Levels of Organization

cell-tissue-organ- organ system-organism smallest/first/least complex largest/last/most complex

_______ the basic units of structure and function of all living things

_______ a group of similar cells working together to perform a specific function

_______ A group of tissues that work together to perform a function or task

_______ _______ a group of organs that work together to perform a complex function

_______ a living thing

_______ work together to form tissues, organs, and organ systems.

_______ What is the shape of a cell usually related to? You may or may not wish to distinguish between cytosol and cytoplasm. The correct use of each term is shown here. Most high school textbooks, however, use the word “cytoplasm” to mean “cytosol.”

Different cells are specialized for different _______. The difference can be the _______ of the cell.

There are _______ basic types of tissue in the human body. Muscle—can _______ to make the body move _______ tissue—carries messages between the brain and other parts of the body _______ tissue—provides support for the body and connects the various parts Epithelial tissue—protects the structures _______ it (like skin)

Examples of organs are: the heart, _______, stomach, and _______. _______ usually perform a more complex task than a tissue. Examples of organ systems are: circulatory, nervous system, _______ system, respiratory system, and _______ system.

Can unicellular organisms have tissues, organs, or organ systems? ____________________________________________________________________

_______ Can an organ belong to more than one organ system? For example, the heart is part of the circulatory and respiratory systems.

LEVEL ONE: CELLS Within a _______ organism there is a division of _______.  Division of labor means that the work of keeping the organism alive is _______ among the different parts of the body. 

LEVEL ONE: CELLS Each part has a _______ job to do.  And as each part does its special job, it works in harmony with all the other parts. The arrangement of specialized parts within a living thing is sometimes referred to as levels of _______.  Cells, of course, are the _______ level of organization.

LEVEL TWO: TISSUES In any multicellular organism, cells rarely work alone.  Cells that are similar in _______ and function are usually joined together to form tissues.  _______ are the second level of organization.

LEVEL TWO: TISSUES Bone cells in your body _______ bone tissue, a strong _______ tissue that gives you _______ and support.  Blood cells in your body are part of blood tissue, a _______ tissue responsible for transporting food and _______ throughout the body.

LEVEL THREE: ORGANS Tissues are further organized in _______, the third level of organization in living things.  Organs are _______ of different tissues that work _______. 

LEVEL THREE: ORGANS Your heart, for example, is an organ made up of muscle tissue, _______ tissue, and nerve tissue.  You are probably familiar with the names of many of the body organs.  The brain, _______, kidneys, and skin are some examples.

LEVEL FOUR: ORGAN SYSTEMS Like cells and tissues, organs seldom work _______.  They "cooperate" with one another and form specific organ systems.  Organ _______ are the fourth level of organization in living things. 

LEVEL FOUR: ORGAN SYSTEMS An organ system is a group of organs working together to perform a specific function for the _______.

LEVEL FIVE : ORGANISMS _______ are an organism.  Dogs, trees, and sunflowers are also organisms.  Even a _______ bacterium is an organism.  An organism is an entire living thing that carries out all the _______ life functions.  The organism is the fifth level of organization.

LEVEL FIVE : ORGANISMS Cells, tissues, organs, organ systems, organisms--each level of organization _______ with every other level.  The smooth functioning of a complex organism is the result of all its various parts working together.