Download Life Science: Bacteria

Life Science: Bacteria
Teacher’s Guide
Grade Level: 6-8
Curriculum Focus: Life Science
Lesson Duration: 2–3 class periods
Program Description
Bacteria are everywhere. And it’s a good thing, too. These one-celled microbes supply the biosphere
with nitrogen and carbon. They help digest food. They can even clean up a cyanide-contaminated river.
The most diverse life on the planet, bacteria thrive in environments inhospitable to other life, such as
sulphurous geysers or deep in solid ice. Bacteria also cause devastating human illness. The plague that
killed one-third of Europe’s population in the 14th century was bacteria borne. Despite the killer bugs,
the vast majority of bacteria are beneficial—even necessary. They really are mighty microbes.
Discussion Questions
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What are bacteria and to what branch of the tree of life to they belong?
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Name several ways bacteria are beneficial.
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Names some places bacteria can live where other living things can’t.
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What drugs can kill bacteria?
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What are some bacterial illnesses and why are they such threats to health?
Lesson Plan
Student Objectives
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Understand the diversity of bacteria and how bacteria are beneficial.
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Learn about extremophiles—bacteria that thrive in extreme environments.
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Write a news story about different types of bacteria.
Materials
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Computer with Internet access
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Print resources about extremophiles.
Life Science: Bacteria
Teacher’s Guide
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Procedures
1. Ask the class to define an extremophile and give examples of bacteria that fall into this category.
Some include:
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Heat-loving bacteria that live in volcanic vents on Earth’s surface and beneath the ocean
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Bacteria that can live in the ice packs of the Arctic and Antarctic
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Those that can withstand toxic environments such as acid pools, sulphur geysers, or in
places with high salt concentrations
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Some that can live in solid rock
2. Discuss why extremophiles are of such interest to scientists. Some of the reasons were covered
in the video. For example, bacteria that can thrive in cyanide-contaminated water are valuable
in cleaning up the toxin. Heat-loving bacteria found in Yellowstone’s hot springs can safely
bleach paper. Other bacteria are beneficial in cleaning up oil spills. Learning about how bacteria
can live in such hostile environments gives scientists clues about how life might exist on other
planets that aren’t as seemingly life-friendly as Earth.
3. Explain that students are going to become reporters covering the Extreme Olympics. Divide the
class into five teams, each of which will research and report on bacteria that would offer the
best “performance” in these categories:
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High Tempers (bacteria that can withstand high temperatures)
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Ice Blockers (bacteria that exist in very low temperatures)
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Toxic Troopers (those that can withstand toxins such as radiation, salt, sulphur, or acid)
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Rock and Rollers (bacteria living in solid rock)
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Golden Oldies (bacteria that can survive for very long periods of time)
Each report should contain an overview of the type of extremophile, what is known about
how the microbes live, possible benefits of the bacteria, and “contenders” in the
competition. Reports should conclude with the “winner” for the group: the most extreme
extremophile in the category.
4. The following Web sites will be useful to students as they conduct their research:
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The Guardians Extremophiles
http://www.theguardians.com/Microbiology/gm_mbm04.htm
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Microbe Zoo
http://commtechlab.msu.edu/sites/dlc-me/zoo/
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NASA’s Other Extreme Earth Life
http://www.resa.net/nasa/otherextreme.htm
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Stalking the Mysterious Microbe
http://www.microbe.org/
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Thursday’s Classroom: Life on the Edge
Published by Discovery Education. © 2005. All rights reserved.
Life Science: Bacteria
Teacher’s Guide
http://www.thursdaysclassroom.com/index_09sep99.html
5. After the groups have finished their reports, have each select a correspondent to present the
information to the class in a mock broadcast from the Extreme Olympics.
Assessment
Use the following three-point rubric to evaluate students' work during this lesson.
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3 points: Students were highly engaged in class discussions and produced a complete
report, including all of the requested information.
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2 points: Students participated in class discussions and produced an adequate report,
including most of the requested information.
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1 point: Students participated minimally in class discussions and created an incomplete
report with little or none of the requested information.
Vocabulary
antibiotic
Definition: Any substance that kills bacteria
Context: Penicillin was the first antibiotic discovered to treat bacterial infections.
bacteria
Definition: Single-celled prokaryote organisms that reproduce by simple cell division
Context: Bacteria are the most diverse and numerous living things on Earth.
eukaryote
Definition: Type of life in which organisms have cells that contain a distinct nucleus
Context: Plants and animals belong to the eukaryote branch of life.
extremophile
Definition: An organism that thrives in very inhospitable environments where other life can’t
survive
Context: Many extremophiles are bacteria that can withstand temperature extremes, high
pressure, or toxins.
microbe
Definition: Short for “micro-organism,” a microscopic organism
Context: Bacteria are types of microbes.
prokaryote
Definition: Type of life to which bacteria belong characterized by cells with no nucleus
Context: Bacteria belong to the prokaryote branch of life.
Academic Standards
National Academy of Sciences
Published by Discovery Education. © 2005. All rights reserved.
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Life Science: Bacteria
Teacher’s Guide
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The National Science Education Standards provide guidelines for teaching science as well as a
coherent vision of what it means to be scientifically literate for students in grades K–12. To view the
standards, visit this Web site:
http://books.nap.edu/html/nses/html/overview.html#content
This lesson plan addresses the following national standards:
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Life Science: Structure and function in living systems; Regulation and behavior; Diversity
and adaptations of organisms
Mid-continent Research for Education and Learning (McREL)
McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K–12 Education
addresses 14 content areas. To view the standards and benchmarks, visit
http://www.mcrel.org/compendium/browse.asp
This lesson plan addresses the following national standards:
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Science: Life Sciences—Understands the structure and function of cells and organisms;
Understands relationships among organisms and their physical environment; Understands
biological evolution and the diversity of life
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Language Arts—Viewing: Uses viewing skills and strategies to understand and interpret
visual media; Writing: Uses the general skills and strategies of the writing process, Gathers
and uses information for research purposes; Reading: Uses reading skills and strategies to
understand and interpret a variety of informational texts
Support Materials
Develop custom worksheets, educational puzzles, online quizzes, and more with the free teaching tools
offered on the Discoveryschool.com Web site. Create and print support materials, or save them to a
Custom Classroom account for future use. To learn more, visit
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http://school.discovery.com/teachingtools/teachingtools.html
Also find more Discovery lesson plans devoted to bacteria at:
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Curriculum Center: Bacteria
http://school.discovery.com/curriculumcenter/bacteria/
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Understanding: Bacteria
http://discoveryschools.com.au/guides/bacteria/overview.html
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Introduction to Bacteria
http://school.discovery.com/lessonplans/programs/bacteria/index.html
Published by Discovery Education. © 2005. All rights reserved.