Levels of
Organization in Living
ThingsHow living things are organized
Vocab Refresher
FunctionWhat
something is
used for
Something’s
job
Purpose, role
StructureThe way
something is
constructed or
made
The way the
parts of
something are
arranged
ALL organisms perform
the functions of lifeReproduce
Grow and develop
Obtain and use ENERGY
Response to their environment (stimuli) to maintain balance (homeostasis)
Adapt to their environment over time (as a species, not individual)
Unicellular Organisms
Some organisms are made of only one cell
The cell performs ALL of the functions necessary for life
Uni- = one or single
Examples: Bacteria, protists, yeast
Multicellular Organisms
Have various levels of organization within them
Individual cells may perform specific functions (different types of cells)
Cells work together for the good of the entire organism
Cells depend on one another
Levels of organization
Cells
Tissues
Organs
Organ systems
Organism
CELLSBasic unit of structure
and function in living things (CELL THEORY!)
Serve specific functions (different types for different jobs!)
Examples: blood cells (erythrocytes), nerve cells (neurons), bone cells (osteocytes)
TISSUES Made up of cells that
are similar in structure and function
The cells work together to perform a specific activity
Examples: blood, nervous, bone
4 basic types in humans:
connective (blood, fat, ligaments, cartilage, bones, tendons),
epithelial (skin),
muscle (smooth, skeletal, cardiac)
nerve
ORGANS
Made up of tissues that
work together to perform a
specific activity
Examples: heart, brain, skin
ORGAN SYSTEMS
Groups of organs working together to perform specific functions for the organism
Examples: circulatory, muscular, digestive
ORGANISMS
Entire living things carrying out all life’s functions
Multicellular organisms made up of organ systems
Examples: mushroom, sunflower, human, fish
Unicellular – only made up of a cell (Ex. Bacteria, protist)
Levels of Organization
Cells
Tissues
Organs
Organ Systems
Organisms
Basic
Unit
of
Life