Discusses the coevaluation of species within ecosystems. This process gives rise to interesting patterns in the total number of species found in a given area, in their relative abundances, and in the overall structure of the local food web. (Author/MA)

Discusses recent fossil evidence indicating that human-like creatures branched off from other primates over four million years ago. Homo sapiens is believed to have appeared only 100,000 years ago. (MA)

Suggests that at least 5,000,000 people are infected by the virus and that within the next five years 1,000,000 new cases will emerge. Describes three distinct infection patterns of the Acquired Immunodeficiency Syndrome that are apparent worldwide. (RT)

Discusses the discovery and varied manifestations of the human immunodeficiency virus infection, and the analysis of the circumstances that made possible the spread of the disease. Indicates that males between the ages of 25 and 45 are the greatest number of patients with the infection. (RT)

Discusses the biological and social effects of the disease on society. States that a crucial issue is protection from discrimination. Explains that infection can be stemmed by education and altered behavior patterns. (RT)

Presented are the three main theories that describe the pattern of evolution of geographic variants of H. sapiens--the multiregional model, the out-of-Africa model, and the gene-flow or hybridization model. The contributions of geneticists, paleoanthropologists, and the history of fossils are included. (KR)