What do you call somebody with more than one cell phone? A multicellular organism.

Plants, animals, and other living things are all made up of cells! 

Cells are the basic unit of life that carry out different functions for growing, reproducing, and getting rid of waste. Some organisms are made up of a single cell, like bacteria, while others are made up of trillions of cells like humans. In unicellular and multicellular organisms cells function differently, but every organism has specialized cell structures that are called organelles. When comparing, students should be able to identify differences and similarities between multicellular and unicellular organisms. 

Ask students to give examples of multicellular and unicellular organisms to ensure that students can identify each type of organism on a macro level.
  

Our body can do a lot! We eat, exercise, breathe and remove waste. Each organism uses different processes to carry out life functions. Carefully study all the processes used by both organisms. Have students compare how functions (for nutrition, transport, respiration, excretion, regulation, and locomotion) are carried out in multicellular and unicellular organisms. 

Multicellular organisms 

Just like a pyramid made up of small bricks, our bodies consist of cells. 

All cells work together to complete bodily functions, like a well-oiled machine. The body is made up of many interacting systems in multicellular organisms. The systems in the human body are groups of cells that work together. These cells form tissues and organs that are specialized for particular body functions. Different organs work together to make up organ systems that help organisms function. The nervous system, digestive system, muscular system, respiratory system, and circulatory system are all examples of systems in the body. 

Ask students to describe how one of these systems functions and the parts that are involved. Each cell type helps carry out a function, for example, the muscle cells aid in movement, Intestinal cells play a part in digestion. These organisms need all parts of themselves to survive. Ask the following questions What are other functions being carried out in the organism? What functions do the other cell types assist with? 

Unicellular organisms  

Single-celled organisms have one cell that can perform all the functions required by the organism, while multicellular organisms use many different cells to perform their functions. 

An example is an amoeba (pictured above). An amoeba is a slipper shaped single celled organism that lives in damp environments. Nutrients are absorbed through the mouth pores. Food and waste are transported in vacuoles, and waste is removed through the anal pore. The micronucleus in unicellular organisms stores DNA material, and Flagella or Cilia aid in locomotion. 

End of lesson:  

- Primary Keyword - unicellular, multicellular, types of organisms 

- Secondary Keyword - cell, organism, functions