Download Ecosystem Diversity 1. Biodiversity • What is biodiversity? o Variety

Ecosystem Diversity
1. Biodiversity
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What is biodiversity?
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Variety of different species (species diversity), genetic variability among
individuals within each species (genetic diversity), variety of ecosystems
(ecological diversity), and functions such as energy flow and matter
cycling needed for the survival of species and biological communities
(functional diversity)
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Why is it important?
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Variety provides us with food, wood, fibers, energy, raw materials,
industrial chemicals and medicines, which pour hundreds of billions
dollars into the world economy each year
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Also provides us with free recycling, purification and natural pest control
services
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Every species today...
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Contains genetic information that represents thousands to millions of
years of adaptation to the earth’s changing environmental conditions
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Is the raw material for future adaptations
Loss of biodiversity...
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Reduces the availability of ecosystem services
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Decreases the ability of species, communities and ecosystems to adapt to
changing environmental conditions
2. Natural Selection
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What is natural selection?
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Process by which a particular beneficial gene (or set of genes) is
reproduced in succeeding generations more than other genes
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Result: population that contains a greater proportion of organisms better
adapted to certain environmental conditions
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Types
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Directional – changing environmental conditions cause allele frequencies
to shift so individuals with traits at one end of the normal range become
more common than midrange forms
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Stabilizing – tends to eliminate individuals on both ends of the genetic
spectrum and favor individuals with an average genetic makeup
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Diversifying – environmental conditions favor individuals at both extremes
of the genetic spectrum and eliminate or sharply reduce numbers of
individuals with normal or intermediate genetic traits
3. Evolution
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What is evolution?
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Change in the genetic makeup of a population of species in successive
generations
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If continued long enough, it can lead to the formation of a new species
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*Populations, not people, evolve
4. Ecosystem Services
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What are ecosystem services?
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Natural services or capital that support life on Earth and are essential to
the quality of human life and the functioning of the world’s economies
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Without the services performed by diverse communities of species, we
would be starving, gasping for breath and drowning in our own waste
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*See Figure 4-34 on page 92 in textbook