A species becomes extinct when its death rate is continually greater than its birthrate.

Record of Destruction

Its hard to tell exactly how many species are becoming extinct when we don’t know exactly how many there were in the first place.  Even a handful of trees in a rainforest eco-system could contain numerous previously unidentified invertebrates. Between 1.4 and 1.8 million species have already been officially identified.  An article in Science Magazine published in January, 2013, estimated that there are two million to eight milliion species.

With the human race multiplying, the destruction of tropical rain forests with the equivalent of
36 football fields of rain forest being destroyed every minute and the probable loss of approximately 800 square miles of wild habitat each day to human needs - it is hardly surprising that there are so many endangered species of animals and plants.

It is interesting to look at the way in which the disappearance of animal species in ever-increasing numbers is related to the steady increase in the size of the world's human population over the past three hundred years. The figures look like this:

17th Century

By the middle of the century there were about 450 million humans on earth and 7 animal species became extinct.

18th Century

550 million humans on earth and 11 more species became extinct by mid-century.

19th Century

By 1850 the human population had increased to 900 million and 27 species were lost.

20th Century

In October 1999 the world population hit 6 billion (6,000 million).  Over the 20th century 157 known animal species became extinct. 

21st Century

To date there are over 7.2 billion people on earth.  This is set to peak at 9 or 10 billion.  So far approximately 10 animal species have become extinct. Since we only know a small proportion of the species that exist, this number is likely to be much higher.

Read More: The International Union for Conservation of Nature

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