Key Terms

adaptive radiation

rapid branching through speciation of a phylogenetic tree into many closely related species

biodiversity

variety of a biological system, typically conceived as the number of species, but also applying to genes, biochemistry, and ecosystems

biodiversity hotspot

concept originated by Norman Myers to describe a geographical region with a large number of endemic species and a large percentage of degraded habitat

bush meat

wild-caught animal used as food (typically mammals, birds, and reptiles); usually referring to hunting in the tropics of sub-Saharan Africa, Asia, and the Americas

chemical diversity

variety of metabolic compounds in an ecosystem

chytridiomycosis

disease of amphibians caused by the fungus Batrachochytrium dendrobatidis; thought to be a major cause of the global amphibian decline

DNA barcoding

molecular genetic method for identifying a unique genetic sequence to associate with a species

ecosystem diversity

variety of ecosystems

endemic species

species native to one place

exotic species

(also, invasive species) species that has been introduced to an ecosystem in which it did not evolve

extinction

disappearance of a species from Earth; local extinction is the disappearance of a species from a region

extinction rate

number of species becoming extinct over time, sometimes defined as extinctions per million species–years to make numbers manageable (E/MSY)

genetic diversity

variety of genes in a species or other taxonomic group or ecosystem, the term can refer to allelic diversity or genome-wide diversity

heterogeneity

number of ecological niches

megafauna

large animals

secondary plant compound

compound produced as byproducts of plant metabolic processes that is usually toxic, but is sequestered by the plant to defend against herbivores

species-area relationship

relationship between area surveyed and number of species encountered; typically measured by incrementally increasing the area of a survey and determining the cumulative numbers of species

tragedy of the commons

economic principle that resources held in common will inevitably be overexploited

white-nose syndrome

disease of cave-hibernating bats in the eastern United States and Canada associated with the fungus Geomyces destructans