ABSTRACT
Biodiversity, the diversity of life from genes to species to ecosystems, is found on almost all parts of Earth’s surface but is greatest in species terms in the tropics. Arguably, there are 5 ± 3 million species on Earth, only about 1.5 million of which have been named, with arthropods being the largest group. Tropical rain forests and coral reefs are the centers of biodiversity for the terrestrial and marine environments. Conservation, the protection of organisms and their habitats, is essential because of the increasing threats to biodiversity from large-scale environmental change and more recently climate change. Conservation biology is the science developed to protect biodiversity and ecosystems. The impact of environmental change is becoming so severe that many consider that a large proportion of the world’s species are threatened with extinction. Current extinction rates are increasing, and extinctions, previously mostly on islands, are becoming more prevalent in continental landmasses.
