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Unifying themes connect concepts from many fields of biology.

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  • All levels of life have systems of related parts and biologists study many different types of systems.
  • A system is an organized group of interacting parts.
    • A cell is a system of chemicals and processes.
    • A body system includes organs that interact.
    • An ecosystem includes living and nonliving things that interact.

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  • Structure and function are related in biology.
  • Structure determines function.
    • Proteins with different structures perform different functions.
    • Nerve cells have a different structure and function than red blood cells.
    • Different species have different anatomical structures with different functions.

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  • Organisms must maintain homeostasis to survive in diverse environments.
    • Homeostasis is the maintenance of constant internal conditions. (Ex. Body temperature, blood volume, pH)
    • Homeostasis is usually maintained through negative feedback. Negative feedback systems return a condition to its normal state.
    • Behaviors and adaptations can help

maintain homeostasis.

    • Adaptations are inherited characteristics

that increase chances of survival.

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Can you give examples of adaptations?

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  • Evolution explains the unity and diversity of life.
  • Evolution is the change in living things over time.
    • The genetic makeup of a population of a species changes. Populations evolve not individuals.
    • Evolution can occur through natural selection or adaptations.
    • Adaptations are beneficial inherited traits that are passed to future generations.

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  • Evolution continued:
  • Charles Darwin published the book The Origin of Species in 1859.
    • Species today descended from ancestral species
    • Descent with modification – a process called natural selection.
    • In 1831 Darwin went on a voyage aboard the H.M.S Beagle around the world collecting specimen with his most notable stop being on the Galapagos Islands.

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  • Let’s Review
  • All living things are made up of interrelated systems.
  • The structure or anatomy of all living things is related to the function of those structures.
  • All living things must maintain homeostasis in order to survive.
  • Evolution allows for diversity among organisms, but also proves that organisms are linked by common characteristics.

1.2 Unifying Themes of Biology