Characteristics of Life

1
Characteristics of Life
Listen to recordings (by clicking on the speaker
icon) or read notes under slide.
2
What is alive

• Organisms include bacteria, plants, animals,
  fungi, protists
• Does not include viruses.
• Viruses are not cells.
• Viruses are proteins and nucleic acids

Ebola virus Referred to as a hemorrhagic virus
because it causes hemorrhages in its victims.
3
All organisms are composed of cells

• Cells are the basic unit of structure and
  function of all living things
• Organisms are Unicellular Multicellular

4
Organization

• Living things are all highly organized.
• Organisms take substances from environment and
  organize them in complex ways.

Cross section of a root showing root hairs on the
outer surface.
5
Energy use

• Energy is used to maintain organization.
• Metabolism Sum of all chemistry/ energy in a
  living thing.

Think what does this bird use energy for?
Cardinal
6
Homeostasis

• Maintaining a steady internal environment.
• External environment is always changing.

Think what does your body do to maintain
homeostasis?
Baby Sea Lion
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Growth

• All living organisms grow.
• Growth occurs by cell division and cell
  enlargement

Bacteria dividing after growth stage.
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Reproduction

• All species of organisms are capable of
  reproducing.
• Reproduction is essential to the species but not
  the individual.
• Reproduction is the transfer of genetic material
  from generation to the next

Think What happens to a species if they do not
reproduce?
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Answer these questions in your summary

• List all the characteristics of living things.
• Entropy is the natural tendency towards disorder.
  What do living things do that counters entropy?
• What is the chemistry/ energy use of living
  things called?
• Why are viruses not alive?
• Name 2 ways organisms maintain homeostasis (other
  than those mentioned in this lecture).