Did we explain well enough what "levels of organization" means? Think about your school, as an example. Its levels of organization can include:

• Buildings (classrooms, library, offices, gym, lunchroom, etc.)

• Administration (school board, superintendent, principal)

• Activities (teaching, learning, sports, club meetings, etc.)

The Living and the Dead

Ever wonder what makes the difference between being dead and alive? To be alive you have to be well organized - or at least your cells do.  Consider the pictures of water or the rocks ... dead, right? Water only has one kind of molecule in it, and these molecules are randomly moving around - not very well organized.  Rocks may have several kinds of molecules that are locked into position by simple interactions with each other. However, these molecules don't really DO anything.

Survival

• Non-living things don't have to do anything.

• Cells have to DO many functions in order to stay alive.

• To DO so can require correct operations at many levels of organization

Normal function of cells depends on normal function of the many structures inside cells that help cells survive. These structures are called "organelles" ("little organs").  When our cells are healthy, we are healthy. When our cells are sick, we are sick. Sick cells reflect disease.

Diagram of a cell, which has many parts called organelles

Organelles that are damaged or diseased cannot perform their roles properly.

• Cells do not work as well as they get older.
• Cells are damaged by disease and "wear and tear" of living.
• Many cells die, even without disease (example: "shedding" of skin).
• Big problems can result when cells do not replace themselves as they die (example: skin gets thinner and more easily damaged in old age; death of neurons can cause senility, Parkinson's disease, paralysis).
• Big problems result if cells replace themselves in an out-of-control way (example: cancer).
  

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