EVOLUTION, BIODIVERSITY

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EVOLUTION, BIODIVERSITY EXTINCTION

• LAB 2

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Earth Life

• Earth - formed about 4.5 billion years ago
• Bombarded by asteroids, meteorites, comets
• Volcanic activities, tectonic
• Earliest life forms 3.0-3.5 billion years ago
• Data is gathered from fossil records
• 3 main hypothesis on how life on earth was
• formed

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1.Heterotrophic hypothesis

• Inorganic Organic
• Chemicals compounds cells
• Reproduce
• Use organic compounds as food

UV light
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Other 2

• 2. Extraterrestrial hypothesis
• Microbes evolved into other life forms
• 3. Chemoautotrophic hypothesis
• Atom Large molecules

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Cont

• Through evolution we have different organisms
  and communities over time
• Natural selection process by which
• change occurs
• End result - Evolution

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Fitness

• Ability to survive and reproduce
• Adaptive trait increases fitness
• Maladaptive trait decreases fitness

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Speciation

• Species individuals with similar
• characteristics that can breed
• to give fertile offspring
• Process Speciation
• 2 forms

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Speciation 2 forms

• Allopatric
• Geographic separation
• Different environments
• Different traits
• After long periods cannot inter breed
• Sympatric
• No physical separation
• Competition
• Reproductive isolation
• Eg insects, stickleback fish

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Biodiversity

• Varieties and variability in life forms
• Life on earth is diverse
• 100 million estimated
• 1.5-1.8 million described
• Ecosystem services
• Uneven distribution

poor
average
rich
Equator
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Extinction/Extirpation/Biodiversity

• Disappearance of species
• Extinction from the whole earth
• Extirpation from a specific location
• Biodiversity
• (natural selection evolution speciation)
  -extinction