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Odyssey of Life, Part II -- The Unknown World

Classroom Activity

Objective
To investigate some of the organisms living in the microbial world.

• copy of "Did You See That?" student handout (PDF or HTML)

1. Microorganisms are everywhere. To help students see where these organisms live and why they live there, have them conduct this activity.

2. If you don't have access to a worm bin or compost pile, see the Making a Worm Bin teacher instructions sheet, to have students set up their own bin. Once you have a sample from a bin, copy and distribute the "Did You See That?" student handout.

3. Set up separate samples of worm bin material, pond water, aquarium water, yeast (in water), and grass cuttings (in water—place dry grass in water and leave it in the sun for a week before you study the sample). Add samples of your own choosing if you like, and have students do Part I and look at each sample through a microscope that is at least 100x.

4. Once students have identified the organisms they observed, have them generate ideas in Part II about what enables the organisms to live in the environments in the samples. Then have each student choose an organism for further study, including how it respires, moves, reproduces, and defends itself. Finish with a whole-class discussion about each of the organisms studied and their functions.

The following are just some of the microorganisms and organisms that might be found in the samples.

• worm bin sample—molds, fungi, bacteria, tiny white insects called springtails, and small arthropods such as beetle mites

• pond water—insect larvae, amoebae, paramecia, euglenas, fungi, algae, volvoxes, and copepods

• aquarium water—algae, tiny limpids, protozoa, and insect larvae

• yeast—yeast

• grass cuttings—paramecia and nematodes

Book

Lewin, Roger. The Origin of Modern Humans. New York: Scientific American Library: Distributed by W.H. Freeman, 1993.
Looks at possible preludes to Homo sapiens, various hypotheses regarding the origin of modern humans, the idea of a Mitrochondrial Eve, the archeology of modern humans and the origin of language.

Web Sites

NOVA Online—Odyssey of Life
http://www.pbs.org/nova/odyssey/
Includes a cyberdebate about how humans evolved; time-lapse sequences of growing human, pig, chicken and fish embryos; an interview with photographer Lennart Nilsson; an essay about the commonalities among species; and an online activity that reveals what bugs live in, on and around us.

Talk Origins
http://www.talkorigins.org/
This newsgroup is devoted to the discussion and debate of biological and physical origins. Most discussions in the newsgroup center on the creation-evolution controversy, but other topics of discussion include the origin of life, geology, biology, cosmology and theology.

The Visible Embryo
http://www.visembryo.com/
Follows human embryological development over 40 weeks, providing in-depth information about what occurs at each stage. Requires Shockwave or QuickTime plug-ins.

The "Did You See That?" activity activity aligns with the following National Science Education Standards:

Grades 5-8

	Science Standard C: Life Science

Structure and function in living systems

• Specialized cells perform specialized functions in multicellular organisms. Groups of specialized cells cooperate to form a tissue, such as a muscle. Different tissues are, in turn, grouped together to form larger functional units, called organs. Each type of cell, tissue and organ has a distinct structure and set of functions that serve the organism as a whole.

Grades 9-12

	Science Standard C: Life Science

The cell

• Cells can differentiate, and complex multicellular organisms are formed as a highly organized arrangement of differentiated cells. In the development of these multicellular organisms, the progeny from a single cell form an embryo in which the cells multiply and differentiate to form the many specialized cells, tissues and organs that comprise the final organism. The differentiation is regulated through the expression of different genes.

Biological evolution

• The great diversity of organisms is the result of more than 3.5 billion years of evolution that has filled every available niche with life forms.

• The millions of different species of plants, animals and microorganisms that live on Earth today are related by descent from common ancestors.