Chihuahuan Desert Abiotic Study

Content Area | Standards | Implementation | Resources | Entry Skills | Evaluation | Conclusion | Student Version

Introduction

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

• The Chihuahuan Desert
• An Introduction to the Chihuahuan Desert
• Chihuahuan Desert Resources on the Web
• El Paso Online Bio Project
• The Chihuahuan Desert through time

The purpose of this activity is to study biodiversity in the Chihuahuan Desert. Your students will be gathering abiotic information. The diversity of any community is related to the abiotic elements found in that ecosystem. This lesson should be done in conjunction with the biotic study.

Student Outcomes

• Students will be working in small groups to set up a transect in order to sample abiotic factors in the Chihuahuan Desert ecosystem.
• Students will gather weather data along the transect.
• Students will collect soil samples along the transect.
• Students will gather percolation rates 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 need to model the use of the equipment used and the Chihuahuan Desert Sampling Log.

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 twenty minutes. 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 a biotic study. It is important that when the students are gathering the abiotic data for their study area that they do not disturb the soil along the transect as this will affect the results of the biotic study. It is recommended that you set up the transect and do the biotic study before you gather the abiotic data. The procedures for the abiotic study follow:

1. Form groups of four or five students.
2. 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.
3. 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.
4. Collecting weather data (at one of the stakes):
   a) take air temperature by leaning or holding thermometer facing North for at least 2 minutes;
   b) tie a long piece of engineering tape to the stake to see the wind direction;
   c) use the Beauford wind scale to estimate wind speed;
   d) determine cloud cover and type;
   e) record this data on the Chihuahuan Desert Sampling Log.
5. Collecting soil sample (at the middle of the transect):
   a) fill up a plastic sandwich bag with a soil sample (to be analyzed later);
   b) record the time of day;
   c) record the soil temperature at the soil surface and at 5cm., 10cm.,15cm. and 20cm;
   d) record the air surface temperature.
6. Collecting Percolation Rate (at the middle of the transect):
   a) work each can into the ground 2 cm;
   b) pour a measured amount of water into each can;
   c) measure the time required for all the water to enter the soil;
   d) record it for each can and average the results.
7. 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
• Chihuahuan Desert Sampling Log
• clipboard, paper and pencils
• weather bag:
  • cloud chart
  • Beauford wind scale
  • thermometer
  • compass
  • engineer's tape
• soil bag:
  • trowel
  • spade
  • calibrated soil thermometer
  • sandwich bag
  • permanent marker for labelling
• percolation bag:
  • 2 soup cans
  • water container
  • measuring cup

Entry Level and Skills

Students will need some basic understanding of how to collect information and organize it. Students will use a Chihuahuan Desert Sampling Log which needs to be printed out. Teachers will need some experience in organizing students into groups and keeping them on task. They will also need to be familiar with the equipment used in this lesson.

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 record the abiotic elements of the Chihuahuan Desert.

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