Spiders: An Organism for Teaching Biology

Part A

Unit Objectives:
In this unit, the students will explore some basic ecological (energy transfer, predator-prey relations, abiotic-biotic interactions, etc.) concepts using spiders. They model real scientific processes while caring for and studying spiders both in the classroom and in the field. At the end of this unit, students will be able to:

1. define the predator-prey relationship.
2. identify links in the food chain/web and distinguish between producer, consumer (primary/secondary), and decomposers.
3. give examples of how predators and prey put selective pressures on each other contributing to coevolution in an arms race of which can catch and which can avoid being caught better.
4. discuss regulation of numbers of prey and predators.
5. describe ways in which all organisms interact with the environment and with other organisms (abiotic and biotic factors).
6. describe how an event which affects one organism affects others, directly or indirectly.
7. group organisms by how they obtain their food (energy)-- for example, sit and wait, ambush, stalk, etc.
8. explain how the science process and experimentation is used to answer questions.
9. identify plants as the base of all food chains/webs.
10. outline the steps used in a mark and recapture study to determine population numbers.
11. identify the assumptions behind a mark and recapture study and identify appropriate situations this would be used for.
12. apply concepts to new situations.
    
    

 

Getting Started
Find out what students already know about spiders.
Make a list on the board. Things they might say: 8 legs, many eyes, poisonous, dangerous, black widows are dangerous, there are big wolf spiders and tarantulas, make webs, eats bugs. Ask students to write at least one question concerning spiders. Collect and read through some of them. Do not offer answers to their questions. Write the questions down on butcher paper or some other permanent record to be referred to later by the students for ideas for their experiments. Add to this list as questions and new ideas arise in class.

Getting comfortable.
Be comfortable and relaxed in the presence of spiders. Model appropriate handling of spiders and respect for living organisms. Spiders really aren't as dangerous as most people believe. Most are reluctant to bite--why should they waste good venom on something too big to be eaten?! Still care and caution should be taken because of possible allergic reactions to a spider's bite and venom. However, spend some time to build student confidence. Let the students enjoy a pet tarantula. Hold it to show off during class. If students want to hold the tarantula have them come in during lunch or after school when there is not so much excitement. Jumping spiders are easy to handle, do not readily bite, and can be held in front of students to show off. Show pictures or slides. Have fun!

 

The University of Arizona
Department of Biochemistry and Molecular Biophysics
General Biology Program for Secondary Teachers
warder@email.arizona.edu