Principles of Biology II BIOL 2108

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Principles of Biology IIBIOL 2108
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Theme Scientific Method
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A hypothesis may be verified, but never proven!
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Proof (Geometry)
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Biological hypothesis

• Homunculus hypothesis
• Reproduction by fully formed embryo
• in father or mother ??
• Discovery of sperm ovum verification !
• living cells could contain homunculi

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Biological hypothesis

• Homunculus hypothesis
• Sperm ovum later shown NOT to contain homunculi
• Chromosomes, DNA instead
• Hypothesis FALSIFIED !

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LIMITS of SCIENCE

• Science studies phenomena that are
• observable,
• objectively
• quantifiable,
• measurable
• repeatable.

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LIMITS of SCIENCE

• Science can NOT address questions of Religion,
  Philosophy, Arts.
• Religion.
• Is there a god? What is nature of God?
• Philosophy.
• What is justice? Is capital punishment "cruel
  and unusual?"
• Arts.
• Is jazz good music?
• Should DaVinci have painted a background in the
  Mona Lisa?

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Theme Evolution Classification

• Living things have evolved and diversified from
  ancestors that lived in the past.

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Classification reflects Relationship
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Theme Living systems are organized on several
levels
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Theme Organisms interact with their environments

• Flow of energy
• Cycling of matter
• Carbon cycle
• Nitrogen cycle

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Theme Structure Function are correlated

• Populations have evolved and adapted to the
  physical and biological environment.

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Theme Feedback mechanisms

• Feedback mechanisms regulate physiological
  processes
• Negative feedback stabilizes systems.
• Positive feedback produces runaway increase
  unless there is an endpoint.