Ecosystems, Populations, and biodiversity

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Ecosystems, Populations, and biodiversity

• SCI 7724

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Case Study Costa Rica Cloud forest
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What is evolution, really?
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Natural selection
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Natural selection works on POPULATIONS
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Evolution can generate biodiversity
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What is speciation and how does it happen?
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Population separation

• Allopatric speciation

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• Sympatric speciation

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Phylogenetic trees
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Mass extinction events

• Most extinction occurs gradually background
  extinction rate
• Mass extinctions can wipe out 50-95 of
  biodiversity
• 65 mya- K-T event
• 250 mya- 75-95 of species extinct- volcano?

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The sixth mass extinction

• http//www.well.com/davidu/extinction.html

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Levels of ecological organization

• Biosphere
• Ecosystem
• Community
• Population
• Individual

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Niches

• Whats so important about niches?

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Population size

• How is it calculated/estimated?
• Why is it important?

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Population density

• How is it calculated/estimated?
• Why is it important?

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Population distribution

• How is it calculated/estimated?
• Why is it important?

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Sex ratios and age structure

• Why does it matter?

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How populations change over time
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Limiting factors and carrying capacity
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R- and K-selected species
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Conservation of Biodiversity

• Cloud forest

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Interpreting graphs