Chapter 5 Lesson 3 "How Protists Survive"

Materials:

• Picture of Horse/plant combination.
• Worksheet of pictures of vehicles.
• Resource File optional

Objective:

• Students will describe how protists digest food.
• Students will explain how protists maintain water balance.
• Students will discuss how protists react to their environments and reproduce.

Alaska Standards:

• SCI A-15 Students will use science to understand and describe the local environment.
• SCI B-1 Students will use the processes of science: classifying.

Anticipatory Set: To emphasize the difficulties in classifying protists show the students this picture: (this a combination horse and plant) Then read them this senerio:

Suppose you are a biologist and discover this organism deep in an Amazon rain forest. After watching the organism you see that it can freely move around but never eats or drinks. You find that it is capable of drawing water up through its feet and its skin and hair is full of chloroplasts that enable it to make its own food using sunlight. It spends most of its time moving from sunny spot on the forest to the next. However, it reproduces in much the same way as the American Quarterhorse. Discuss with students nearby how the organism should be classified.

Scientists have had this same problem with protists. They have had many problems classifying the group because of the different ways they obtain food, the way the appear, the way they reproduce and the way they move. Basically the kingdom Protista has become the dumping ground for scientists. If the organism is Eukaryotic (with organelles and a cellular nucleus) but is not an animal, plant, or fungus it is dumped into the kingdom protista.

Teacher Input: Protists are classified by the way they move. Compare and contrast this to the way transportation systems are classified. Have the students compare different types of vehicals and classify them. Use the worksheet with the pictures of vehicles.

Cars, buses, trucks, move with wheels/ jets, ultralights, cesnas, all fly/ speedboats, wave runners, barges, and ships all travel on water.

Teacher Modeling: Students will discuss how they digest their food. They should trace the path of food through their digestive system. Then while using the picture on Page 95 or the resource file, students will discuss the differences between their system and this single celled organisms tools for digestion. Students and teacher shall define the three terms; Gullet, Food vacuole, Anal pore.

Check for Understanding: Students will be introduced to osmosis. Remind the students about how water is able to move in and out of cells. These single celled organisms will not survive if they do not have the same concentrations of materials in thier cells as the environment surrounding the cells or the ability to pump materials one way or another. Define Osmosis and contractile Vacoles.

Guided Practice:

Toss a soft object, to one of the students. Explain how they sensed and reacted. These microscopic organisms also can sense and respond. Read and discuss the importance of the first paragraph on P 97. Then discuss protist reproduction. How is it similar and different than bacteria, plants, and animal.

Closure: Go through the question on Page 98 with the students.

Independent Practice: Take the quiz on-line.

Duration:

40-45 minutes + 5 for Independent Practice (Could be longer if taken for homework).