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Explore the characteristics of single and multicellular organisms and their ability to survive on their own. Learn about the functions of cells and how they work together in multicellular organisms. Discuss the double life of cells and how to distinguish between single-celled and multicellular organisms.
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Day 13 Domain Eukarya Domain Archaea Domain Bacteria Living Things We've been learning about organisms in different domains and kingdoms. Are all of those organisms living? Yes. The definition of an organism is "a living thing that can survive on its own." All organisms are living. 1
Single vs. Multicellular Contrasting Case Activity 3 Investigation 3 – Microscopic Life
Organisms and Living Things All organisms are living things. Are all living things organisms?
Microscopic Images What do these two images have in common? How are they different? Are they both living?
Life of a Cell • Inside every cell, a number of important functions must occur. • The cell must allow nutrients and gases in and out, and it must eliminate waste. • Cells reproduce by splitting into new cells. Where else have we seen these processes occur?
The Basic Unit of Life • The cell is called the basic unit of lifebecause it is the smallest unit capable of carrying out the functions of life. • Some cells are part of a multicellular organism. • This kind of cell has two jobs: to carry out all the functions needed to keep itself alive, and to work with surrounding cells to help keep the organism alive.
Cells Working Together • Can all cells survive on their own? • Could the cells pictured here survive without the rest of the organism?
Compare Single Cells What do these two cells have in common? How are they different?
Compare Single Cells • Like a cheek cell, a paramecium is a single cell that carries out all the functions of life. • Unlike a cheek cell, a paramecium can survive independent of the cells around it. • This special quality makes a paramecium an organism as well as a cell. Does living independently mean a paramecium does not need anything from its environment?
Discussion • A 19th-century biologist studying cells described them as leading a “double life.” What did he mean by this? • What clues might you look for to determine whether a cell is a single-celled organism or part of a multicellular organism?