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Jewel of the Earth

Classroom Activity

Learning Objective | Materials | Background | Procedure | Activity Answer | Links & Books | Standards  Print this Teacher's Guide (PDF, 7 pages)

Activity Summary
Students set sticky traps to collect organisms, identify and classify the organisms they find, and determine when the organisms first evolved.

Learning Objectives
Students will be able to:

• collect and analyze organisms.

• use a dichotomous key to identify organisms.

• classify organisms according to order.

• trace organisms back to when they first evolved.

• copy of the "Organism Hunt" student handouts (PDF or HTML)
• copy of the "Links and Books" student handout (PDF or HTML)
• sticky traps or cardboard wrapped with packing tape (sticky side up)
• white paper
• magnifying glass
• access to Internet for identification keys

Background
Every school and home contains organisms. Many are too tiny to see with the naked eye but others are visible upon close inspection. Some of these inhabitants include insects, spiders, and other tiny animals. They have existed from prehistoric times and some of them have not changed much in millions of years. This activity will allow students to find and study some of these organisms.

Organisms will most likely be found in damp places like a basement, a locker room, or a teacher's lunchroom. Students will place sticky traps (often used for mice) to trap organisms over a 48-hour period. You may need to scout good locations by asking the custodian for helpful hints. If you are in a building that has mice or other small rodents, you will be less likely to trap them if you use cardboard wrapped with double-stick tape or packing tape (sticky side up).

Most of the organisms students find will be arthropods, such as insects, millipedes, centipedes, and spiders. Arthropods account for more than 75 percent of all known species and are part of the largest and most diverse animal phylum on Earth, Arthropoda. This phylum includes classes for insects, millipedes, centipedes, spiders, crabs, lobsters, shrimp, and others.

A dichotomous key can be used to identify the arthropods. These are available online or in print (several online keys are listed in a student handout). The key prompts the user to answer a question yes or no and then moves him or her on to another question until the organism is identified. The questions relate to the presence, absence, or number of various body parts on the organism and to adaptations.

If students do not collect any arthropods, describe five classes under the phylum Arthropoda and have student teams choose an organism in each class for further research. Have teams find images of each organism in their class on an arthropod Web site. Then ask students to make a chart that describes the organism's class and includes information about the time period the organism dates to, the organism's habitat, and adaptive features and body parts that allow each organism to live in particular habitats.

Arthropod Classes

• Diplopoda or millipedes (30 or more pairs of jointed legs)
• Chilopoda or centipedes (15 or more pairs of jointed legs)
• Arachnida or spiders and their relatives (4 pairs of walking legs)
• Insecta or insects (3 pairs of jointed legs)
• Crustacia, which includes lobsters, shrimp, and crabs (5 pair of walking legs)

1. List on the board the types of insects students have seen. Ask students if everything on the list is an insect. (Chances are students will have mentioned spiders, and maybe even centipedes or millipedes, which are not insects.) Clarify for students that insects are only one of a number of classes within the phylum Arthropoda, which also includes spiders, millipedes, and centipedes, as well as crabs and lobsters. All arthropods have an exoskeleton, paired and jointed appendages, and segmented bodies. Insects are characterized by a hard external skeleton, three body sections, six legs, a single pair of antennae, wings, and compound eyes.

2. Ask students where they found the organisms they listed. Why might they be found there?

3. Organize students into teams and distribute the student handouts and other materials to each team (sticky traps or sheets of sticky tape are available at hardware stores).

4. Review instructions on the student handout with the class before conducting the activity. Have students decide where they want to place the traps and then place them there. If traps are placed outside of the classroom, add a note with the trap explaining to others who may see it why it is there.

5. After 48 hours, check the trap locations yourself before students gather them to see what has been collected (if a mouse becomes trapped, remove the trap and properly dispose of the mouse). If particular traps have not collected enough organisms, either brainstorm with students new places to situate the traps or restructure teams to work with the traps that do have organisms.

6. Once all the traps have been collected, have each team catalog, research, and identify the organisms on its trap according to the instructions on the student handout. Review how to use a dichotomous key for those students who may not have used one before. Once identifications have been made, ask for student volunteers to describe the organisms they found. Make a list on the board of each organism discovered.

7. After all teams have presented their reports, have each team choose one of the organisms on the board for further study. Make sure that the organism is part of the phylum Arthropoda. Ask each team to create a tree that includes all the major orders within the phylum and to categorize its chosen organisms into the correct order (class if possible) within the phylum.

8. Have teams conduct research to determine the evolutionary history of their organisms. Teams should then create a time line showing the eons, eras, and periods of geologic time and note on the time line the approximate time period when their organism evolved. How long has their organism been on Earth? What are the similarities and differences between today's organism and its ancestor?

9. As an extension, have students create correctly sized papier-mâché models or drawings of one of the prehistoric counterparts to their organism. Ask students to label each of the organism's parts.

Students will usually trap more organisms near plants and carpeting or windows. In traps used to test the activity, the following arthropods were found:

• ants
• book or dust lice
• boxelder bugs
• clothes moths
• crickets
• fruit flies
• houseflies
• Japanese beetles
• midges
• plaster beetles
• spiders (assorted)
• thrips
• white flies

When testing this activity, the following organisms were collected:

Web Sites

NOVA—Jewel of the Earth
www.pbs.org/nova/jewel
Find out what is so compelling about insects in amber, follow a bee's journey from when it first became trapped in amber millions of years ago until now, see photos of amber inclusions, and learn where amber can be found worldwide.

Amber: Window to the Past
www.amnh.org/exhibitions/amber/index.html
Explains how amber preserves organisms and describes different kinds of amber.

Jurassic Park—Fact or Fiction?
www.nhm.ac.uk/science/features/amber.html
Considers the question of whether it is possible to extract dinosaur DNA from insects and recreate these creatures from ancient history.

Welcome to the World of Amber
www.emporia.edu/earthsci/amber/amber.htm
Provides information about amber, including its physical properties, uses, and geologic and geographic occurrences.

Books

Amber: The Natural Time Capsule
by Andrew Ross. Harvard University Press, 1998.
Describes the properties of amber and includes sections on insect identification.

Amber: Window to the Past
by David A. Grimaldi. Harry N. Abrams, 2003.
Discusses the properties of various types of amber, its most common localities, and the types of life it typically preserves. Includes numerous photographs.

Life in Amber
by George O. Poinar. Stanford University Press, 1992.
Surveys life-forms that have been found in amber and includes numerous photographs of them.

The "Organism Hunt" activity aligns with the following National Science Education Standards (see books.nap.edu/html/nses).

Grades 5-8
Science Standard C
Life Science
Diversity and adaptations of organisms

Grades 9-12
Science Standard C
Life Science
Biological evolution

Classroom Activity Author

A teacher for 25 years, Shannon C'de Baca teaches and serves as a consultant for national and state agencies working to improve science teaching. Her teaching practices have been recognized with national awards from the Milken Family Foundation and the National Science Teacher's Association.