GEO 131 Lecture Notes - Lecture 1: Vulnerable Species, Natural Capital, Ecosystem Approach
2 Apr 2019
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Background extinction rate (ber) - scientists estimated a low average rate of extinction that persisted throughout most of the history of life on earth. Before humans became a prominent species, ber was roughly one extinct species per million species per year, which amounted to an extinction rate of about. 0. 0001% per year (i. e. , if there were 10 million species on the earth, about 10 of them, on average, would go extinct every year) Earth"s biodiversity - balance between formation of new species and extinction of existing species. With the passing of many hundreds of millions of years, earth"s biodiversity has increased. Earth has experienced at least three and probably five mass extinctions when 25 to 95% of the world"s species appear to have become extinct. Following mass extinction, biodiversity eventually returned to equal or higher levels, but each recovery required millions of years.
