Lecture 12 - Chapter 56 - Conservation Biology and Genetics

Lecture 12 - Chapter 56 - Conservation Biology and Genetics...

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Conservation Biology and Genetics Chapter 56 Overview: Striking Gold 1.8 million species have been named and described Biologists estimate 10–200 million species exist on Earth Tropical forests contain some of the greatest concentrations of species and are being destroyed at an alarming rate Humans are rapidly pushing many species toward extinction Ecology Physiology Molecular biology Genetics Evolutionary biology Conservation genetics Conservation biology is a young field that integrates: The depressing news Nearly 50% of land surface has been altered by humans About 75% of marine fisheries are fully exploited or overexploited We have increased atmospheric CO 2 concentrations by 30% Rate of species loss may be as much as 1000x higher than at any point in the past 100,000 years •Conservation biology has grown rapidly in response these trends and biodiversity loss
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Genetic diversity in a vole population Species diversity in a coastal redwood ecosystem Community and ecosystem diversity across the landscape of an entire region •Genetic diversity –Genetic variation within and between populations •Species diversity –The number and relative abundance of species •Ecosystem diversity –The diversity of habitats, communities and ecological processes Three Levels (scales) of Biodiversity Three Threats to Biodiversity Most species loss can be traced to four major threats: 1. Habitat destruction 2. Introduced species 3. Overexploitation 4. Disruption of “interaction networks” 1. Habitat Destruction: Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere About 93% of coral reefs have been damaged by human activities 1985 1985 1996 1996 Examples : Wisconsin, prairie occupies <0.1% of its original area Fig. 56-2 Coastal zone modifications Rainforest clear cutting
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Habitat Destruction California Gnatcatcher Coastal sage scrub habitat Fig. 56-7 2. Introduced Species Introduced species are those that humans move from native locations to new geographic regions Without their native predators, parasites, and pathogens, introduced species may spread rapidly Introduced species that gain a foothold in a new habitat usually disrupt their adopted community Causes of introduction differ (a) Brown tree snake (b) Kudzu Accidental Arrived in Guam as a stowaway Intentional Introduced as a hwy ground cover in South
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Zebra Mussel ( Dreissena polymorpha ) - clogs water intake pipes and fouls surfaces - out competes native mussels in NA - clears plankton (food) for resident pops - few predators (e.g. diving ducks, freshwater drum, carp, &sturgeon) -estimated$3 billion
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This note was uploaded on 10/03/2009 for the course BISC 120 at USC.

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Lecture 12 - Chapter 56 - Conservation Biology and Genetics...

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