LEVELS OF CELLULAR ORGANIZATION

Essential QuestionHow are living things organized?

HOW LIVING THINGS ARE ORGANIZED!

• CELL• TISSUE• ORGAN• ORGAN SYSTEM• ORGANISM

CELL

• The smallest unit of life.

UNICELLULAR ORGANISM

• Made up of just one cell that performs all of the functions necessary for life.

• Do not have levels of organization.• Disadvantage

– Entire organism dies if the single cell dies• Advantages

– Need fewer resources– Some can live in harsh environments (hot springs)

Diatom

MULTICELLULAR ORGANISMS• Made up of more than one cell.• Cells are grouped into different levels of

organization.• Cells are specialized to perform specific functions.• Disadvantages

– Need more resources than do unicellular organisms– Specialized cells must depend on each other to perform all of the

functions that an organism needs.• Advantages

– Longer lifespan– Organisms are larger and more complex.

TISSUE

• A group of similar cells that perform a common function.

Connective Tissue

ANIMAL TISSUES

• Nervous tissue• Epithelial tissue• Connective tissue• Muscle tissue

NERVOUS TISSUE

• Functions as a messaging system within the body

EPITHELIAL TISSUE

• Is protective and forms boundaries, such as skin.

CONNECTIVE TISSUE• Holds parts of the body together and provides

support and nourishment to organs. • Ex. Bones and blood

MUSCLE TISSUE

• Helps produce movement.

INVOLUNTARY MUSCLE VS. VOLUNTARY MUSCLE

• Voluntary muscles-muscles that you can control– Ex. Skeletal muscles-arm, facial, and leg.

• Involuntary-muscles that you cannot control– Ex. Heart and stomach

PLANT TISSUES

• Transport or vascular• Protective or dermal• Ground

TRANSPORT TISSUE

• Moves water and nutrients through the plant.

PROTECTIVE TISSUE

• Protects the outside of the plant.

GROUND TISSUE

• Provides internal support and storage.• Absorbs light energy to make food in

photosynthesis.

ORGAN

• A structure made up of a collection of tissues that carries out a specialized function.

STOMACHHow do the tissues in the stomach help to break down food in digestion?• Nervous tissue-sends messages to the

stomach’s muscle tissue to tell it to contract.• Muscle tissue-contracts, food and stomach

acids are mixed together, and the food breaks down.

PLANT ORGANS

• Leaf-contains protective tissues working together

• Stem and Root-organs that function to transport and store water and nutrients in the plant.

ORGAN SYSTEM

• A group of organs that work together to perform body functions.

• Each organ system performs a specific job.

DIGESTIVE SYSTEM

• Esophagus• Stomach• Small Intestine• Large Intestine

CIRCULATORY SYSTEM

• Delivers nutrients to body cells and carries away wastes.

• Carries oxygen to cells; removes carbon dioxide

RESPIRATORY SYSTEM

• Takes in oxygen

Excretory System

• Removes waste products from the body

VASCULAR SYSTEM

• Transports water and nutrients.• Xylem-transports water from roots to cell• Phloem-transports nutrients made in the leaf

to all parts of the cell.

HEART

• The cardiac muscle tissue contracts, making the heart pump.

• The nerve tissue brings messages that tell the heart how fast to beat.

• The blood tissue is carried from the heart to other organs of the body.

BLOOD FLOWRED LINES-OXYGEN-RICH BLOOD-transports oxygen and nutrients to throughout the body-to the body cells.BLUE LINES-OXYGEN-POOR BLOOD-Carries carbon dioxide and other waste productsout of the body.

The Color of Blood Trivia

Human blood is red, ranging from bright red when oxygenated to dark red when not.

It owes its color to hemoglobin, a metalloprotein compound containing iron in the form of heme, to which oxygen binds.

There exists a popular misconception that deoxygenated blood is blue and that blood only becomes red when it comes into contact with oxygen.

Blood is never blue, but veins appear blue because light is diffused by skin.

Moreover, the blood inside is dark red and exhibits poor light reflection.

From a physiological perspective, veins and arteries appear similar when skin is removed and are seen directly.