ORGANIZATION Cells are the basic unit of life: Living things are made of cells Life functions happen in cells

Cells work together to make- TISSUES Tissues are a group of cells doing a similar function, such as muscle tissue

Similar tissues work together - -to make ORGANS Organs are similar tissues working together to accomplish a life function.

Organs are grouped together in -organ SYSTEMS Systems work together to perform life functions

COMPLEX ORGANISMS -are made of many organ systems These organ systems each perform specific functions and together, they maintain homeostasis.

Not all organisms Have all these levels of organization. Some organisms are unicellular, so they will not have tissues or organs, only organelles.

Simpler organisms Will only have tissues, such as this planaria.

Homeostasis Is easier to maintain if you are multicellular, as long as you have this “division of labor”

Mitosis Creates this organization because cells produce exact copies of themselves: If it is a liver cell, it will produce another liver cell.

The DNA -In each cell of a multicellular organism is an exact copy of the first, original cell of that organism, but as the organism developed, cells differentiated, or took on a specific structure for a specific job.

DNA carries the instructions -for each cell, but parts of the DNA are “turned on”, or active, and parts are”turned off” Remember, the fragment of a chromosome that carries instructions for a specific protein is the GENE

From smallest to largest- DNA  Gene  Chromosome  Cell  Tissue  Organ  Organ System  Organism  Population  Community  Ecosystem  Biome  Biosphere!!