Name: _______________________________
Bacteria
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 cyanidecontaminated 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.
Brainstorming
*Name two ways bacteria are beneficial.
*Names two places bacteria can live where other living things can’t.
*What drugs can kill bacteria?
*What are some bacterial illnesses and why are they such threats to health?
Student Objectives
Understand the diversity of bacteria and how bacteria are beneficial.
Learn about extremophiles—bacteria that thrive in extreme environments.
Write a news story about different types of bacteria.
Procedures
1. An extremophile and examples of bacteria that fall into this category include:
• Heat-loving bacteria that live in volcanic vents on Earth’s surface and
beneath the ocean
• Bacteria that can live in the ice packs of the Arctic and Antarctic
• Those that can withstand toxic environments such as acid pools, sulphur
geysers, or in places with high salt concentrations
• Some that can live in solid rock
2. Why are extremophiles of such interest to scientists? Some of the reasons were
covered in the video. For example, bacteria that can thrive in cyanidecontaminated 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. You are going to become reporters covering the Extreme Olympics. You will be
divided into five teams, each of which will research and report on bacteria that
would offer the best “performance” in these categories:
• High Tempers (bacteria that can withstand high temperatures)
• Ice Blockers (bacteria that exist in very low temperatures)
• Toxic Troopers (those that can withstand toxins such as radiation, salt,
sulphur, or acid)
• Rock and Rollers (bacteria living in solid rock)
• 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 may be useful as you conduct your research:
• The Guardians Extremophiles
http://www.theguardians.com/Microbiology/gm_mbm04.htm
• Microbe Zoo
http://commtechlab.msu.edu/sites/dlc-me/zoo/
• Stalking the Mysterious Microbe
http://www.microbeworld.org/
5. After you have finished your reports, select correspondents to present the
information to the class. Everyone in the group will have to have some
sort of role in the presentation.
Assessment
You will be graded on the following three-point rubric to evaluate your work during
this lesson.
• 3 points: Group was engaged in class and produced a complete report,
including all of the requested information.
• 2 points: Group participated in class and produced an adequate report,
including most of the requested information.
• 1 point: Group participated minimally in class 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.