Biology Ii Final: Ch. 56 -Conservation Biology And Global Change

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56.1 Human activities Threaten Earths Biodiversity

Back 1

- Extinction is a natural phenomenon
- high rate of extinction that is responsible for todays biodiversity crisis
- can't estimate number of species currently existing, can't determine exact rate of species loss

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56.1 Three levels of biodiversity

Back 2

Three main levels
1) Genetic Diversity
2) Species diversity
3) Ecosystem diversity

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56.1 Three levels of biodiversity

Genetic Diversity

Back 3

- no only the individual genetic variation w/in a pop, but also genetic variation between pop associated w/ adaptations

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56.1 Three levels of biodiversity

Species Diversity

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- more species are lost to extinction, species diversity decreases

- Endangered Species: one that is "in danger of extinction throughout all or significant portion of its range"

- Threatened Species: likely to become endangered in the near future

- may be local (species may be lost in one river system, but survive in an adjacent one)

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56.1 Three levels of biodiversity

Ecosystem Diversity

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- Variety of biosphere's ecosystems
- interactions between pop
- local extinction of one species can have a neg impact

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56.1 Biodiversity and Human Welfare

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- E.O Wilson: biophilia - sense of connection to nature and all life. Belief that other species are entitled to life is a pervasive them of many religions

- minister of Norway: must consider our plant to be a loan from our children, not a gift from our ancestors"

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56.1 Biodiversity and Human Welfare

Benefits of Species and Genetic Diversity

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- improved crop qualities (disease resistance)
- prescription drugs, deriving from plants
- loss of species means loss of unique genes - useful proteins

Front 8

56.1 Threats to Biodiversity

4 major threats

Back 8

Threats posted by human activities:

1) habitat loss
2) introduced species
3) Overharvesting
4) global change

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56.1 Threats to Biodiversity

Habitat Loss

Back 9

- alteration of habitat
- brought about by: agriculture, urban development, forestry, mining, pollution
- No alternative habitat, or species is unable to move - habitat loss may mean extinction
- habitat fragmentation leads to species loss

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56.1 Threats to Biodiversity

Introduced Species

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- non-native or exotic species humans move intentionally or accidentally from native's location
- travel by ship or plane
- new species, free from predators & competition, may spread rapidly throughout new region
(snakes)

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56.1 Threats to Biodiversity

Overharvesting

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- human harvesting of wild organisms at rates exceeding ability of populations to rebound
- large organisms w/ low reproductive rates: whales, elephants.

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56.1 Threats to Biodiversity

Global Change

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- alterations in climate, atmospheric chemistry, broad ecological systems that reduce capacity of Earth to sustain life
- acid rain

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56.2 Pop conservation

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- When pop drops below a minimum viable population (MVP) size, its loss of genetic variation due to nonrandom mating and genetic drift can trap it in an extinction vortex.

- The declining-pop approach focuses on the environmental factors that cause decline, regardless of absolute pop. size. follows a step-by-step conservation strategy.

- Conserving species often requires resolving conflicts between the habitat needs of endangered species and human demands

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56.3 Landscape and regional conservation help sustain biodiversity

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- The Structure of a landscape can strongly influence biodiversity. As habitat fragmentation increases and edges become more extensive, biodiversity tends to decrease. Movement corridors can promote dispersal and help sustain populations.

- Biodiversity hot spots are also hot spots of extinction and thus prime candidates for protection. Sustaining biodiversity in parks and reserves requires management to ensure that human activities in the surrounding landscape do not harm the protected habitats. The zoned reserver model recognizes that conservation efforts often involve working in landscapes that are greatly affected by human activity

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56.4 Earth is changing rapidly as result of human action

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- agriculture removes plant nutrients from ecosystems, so large supplements are usually required. nutrients in fertilizer can pollute groundwater and surface-water aquatic ecosystems, where they can stim excess algal growth (eutrophication)

- The release of toxic wastes has polluted the environment w/ harmful substances that often persist for long periods and become increasingly concentrated in successively higher trophic levels of food webs (biological magnification)

- Because of burning of wood and fossil fuels and other human activities, atmospheric concentration of CO2 and other greenhouse gases has been steadily increasing. The ultimate effects include significant global warming and other changes in climate.

- The ozone layer reduces the penetration of UV Radiation through the atmosphere. Human activities, notably the release of chlorine-containing pollutants, have eroded the ozone layer, but gov't policies are helping to solve the problem

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56.5 Sustainable Development can improve human lives while conserving biodiversity

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- goal of sustainable biosphere initiative is to acquire the ecological information needed for the development, management, and conservation of Earth's resources.
- Costa rica's success in conserving tropical biodiversity has involved a partnership among the gov't, other organizations, and private citizens. Human living conditions in costa rica have improved along w/ ecological conservation.

- By learning about biological processes and diversity of life, we become more aware of our close connection to the environment and the value of other organisms that share it.