Chihuahuan Desert Biotic Study

Introduction

Chihuahuan Desert Map The Chihuahuan Desert is the easternmost, southernmost, and largest North American desert. For background information on the Chihuahuan Desert go to:

The purpose of this activity is to study biodiversity in the Chihuahuan Desert. Your students will be conducting a transect study. They will be making observations along a line laid out deliberately in a study area. They will be gathering quantitative data about the flora and fauna of this particular area. This lesson only addresses the biotic factors in the area of study and should be done in conjunction with the lesson on gathering abiotic information.

Student Outcomes

Students will be working in small groups to set up a transect in order to sample biotic factors in the Chihuahuan Desert ecosystem.
Students will identify flora and fauna present along the transect.
Students will record their findings.
Students will discuss their findings in a large group.

Content Area and Grade Levels

This lesson can be used with second graders and up. The teacher will have to present the concept of biodiversity. The teacher will also need to model the use of identification guides and the Plant Transect and Animal Transect Data Records.

Content Standards

Science Standards

Standard 1 - Understands basic features of the Earth.
Standard: 7 - Understands how species depend on one another and on the environment for survival.
Standard: 4 - Knows about the diversity and unity that characterize life.
Standard: 14 - Understands the nature of scientific knowledge.
Standard: 15 - Understands the nature of scientific inquiry.

Thinking and Reasoning Standards

Standard: 3 - Effectively uses mental processes that are based on identifying similarities and differences (compares, contrasts, classifies).
Standard: 4 - Understands and applies basic principles of hypothesis testing and scientific inquiry.

Implementation Overview

This lesson is set up for use in one class with a minimum duration of one hour. You may do the activity as often as possible, and at least once per season. Students are divided into groups of four or five and given specific information to research. They analyze their findings and prepare a group presentation that is given to the rest of the class. This lesson can be part of a larger project or stand alone as a project in itself, but should always be done in conjunction with an abiotic study. The procedures follow:

Form groups of four or five students.
Have the groups negotiate where to lay down the transect.
TIP: The transect must be by a Creosote bush as this is an indicator plant of the Chihuahuan Desert.
Laying out the transect:
a) place one stake at one point, measure out 10 meters, and place another stake;
b) connect the 2 stakes with rope.
TIP: The students will be counting only those plants and animals, or evidence of them, that are actually touched by the transect, or found lying under and/or over it.
Identify all the plants along the transect:
a) count the number of wildflowers, trees, shrubs, cacti and grasses;
b) try to identify each one by using the identification books;
c) total all your plants up;
d) divide this total by the total number in each group to determine percentage;
e) record this information on the Plant Transect Data Record;
f) draw and label the plants you find.
Identify all the animals along the transect:
a) count the number of reptiles, amphibians, insects, spiders, mammals and birds;
b) try to identify each one by using the identification books;
c) look for tracks, holes dug, scat;
d) look for insects on the surface;
e) dig holes to find burrowing insect or other animals;
f) record this informatin on the Animal Transect Data Record;
g) draw and label the animals you find evidence of or actually see.
Debrief the small groups in one large group:
a) ask questions about their findings;
b) compare and contrast data;
c) ask the students to make inferences and hypotheses.

Resources Needed

Each group will need the following materials:

10 m rope
meter stick
animal log
plant log
clipboard, paper and pencils
hand lens
identification guides:
- Bowers, Janice Emily.100 Desert Wildflowers. SW Parks and Monuments Association, 1989.
- Fischer, Pierce C. 70 Common Cacti. SW Parks and Monuments Association, 1989.
- MacMahon, James A. Deserts. New York: Alfred A. Knopf, 1994.
- Pearce, Q.L. Animal Footnotes:A Nature's Guide.
- Taylor, Dave. Endangered Desert Animals. Crabtree Publishing Co., 1993.

Entry Level and Skills

Students will need some basic understanding of how to collect information and organize it. Students will use an Animal Transect Data Record and a Plant Transect Data Record which need to be printed out. Teachers will need some experience in organizing students into groups and keeping them on task. They will also need access to the Internet and should be familiar with the flora and fauna of the Chihuahuan Desert (if not familiar, use this opportunity to learn with the students).

Evaluation

Students can be evaluated on research methods (how they verified data, how they organized their data, what their conclusions are, etc.), on group collaboration and participation, on effective use of time, and on their preservation of information for future use or reference. Students can also use forms of self and peer evaluations. For further methods of assessment or evaluation, see the National Science Standards of Assessment.

Conclusion

This lesson will teach students how to collect data through investigation, how to analyze, organize and present information to others, and how to understand the diversity in the biotic elements of the Chihuahuan Desert. It will also reinforce plant and animal identification.

This lesson created by Miriam Martínez and Dolores Varela-Phillips, Los Padillas Elementary School.