
Mineral Cycles
Although the biosphere is mainly composed of hydrogen, carbon, nitrogen and oxygen, other elements are essential constituents of living matter. Notable among them are phosphorus and sulfur

Mineral Cycles
Although the biosphere is mainly composed of hydrogen, carbon, nitrogen and oxygen, other elements are essential constituents of living matter. Notable among them are phosphorus and sulfur

The Human Population
In the short span of his existence man has come to consume more food than all other land animals put together. This raises the question of how many men the earth can support

Living Records of the Ice Age
The missing snakes of Ireland, the peat of the English Channel and the fishes of Great Salt Lake are among the biogeographer's clues to the events of the Pleistocene