From the time when human beings first began to grow crops and live in settled communities, their numbers increased fairly steadily until about 1700. Shortly after this the industrial revolution led to a doubling of the population in about 100 tears. In 1800 the world‘s population was around one billion.
By 1990, the numbers had risen to over five billion people will be looking for shelter and food somewhere on the earth. One species cannot increase explosively without affecting all the others. Since about 1700, at least 300 species of vertebrates have become extinct. Now a days we can observe in detail most creatures that are being lost, and the estimate is between 50 and 100 species a day. If the present trend continues at least a quarter of all living things will have disappeared before the human population reaches its levels out, probably in the middle of 21st century.
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