A. Unicellular Organisms--Single-celled Organisms that do

all a living thing would----They dominate life on earth in

terms of numbers

IV. The Diversity of Cellular Life

B. Multicellular organisms

• Multicellular organisms– Made up of many cells– Depend on communication and cooperation between

specialized cells

---_______________-cells throughout organism can develop in

different ways to perform different tasks

Cell specialization

• 1. Specialized animal cells– eg. Red blood cells equipped to carry

oxygen ;cells specialized to produce proteins produced in pancreas(have many ribosomes and rough ER);muscle cells have actin and myosin cytoskeleton elements for contraction

• 2. Specialized Plant cells• ______________________-are tiny openings on

underside of leaves and exchange gases• _____________________-regulate gaseous

exchanges in stomata,changing shape due to plant’s internal conditions

•  

stomata Guard cells

C. Levels of Organization

– 1. individual cells– 2. _____________________-group of similar cells w/

particular function– 3. ______________-group of tissues working

together– 4. ______________-group of organs working

together for particular function•  

tissueorgan Organ system

Muscle cell Smooth muscle tissue Stomach Digestive system

Section 7- 4

Levels of Organization

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