CAPF Exam Human Expansion and Loss of Species Are Important Topics for

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The Loss of Species

The expansion of human activity is destroying-habitats and causing the extinction of plant and animal species at an accelerating rate. This is probably the most serious of all ecological problems. There are probably 10 to 30 million species in existence, mostly undiscovered as yet. In the 300 years to 1970 humans probably caused the extinction of about 300 species. Some biologists estimate that we are now losing 17500 species every year, about 2 every hour. ln the next 20 years, one million plant and animal species could be made extinct. At this rate, in the next 50 years half of all species could be lost. We have entered a period of rapid extinction unlike any since 60 million years ago when the dinosaurs suddenly died out. The result will be the weakening of the life-support systems of the planet, because it is the diversity and complexity of life forms which maintains these systems, for example recycling nutrients and maintaining the atmosphere. We are also losing many varieties of food plants because it suits corporations to sell mostly the few types which maximize their profits. Because the seeds they sell are “hybrids” the resulting plants will not yield a seed that produces a good crop, meaning that farmers can՚t save their own seed and have to buy more seed from the big seed companies every year. The seeds sold are the types that thrive only when given many energy-intensive inputs such as fertilizer and water. Because of this trend, within one generation, large numbers of plant varieties that used to be kept in existence by farmers saving their own seed are being lost as farmers all around the world are now mostly buying the same few varieties from the seed corporations.

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