Wilson estimated that 30,000 species per year (or three species per ... With enormous, cheap energy at its disposal, the human population grew rapidly from 1 billion in 1800 to 2 billion in 1930, 4 ...

either species wins based on population densities; or 4) coexistence occurs. Species can survive together if intra-specific is stronger than inter-specific competition. This means that each ...

The U.S. Fish and Wildlife Service is opening a second comment period as they work to list the monarch butterfly on the ...

How are Endangered Species Identified ... A series of quantitative criteria is measured for inclusion in these categories, including: reduction in population size, geographic range size and ...