Protists: Pond Microlife

Science, Grade 6

Protists: Pond Microlife

Multimedia Lesson

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Table Of Contents: Protists: Pond Microlife

1. What Is a Protist?

2.1. Kingdom Protista
The Kingdom Protista is the most diverse group of organisms. Some protists are unicellular (single-cell), while others are multicellular (multi-cell).
2.2. Protist Categories
The wide variety of characteristics of the numerous protist species makes it difficult to categorize them, but scientists have developed a method that places each species into three separate categories: animal-like, plant-like (algae) and fungus-like.

2. Plant-Like Protists

3.1. Algae
Plant-like protists are known as algae, typically found in freshwater habitats. Algae can be unicellular or multi-cellular.
3.2. Algae Contain Chlorophyll
All algae contain the green pigment chlorophyll in their chloroplasts which gives them the ability to make their own food by photosynthesis.
3.3. Examples of Plant-Like Protists
Examples of plant-like protists include euglenas, volvox, and spirogyra among others.

3. Euglena

4.1. Euglena Characteristics
A euglena is a one-celled alga with both plant and animal characteristics.
4.2. Euglenas Have Chlorophyll
It has chloroplasts that contain chlorophyll and makes its own food when sunlight is available.
4.3. Euglena Eyespot
Its eyespot responds to light which helps the euglena find areas with sunlight needed for photosynthesis.
4.4. Euglena Nutrition
In the absence of light, a euglena acts like an animal and captures nutrients from the environment.
4.5. Euglena Movement
A euglena moves by whipping its flagellum around like a little motor. A star-like structure called the contractile vacuole helps to remove excess water.

4. Volvox

5.1. Volvox Characteristics
Volvox is a freshwater, chlorophyll-containing green alga that occurs in ball-shaped colonies.
5.2. Volvox Colony
Each colony is composed of 500 or more individual cells.
5.3. Volvox Habitat
Volvox is found in ponds, creeks and even in shallow puddles. It spins clockwise through the water using its flagellum.
5.4. Volvox Reproduction
Volvox reproduces by forming daughter colonies. When the daughter colonies mature, the parent colony ruptures and releases them.

5. Spirogyra

6.1. Spirogyra Characteristics
Spirogyra appears as green filaments commonly found free-floating in freshwater habitats.
6.2. Spirogyra Filaments
Its filaments are composed of cylinder-shaped cells containing spiral green chloroplasts.
6.3. Spirogyra Reproduction
Spirogyra reproduces by both sexual and asexual reproduction.

6. Pause and Interact

7.1. Review
Use the whiteboard tools to complete the activity.
7.2. Euglena
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.
7.3. Volvox
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.
7.4. Spirogyra
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.

7. Animal-Like Protists

8.1. Protozoa
Protists classified as animal-like are called protozoa and share some common traits with animals.
8.2. Characteristics of Animal-Like Protists
All animal-like protists are heterotrophs and are able to move in their environment to find food. Unlike animals, however, animal-like protists are all unicellular (single-celled).

8. Amoeba

9.1. Amoeba Habitat
The amoeba is a tiny, one-celled protozoan found in fresh and saltwater habitats.
9.2. Amoeba Movement
It moves by continually changing its body shape by stretching its cytoplasm into fingerlike projections called pseudopods (false feet).
9.3. Amoeba Nutrition
The pseudopods also are used to surround and capture tiny food particles —mainly bacteria, algae, and other microscopic protozoa—from the surrounding water.
9.4. Amoeba Food Vacuole and Lysosomes
The captured food particle forms a bubble-like food vacuole which is digested by the cell’s lysosomes.
9.5. Amoeba Nucleus and Contractile Vacuole
The disk-shaped nucleus controls the growth and reproduction of the amoeba. The contractile vacuole pumps excess water out of the cell.
9.6. Amoeba Reproduction
The amoeba reproduces asexually by a process called binary fission (splitting in two). The cytoplasm pinches in half to form two identical organisms (daughter cells).

9. Paramecium

10.1. Paramecium Characteristics
The paramecium is one of the most complex protozoa found in many freshwater environments.
10.2. Paramecium Movement
It moves by using hair-like cilia that extend from the cell membrane.
10.3. Paramecium Nuclei
A paramecium has two nuclei – a macronucleus which controls the basic cell functions and a micronucleus which functions in reproduction.
10.4. Paramecium Nutrition
Paramecia feed on bacteria that are swept into the oral groove by the cilia and form food vacuoles. Excess water is pumped out of the cell by the contractile vacuole.
10.5. Paramecium Reproduction
Paramecium splits in half to reproduce two new paramecia by a process called binary fission.

10. Pause and Interact

11.1. Review
Use the whiteboard tools to complete the activity.
11.2. Amoeba
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.
11.3. Paramecium
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.

11. Fungus-Like Protists

12.1. Characteristics of Fungus-Like Protists
Fungus-like protists share characteristics of both protists and fungi.
12.2. Fungus-Like Protist Feeding and Reproduction
They feed on decomposing organic materials and reproduce by spores. All fungus-like protists are able to move at some point in their lives using pseudopods.
12.3. Types of Fungus-Like Protists
There are three main types of fungus-like protists: water molds, downy mildews, and slime molds.

12. Slime Mold

13.1. Slime Mold
Slime molds come in a variety of forms and colors ranging from yellow, to blue, violet and jet black.
13.2. Slime Mold Reproduction and Feeding
They are similar to fungi in that they reproduce by spores and feed on decaying plants and animals.
13.3. Slime Mold Movement and Habitat
At some point in their life cycle, slime molds move by means of pseudopods. They are typically found in damp and shady areas.

13. Pause and Interact

14.1. Review
Use the whiteboard tools to complete the activity: Describe the main characteristics of the three groups of protists.

14. Vocabulary Review

15.1. Vocabulary Matching Review
The paramecium is one of the most complex protozoa found in many freshwater environments.

15. Virtual Investigation

16.1. Comparing Algae & Protozoa
Although algae and protozoa are placed within the same kingdom, there are a number of differences that make these organisms unique. In this virtual lab investigation, you will observe and identify the similarities and differences of these diverse organisms in the Kingdom Protista.

16. Assessment

17.1. Protists