Unit 3 Cells Lesson 6 - Cell Theory What do living things have in common?
Explore and question spontaneous generation, an early belief on the properties of life. Observing Phenomena
In the 1600s, this was a recipe for creating mice:
Place a dirty shirt in an open container of wheat for 21 days and the wheat will transform into mice.
1) Discuss what you think of this recipe. People may have believed that it worked because they did not notice the mice that were living in and reproducing in the wheat containers and maybe hiding beneath the dirty shirts. Observing Phenomena Another belief of spontaneous generation was that fish formed from the mud of dry river beds.
2) What do you think about the recipe for making fish from the mud of a dried up river bed? Observing Phenomena
People believed that these recipes would work because they believed in “spontaneous generation.”
3) Why do you think it is called spontaneous generation? Because a living thing spontaneously came into existence from a mixture of nonliving things. What beliefs about natural phenomena did you have as a young child? For example, some young children might think that clouds are fluffy like cotton balls or the moon is made of cheese. As you have gotten older, how have these beliefs changed as you acquired more knowledge? 4) Discuss why they might have believed these and what has changed people's understanding of living things today.
Investigation 1: Categorizing Substances
In your notebook, write a list of what you think all living things have in common. Investigation 1: Categorizing Substances Using the list of criteria you just wrote, separate the items listed on this slide according to whether you think they are living or nonliving. Only use the criteria you wrote, even if you know something is living or nonliving. Investigation 1: Categorizing Substances Now that you have sorted those things, is there anything that you can revise about your list of what ALL living things have in common? A living thing needs to meet all of the criteria in order for it to be called living, so consider your list carefully.
Investigation 1: Categorizing Substances
Scientists determine if something is living or not living if they have ALL criteria All living things: • have the ability to grow and develop. • use energy to “power” their life processes. • respond to their environment. • maintain a stable internal environment. • have the ability to reproduce. • made of one or more cells
Body Tube Nosepiece Stage Clips Eyepiece Arm Stage Course Adjustment Fine Focus Base Introduction p103 Life! This tropical beach and jungle environment is filled with living things. Which ones can you see in the photo? The palm trees and vines that grow in the jungle are living plants, and fish that swim in the warm tropical waters are living animals. Even the rock-like underwater coral reef was formed over thousands or millions of years by tiny animals called corals. Corals still live on the outer surface of this reef, though you would have to get much closer to see them. While many of the living things in this environment can be seen with the unaided eye, even more are not visible. The soil and water contain billions of microscopic organisms that are too small to be seen without a microscope. You have learned that some animals and plants have body systems and tissues. But others, like sponges, do not have true tissues. Bacteria are tiny living things that don't have tissues or body systems, so what do all living things have in common? In this lesson, you will learn that all living things are made of cells and that cells come from other cells. You will learn that organisms can be organized according to whether they are made of one or many cells. You will consider how information gained from observing living things at a very small scale allowed scientists to learn about single-celled organisms. You will also learn that the structure and function of a living thing is determined by all of its cells working together.
Sec 1. Cells of Multicellular Organisms p104 Multicellular organisms, or organisms that are made up of many cells. “multi,” meaning many Examples of Multicellular orgamisms: All animals, plants, most fungi
Cells are very small, so you usually need a microscope to see that these organisms are made of cells. Sec 1. Cells of Multicellular Organisms p104
Cells of multicellular organisms are specialized. This means that each kind of cell has a particular shape to do a particular job rather than to do all jobs.
1. Cells of Multicellular Organisms p104 Each specialized cell of a multicellular organism needs other cells to function. The cells of multicellular organisms work together to survive: • share nutrients and materials with other cells • communicate with one another through different chemical signals. • send and receive instructions from other cells about what to do or make. • Cells in a multicellular organism will even sacrifice themselves if they are infected or in some way endangering the survival of the neighboring cells. • If a cell does die, another cell will often divide and make a copy of itself to fill the empty space in the tissue. • Cell division also allows the whole organism to grow and form new parts during development. Sec 2. Cells of Unicellular Organisms p105 Unicellular organisms, or organisms that are made of only one cell. uni, meaning one Examples: Bacteria, Archaea, some fungi and Protists They are so small that they usually cannot be seen without a microscope. A unicellular organism behaves differently than a cell in a multicellular organism. The one cell of a unicellular organism can survive entirely on its own If the cell of a unicellular organism divides, another organism is Paramecium Euglena made. - this is the that most unicellular organisms reproduce or have offspring. Also, if the cell of a unicellular organism dies, the whole organism is dead, unlike in a multicellular organism. Cells of unicellular organisms are generally not specialized. Amoeba The one cell of the organism will perform all of the functions that organism needs to do to survive. 1. In what main way is a unicellular organism different than a multicellular organism? How are they different in scale? Unicellular organisms are made of only one cell, so they generally exist on a smaller scale than multicellular organisms, which are made of more than one cell. 2. If you cannot see most cells with just your eyes, how can you see a unicellular organism? You could use a microscope to see a unicellular organism. 3. How is cell division different for a unicellular organism than it is for a cell in a multicellular organism? When a unicellular organism divides, a new organism is made. When a cell in a multicellular organism divides, it creates another cell within the same organism.
Unicellular / Multicellular Organisms Microscope Lab Paramecium Muscle Tissue Onion Epidermis (skin)
Euglena Tilia Root Magnolia Stem Elodea Leaf
Amoeba Allium Root C.S. Cross Section W.M. Whole Mount L.S. Long Mount
All Living Things are made of one or more cells.
Sec 3: The structure and function of a living The Cell thing is determined by it one cell or Theory ALL of its cells working together.
All cells come from existing cells
Sec 3 Cell Theory P106-107 Sec 4. Viruses
Target questions for your notes What are viruses? Compare/contrast virus and bacteria? Research viral examples that affect humans (not computers) Sec 4. Viruses
A virus is a nonliving particle that makes copies of itself inside living cells. Viruses are not made of cells