End Show Slide 1 of 35 Copyright Pearson Prentice Hall Biology

End Show Slide 2 of 35 Copyright Pearson Prentice Hall 6-3 Biodiversity

End Show 6-3 Biodiversity Slide 3 of 35 Copyright Pearson Prentice Hall The Value of Biodiversity Biodiversity is the sum total of the genetically based variety of all organisms in the biosphere. Ecosystem diversity includes the variety of habitats, communities, and ecological processes in the living world.

End Show 6-3 Biodiversity Slide 4 of 35 Copyright Pearson Prentice Hall The Value of Biodiversity Species diversity is the number of different species in the biosphere. Genetic diversity is the sum total of all the different forms of genetic information carried by all organisms living on Earth today.

End Show 6-3 Biodiversity Slide 5 of 35 Copyright Pearson Prentice Hall The Value of Biodiversity Why is biodiversity important?

End Show 6-3 Biodiversity Slide 6 of 35 Copyright Pearson Prentice Hall The Value of Biodiversity Biodiversity is one of Earth's greatest natural resources. Species of many kinds have provided us with foods, industrial products, and medicines—including painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs.

End Show 6-3 Biodiversity Slide 7 of 35 Copyright Pearson Prentice Hall Threats to Biodiversity What are the current threats to biodiversity?

End Show 6-3 Biodiversity Slide 8 of 35 Copyright Pearson Prentice Hall Threats to Biodiversity Human activity can reduce biodiversity by: altering habitats hunting species to extinction introducing toxic compounds into food webs (biological magnification) introducing foreign species to new environments (invasive species)

End Show 6-3 Biodiversity Slide 9 of 35 Copyright Pearson Prentice Hall Pollution Many forms of pollution can threaten biodiversity. One of the most serious problems occurs when toxic compounds accumulate in the tissues of organisms. DDT, one of the first pesticides, is a good example of this.

End Show 6-3 Biodiversity Slide 10 of 35 Copyright Pearson Prentice Hall Pollution For a long time DDT was considered harmless, and it drained into rivers and streams in low concentrations. However, DDT has two hazardous properties: It is nonbiodegradable, which means that it cannot be broken down by organisms. Once DDT is picked up by organisms, it cannot be eliminated from their bodies.

End Show 6-3 Biodiversity Slide 11 of 35 Copyright Pearson Prentice Hall Pollution When DDT enters food webs, it undergoes biological magnfication. Biological magnification - concentrations of a harmful substance increase in organisms at higher trophic levels in a food chain or food web.

End Show 6-3 Biodiversity Slide 12 of 35 Copyright Pearson Prentice Hall Introduced Species Another threat to biodiversity: Invasive species - introduced species that reproduce rapidly because their new habitat lacks the predators that would control their population.

End Show Slide 13 of 35 Copyright Pearson Prentice Hall 6-3 The type of biodiversity that includes the inheritance information carried by the Earth’s organisms is called a.biological magnification. b.ecological diversity. c.genetic diversity. d.species diversity.

End Show Slide 14 of 35 Copyright Pearson Prentice Hall 6-3 Populations of invasive species tend to a.decrease. b.increase rapidly. c.remain constant. d.increase, then decrease.

End Show Slide 15 of 35 Copyright Pearson Prentice Hall 6-3 By focusing on protecting specific ecosystems, biologists hope to preserve a.global biodiversity. b.biological magnification. c.invasive species. d.habitat fragmentation.

End Show Slide 16 of 35 Copyright Pearson Prentice Hall 6-3 In a food pyramid, biological magnification results in the a.increased amount of a toxic substance in organisms at the lowest level. b.increased amount of a toxic substance in organisms at the highest level. c.decreased number of levels in the food pyramid. d.increased amount of a toxic substance in the surrounding air or water.