the dropping of the atom bomb - not 'great' but unfortunately important historical events. Many of the events in this book are cultural milestones, famous books or paintings. And many events may not seem important to you at all: popular music or social customs may not seem to be as significant as revolutions and wars, but they are nevertheless useful pointers. This book covers the last seven thousand years of the world's history. This seems like a long time, but it is quite brief compared with the four million years or so that man has walked the earth. Yet man himself is a real newcomer on the earth, although he has had more impact on his surroundings than any other creature. The origins of the earth It is estimated that our planet was born as much as 4,500 million years ago. It has often been stated in the past that the world began as a hot, fiery ball. This is no longer thought to be true. A modern idea suggests that the earth and its satellite, the moon, were formed by the cold accumulation and compaction of gas and dust particles in space. As the earth compacted, enough heat was generated to start certain materials breaking down. These materials, known as radioactive elements, released even more heat. The earth now seems to be cooling down again but at the centre of the planet today the temperature is still estimated to be as much as 2,700°C. You can get some idea of just how hot this is by remembering that water boils at a mere ioo°C. Life begins on earth It is all too easy to take for granted the variety of living creatures, including our- selves, that the earth supports. We should remember, however, that so far as is known at present, earth is the only planet in the solar system to support such a complicated living web of animals and plants and that it took a very long time for the first primitive life to develop. In fact, it was about 1,300 million years after the birth of the earth before the first, tiny, simple, algae-like plants evolved. Before this time, there existed complicated chemical substances and it was not until these were able to reproduce themselves that they could be considered as living things. Traces of these first living forms can be found fossilized in rocks 3,200 million years old in southern Africa. It was not until 600 million years ago, at the beginning of a period in the earth's long history that we call the Cambrian, that there seems to have been a sudden upsurge in the variety and numbers of animals and plants, although life was still mainly represented by two groups of sea animals - trilobites and brachiopods. Trilobites are now extinct but they were related to insects and spiders. Brachiopods are similar in appearance to cockles, although they are not related, and there are still members of this group alive today. There were no vertebrates (animals with backbones) alive at this time. It took yet another 100 million years before the first fishes appeared in Ordovician times, and a further 100 million years before they became well established in the Devonian period. It was at this time too that the land began to be colonized by the first primitive pond plants, which could in turn support animals similar to our modern spiders, centipedes and snails. From water to land There were two types of Devonian bony fishes, characterized by having either ray fins or lobe fins. Those with lobe fins, the lung fishes, were able to support their body weight on land and breathe air, so that they were able to withstand periods when tlie lakes dried out during the 4