Download single cell. - Sonoma Valley High School

7-4 the diversity of cellular life
Unicellular organisms
 Unicellular organisms
perform all of life’s
essential functions within
a single cell.
 There are far more
unicellular life forms than
multicellular ones.
Yeast cell
Multicellular organisms
 Cell specialization:
 Cells develop in different
ways to perform different
tasks for the whole
organism.
 Cells communicate and
cooperate with each other
volvox
P/S: why do cells of a multicellular organism
need to communicate?
Copepod (1mm)
Specialized cells
 Red blood cells:
transport O2
 Pancreatic cells:
produce enzymes to
digest food.
 Guard cells open &
close the stomata to
exchange gases and
water in plants.
Islet cells:
pancreas
Levels of organization
 Within an organism are 4 levels of organization
 1. cell
 2. tissue
 3. organ
 4. organ system
WB: what level of organization is our brain?
Tissue
• A group of similar cells that perform a
particular function.
Animal tissues:
epithelial, nervous, muscle, & connective
Organs
 Made of groups of
different tissues to
perform a specific
function for the body
 ex: heart, lung,
stomach, liver
Heart
liver
PS: discuss the functions of the organs listed
here
lungs
Organ system
 A group of organs
working together to
perform a specific
function.
 Specialization and
interdependence is one
of the remarkable
attributes of living things.
WB: which organs are found in the
digestive system?
Summary
Onion tissue
 Today’s topic was………………
 A tissue is ………………………
 Cells specialize because…………
 Cells cooperate because……….