The correct option is Robert May.
Explanation
The inventory of Earth's species is incomplete. While the International Union for Conservation of Nature (IUCN) has documented slightly more than 1.5 million species, the total number of species existing on Earth is estimated to be much higher. Various scientists have proposed estimates ranging widely, but statistical methods are used to derive more accurate figures.
Detailed Analysis
- Robert May: He proposed a more conservative and scientifically sound estimate compared to extreme ranges (which went as high as 20 to 50 million). May places the global species diversity at approximately 7 million. Based on this estimate, only about 22 % of the total species have been recorded so far.
- Edward Wilson: He is a renowned sociobiologist who popularized the term "biodiversity" to describe the combined diversity at all levels of biological organization, but he is not primarily cited for the 7 million estimate.
- Ernst Mayr: Known as the "Darwin of the 20th Century," he made significant contributions to evolutionary biology and the definition of the biological species concept, not the global species count estimate.
- Charles Darwin: He is the father of the theory of evolution by natural selection, predating modern global species inventory estimates.
Key Takeaway: Robert May provided the widely accepted scientific estimate of approximately 7 million global species, highlighting that a vast majority of species remain undiscovered.