Levels of Organization

Unicellular Organisms Unicellular organisms are made of only one cell. They can be: Prokaryotes- do not have a membrane-bound nucleus Eukaryotes- have a nucleus surrounded by a membrane and other specialized organelles.

Multicellular Organisms CELLS Each type of cell in a multicellular organism has a specific job that is important to the survival of the organism Cells become different types during cell differentiation Stem cells- unspecialized cells that can develop into many different cell types Stem cells can produce new muscle cells when fibers are torn In plants, these unspecialized cells are called meristems.

Tissues Tissues -groups of similar cells that work together to carry out a specific task Animals have 4 main types of tissue: muscle epithelial nervous connective-(ex: blood, bone, cartilage)

Plants have 3 main types of tissue: dermal vascular ground

Organs Organs -groups of different types of tissues working together to perform a particular job A leaf is a plant organ that specializes in photosynthesis.

Organ Systems Organs Systems-groups of different organs that work together to complete a series of tasks. Ex: Digestive system includes the stomach and intestines Plants have 2 major organ systems: shoot system root system Multicellular organisms usually have may organ systems Each organ system depends on the others and cannot work alone

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Cells Tissues Organs Organ System Organism