Download Levels of Organization Notes

Levels of Organization
Division of Labor &
The First Level
Within multi-cellular organisms there is division of labor.
Division of labor means that the work (labor) of keeping the
organism alive is divided (division) among the different parts
of the body.
Each part has a specific 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 organization. Cells are the
first level of organization.
Cells: LOTS of Different Kinds!
Here are two examples. Can you guess what kind?
Nerve Cells
Skin Cells
Second Level: Tissues
In any multi-cellular organism, cells rarely work alone. Cells that
are similar in structure and function are usually joined
together to form tissues.
There are four basic/major types of tissues in the human body:
Muscle tissue
Nerve tissue
Connective tissue
Epithelial tissue
(There are other kinds of tissues besides these.) Other kinds of
tissue include bone tissue (a strong solid tissue that gives you
shape and support) made of bone cells in your body form bone
tissue. Blood cells in your body are part of blood tissue, a liquid
tissue responsible for transporting food and oxygen throughout
the body.
Let’s Look Again…
Here are the cells we saw before, but if you look closely, you can
see that they all look similar. Nerve cells working together make
nerve tissue, and skin cells make up a special type of epithelial
tissue.
Level Three: Organs
When a bunch of different types of tissues work together,
they form an organ. There are many organs in the body.
How many can you name??
Level Four: Organ Systems
A group of organs that work
together to perform a major
function is an organ system.
For example, your heart is
part of your circulatory
system, which carries oxygen
and other materials
throughout your body.
Besides the heart, blood
vessels are organs that work
in your circulatory system.
The nervous system detects and
interprets information from the
environment outside the body and
from within the body; controls
most body functions.
The immune system fights
disease.
The excretory system removes
wastes.
The endocrine system
controls many body processes
by means of chemicals, like
hormones.
The muscular system enables the
body to move; moves food
through the digestive system, and
keeps the heart beating.
The skeletal system supports and
protects the body, and works with
the muscular system to allow
movement; makes and stores
blood cells and stores some other
materials.
The digestive system takes food
into the body, breaks the food
down into smaller particles, and
absorbs the digested materials.
The respiratory system takes
oxygen into the body and
eliminates carbon dioxide.
The reproductive system
produces sex cells that can
unite with other sex cells to
create offspring; controls male
and female characteristics.
Level 5 - Organism
• When all the systems work together to make
a living thing (an organism).
• Organisms can be one cell big (amoeba,
bacteria) or more (human, ant, frog)
• In a multicellular organism, each cell must
carry out all the basic life functions and do
their specific job to keep the organism alive.
Let’s Review….
• 1st Level: Cells working together form
• 2nd Level: Tissues, which can form
• 3rd Level: Organs, which work together to
form
• 4th Level: Organ Systems, which work
together to form
• 5th Level: Organisms!