Tardigrades: Living extremely

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Scanning electron micrograph of Tardigrada, or water bear. Image Credit: Rick Gillis and Roger J. Haro Department of Biology University of Wisconsin - La Crosse.

Provenance: Image Credit: Rick Gillis and Roger J. Haro Department of Biology University of Wisconsin - La Crosse.
Reuse: This item is offered under a Creative Commons Attribution-NonCommercial-ShareAlike license http://creativecommons.org/licenses/by-nc-sa/3.0/ You may reuse this item for non-commercial purposes as long as you provide attribution and offer any derivative works under a similar license.

In-Class Activity 1_Extremophiles

Julia Kahmann-Robinson PhD and Marjorie Chan PhD, University of Utah Department of Geology & Geophysics

Purpose

Become acquainted with the Tardigrade ("water bear") extremophile, its living conditions, and importance of its scientific study.

Preparation

Have Internet access in your classroom.

Resources

1. Tardigrade YouTube video: http://www.youtube.com/watch?v=6H0E77TdYnY&continue_action=r7OE3bLJMHT8fAwevwnX9Oh_0zzl6Ajt2P3129QN588gcYR6MkEN_obkOAtaq5MUvFV4Yiq09ljbJDp8wedzPE1U417RionrJuPdT2CAALc=
2. SERC definition of Extremophiles: http://serc.carleton.edu/microbelife/extreme/extremophiles.html

Engage

Watch the following You Tube Tardigrade video from the SciShow: http://www.youtube.com/watch?v=6H0E77TdYnY&continue_action=r7OE3bLJMHT8fAwevwnX9Oh_0zzl6Ajt2P3129QN588gcYR6MkEN_obkOAtaq5MUvFV4Yiq09ljbJDp8wedzPE1U417RionrJuPdT2CAALc=

As students watch the video, have them answer the following questions:

1. What is a Tardigrade?
2. What type of environments can Tardigrade live in?
3. What is its importance to science?

Explore

Have students briefly "explore" other extremophiles and answer a few questions about their characteristics and report back to the class.

Explain

As students discuss Tardigrade and the type of environment in which it can survive, share the following terms related to types of extremophiles. Ask students to classify Tardigrade in one of these groups:

• Acidophile- high pH
• Alkaliphile- low pH
• Anaerobe- no need for oxygen
• Endolith- lives inside rocks
• Halophile- requires salt
• Piezophile/Barophile- requires high pressures
• Thermophile- lives in 40°C or higher
• Xerophile- limited water supply
• Psychrophile- lives in 15°C or lower

Elaborate

Where could Tardigrade live on Mars?

1. Display a global Map of Mars so that all regions can be viewed (see image file: Extremophiles (PowerPoint 2007 (.pptx) 3.9MB Oct23 12) )
2. Where could Tardigrade potentially live on Mars?
3. Is studying Tardigrade, and other organisms like it useful to space research? Why or why not?

Also, possibly consider where they live on Earth for comparison.

Evaluate

Ask students what other Extremophiles classifications (see above) could be present on Mars and give a short presentation on a type of extremophile other than Tardigrade.