Summary of Chapter Concepts

The value of biodiversity arises from social, economic, and ecological considerations. Instrumental values represent the material benefits that species and ecosystems provide to humans including food, medicines, water filtration, and pollination. Intrinsic values recognize that species and ecosystems are valuable regardless of any benefit to humans.

Although extinction is a natural process, its current rate is unprecedented. Historically there have been five mass extinctions, each followed by continued speciation. The current rate of species extinction is higher than background rates, which suggests that we may be in the early stages of a sixth mass extinction. Many species are also experiencing a rapid decline in genetic diversity, although efforts are being made to preserve the genetic diversity of livestock and crops.

Human activities are causing the loss of biodiversity. One of the most important factors contributing to species declines is the loss of habitat. Other impacts include overharvesting, introducing exotic species, and polluting the environment with contaminants. Global warming and global climate change present a rising threat. Some changes have already occurred and species may not be able to accommodate more substantial climate shifts in the future.

Conservation efforts can slow or reverse declines in biodiversity. Major efforts are being made to respond to the decline in biodiversity. Increasing amounts of terrestrial and marine habitat are being protected, harvest regulations are being adjusted to slow population declines, and species approaching extinction are being reintroduced where high-quality habitat exists and the threats can be reduced.