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Biology:

The Study of LIFE

It’s ALIVE!

Biology: Unit I Characteristics of Life

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Characteristics of Life

1. Based on a Universal Code

    • Info needed to live, grow, and reproduce is in a genetic code written in the molecule of DNA.

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Characteristics of Life

2. Made of Cells

    • Cells are the smallest unit considered fully alive.
  • Organisms may be unicellular or multicellular.

Unicellular – made up of one cell

Multicellular – made up of multiple cells

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3. Grow and Develop

    • Growth - increase in size
    • Develop - change in form during lifetime
    • A single fertilized egg divides again and again and differentiates into cells that look different and perform different functions.

Characteristics of Life

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Characteristics of Life

4. Respond to their Environment

  • Stimulus – any signal to which an organism responds.
    • Undergoing hibernation
    • Undergoing a migration
    • Shedding of Leaves

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Characteristics of Life

5. Reproduce

    • Produce new similar organism, more organisms like themselves.

Sexual – two parents; genetically different

Asexual – one parent; genetically the identical

      • Clones

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Characteristics of Life

6. Maintain a Stable Internal Environment

Homeostasis- keeping of an internal environment that is constant & stable.

      • Shivering & Sweating to maintain body temperature.
      • Eating when hungry to maintain energy levels.
      • Sleeping when tired to rest and repair the body.
      • Increase in breathing rate to main oxygen levels during physical exertion.

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Characteristics of Life

7. Obtain and Use Energy

Metabolism – All of the chemical reactions that the body uses to build up or break down material to carry on life processes.

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Characteristics of Life

8. Taken as a group (population), living things evolve

    • Change over time
      • Requires a population of organisms
      • Requires thousands, hundreds of thousands, or millions of years

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Check for Understanding

          • What molecule serves as the universal genetic code?

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2. What is the difference between growth and development?

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3. Compare sexual reproduction to asexual reproduction.

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4. What does the following mean; all living things evolve?

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So, is it living, nonliving, or dead?

  • Living (biotic)- Demonstrates ALL 8 characteristics of living things.
  • Nonliving (abiotic)- DOES NOT demonstrate ALL 8 of the characteristics of living things (may demonstrate some of them).
  • Dead- Demonstrated the 8 characteristics of living things at one time but DOES NOT CURRENTLY do so.

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