In biology, the complete disappearance of a species from the planet. Extinctions occur when a species becomes unfit for survival in its natural habitat usually to be replaced by another, better-suited species. MORE
Contamination of the environment as a result of human activities. The term pollution refers primarily to the fouling of air, water, and land by wastes (see air pollution; water pollution; solid waste).
In biology, the process by which a living organism produces other organisms more or less similar to itself. The ways in which species reproduce differ, but the two main methods are by asexual reproduction and sexual reproduction.
American zoologist who conducted extensive studies of mountain gorillas in Rwanda. Her research brought about a new understanding of the behavior and habitat of the gorilla and supported conservation efforts in Africa.
Russian zoologist and immunologist who was a pioneer of cellular immunology and shared the Nobel Prize for Physiology or Medicine in 1908 with Paul Ehrlich for the discovery of the innate immune response.