Biodiversity includes the genetic, species, and ecological variety in populations and communities.
Approximately 1.7 million species have been named, so far, but biologists estimate that somewhere between 3 million to 50 million may exist, 95 percent of which are plants and invertebrate animals (those without backbones).
Biodiversity provides food, medicines, ecological services, and aesthetic and cultural benefits to humans.
The main human threats to biodiversity can be summarized by HIPPO: habitat destruction, invasive species, pollution, population growth (human), and overharvesting.
The Endangered Species Act is one of the most effective environmental laws in United States history, but also is among the most disliked because it can limit property rights and economic benefits where species are threatened or endangered.
Endangered species are those considered in imminent danger of extinction, while threatened species are those likely to become endangered in the foreseeable future.
A few charismatic, flagship, or politically powerful species get the vast bulk of funding for protection and recovery programs, while ordinary endangered species get little attention.
Reauthorization of the endangered species act has been highly controversial. Environmentalists generally want to see it strengthened, while property rights advocates and resource developers want to see it weakened or eliminated entirely.
Zoos can be educational and entertaining while still serving important wildlife conservation and scientific functions. Still, there are limits to the numbers and types of organisms we could maintain under captive conditions. Saving biodiversity in the wild may be the most economical and effective conservation strategy.
