Page 322 - Environment: The Science Behind the Stories

Conclusion

Data from scientists worldwide confirm what any naturalist loss. This loss matters, because human society cannot func-
who has watched the habitat change in his or her hometown tion without biodiversity’s pragmatic benefits. Conservation
already knows: From amphibians to zebras, biological diver- biologists are rising to the challenge of conducting science
sity is being lost rapidly within our lifetimes. This erosion aimed at saving endangered species, protecting their habitats,
of biodiversity threatens to result in a mass extinction event recovering populations, and preserving and restoring natural
equivalent to those of the geologic past. Habitat alteration, ecosystems. The innovative strategies these scientists are pur-
invasive species, pollution, overharvesting of biotic resources, suing hold promise to slow, and perhaps reverse, the loss of
and climate change are the primary causes of biodiversity biodiversity on Earth.

Reviewing Objectives

You should now be able to: • Wild species are sources of food, medicine, and economic
development. (pp. 309–311)
Characterize the scope of biodiversity on Earth • Many people feel that we have a psychological need to
• Biodiversity can be thought of at three levels: species diver- connect with the natural world, as well as an ethical duty to
sity, genetic diversity, and ecosystem diversity. (pp. 294–296) preserve nature. (pp. 311–312)

• Some taxonomic groups (such as insects) hold far more Assess the science and practice of conservation biology
diversity than others. (pp. 296–297)
• Conservation biology studies biodiversity loss and seeks
• Roughly 1.8 million species have been described so far, but sci- ways to protect and restore biodiversity. (p. 312)
entists agree that the world holds millions more. (pp. 296–297)
• Conservation biologists integrate research at the genetic, popu-
• Diversity is unevenly spread across different habitats, lation, species, ecosystem, and landscape levels. (pp. 312–313)
biomes, and regions of the world. (pp. 297–298)
Analyze efforts to conserve threatened and
Understand today’s extinction crisis in geologic context
endangered species
• Species have gone extinct at a background rate of roughly • The U.S. Endangered Species Act has been largely
one species per 1–10 million species each year. Most spe- effective, despite debate over its merits and limitations in
cies that have ever lived are now extinct. (p. 299)
funding. (p. 314)
• Earth has experienced five mass extinction events in the • CITES and the Convention on Biological Diversity are major
past 440 million years. (p. 299)
international treaties to safeguard biodiversity. (p. 315)
• Human impact is now initiating a sixth mass extinction. • Modern recovery strategies include captive breeding and
(pp. 300–301)
reintroduction programs. (pp. 315–316)
• Most biodiversity loss consists of a gradual reduction of • Forensics can help us trace products from illegally poached
population sizes and extirpation of populations. (p. 301)
animals. (pp. 316, 318–319)

Evaluate the primary causes of biodiversity loss CHAPTER 11 • Bi odiv ER si T y A nd Cons ER vAT i on Bi ology
Compare and contrast conservation efforts above the
• Habitat loss (through destruction, alteration, or fragmentation) species level
is the main cause of current biodiversity loss. (pp. 301–303) • Charismatic species are often used in popular appeals to

• Pollution, overharvesting, and invasive species are also conserve habitats and ecosystems. (p. 316)
important causes. (pp. 303–307) • Parks and protected areas conserve biodiversity at the
• Climate change is becoming a major cause. (p. 307) landscape level. (pp. 316–317)

• Amphibians are facing a global crisis, probably from a mix • Biodiversity hotspots help prioritize regions globally for
of factors. (p. 307) conservation. (p. 317)
• Ecological restoration efforts are restoring degraded
Specify the benefits that biodiversity brings us ecosystems. (pp. 317, 320)

• Biodiversity supports functioning ecosystems and the • Community-based conservation empowers people to invest
services they provide us. (pp. 308–309) in conserving their local species and ecosystems. (p. 320) 321

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