ESCAMILLA: GUIDED INQUIRY IN SUSTAINABILITY
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Guided Inquiry in Sustainability:
Enhancing student knowledge of desertification, biodiversity, and sustainability
Dr. Rebecca Escamilla
El Paso Community College, Northwest Campus
Author Note
Dr. Rebecca Escamilla, Assistant Professor in Biology, El Paso Community College,
Northwest Campus.
I would like to sincerely thank my students in my Biology 1107 class for all of their
willingness to participate. Their help was invaluable to my research project. I would also like to
thank my Faculty mentor, Dr. Jose Pacheco from Phase I and Phase II. His help and guidance
were invaluable to the final outcome of this project
Correspondence concerning this article should be addressed to Rebecca Escamilla Ph.D.,
Department of Biology, El Paso Community College, Northwest Campus,
P.O. Box 20500, El Paso, Texas 79998-0500. E-mail: [email protected]
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Abstract
Our planet is currently facing environmental challenges that are projected to worsen in
the future. As citizens, we must be informed about these challenges and understand our role to
ensure the sustainability of our planet. Engaging community college students with ecological
concepts that enhance their understanding of local to global environmental challenges and the
concept of sustainability is challenging but critical to empowering and readying the next
generation of environmental scientists and problem solvers. In this paper, I present and evaluate
a new inquiry-based lab activity that aimed to develop holistic understanding of environmental
challenges, and the concept of sustainability. The activity is focused on desert ecosystems and
desertification, and experimental manipulations that explore this local environmental challenge,
and how ecosystem restoration can improve sustainability. Student performance was measured
using pre- and post-tests to conduct a knowledge and attitude assessment. I evaluated a)
ecological content knowledge acquisition, b) appreciation of ecology as a science, c)
appreciation for statistics used by ecologists, d) attitude associated with ecological self-efficacy
(confidence in their ability to take actions beneficial to the environment) and e) attitude
associated with statistical self-efficacy (confidence in their ability to apply statistics
competently). Significant increases and large effect sizes were observed in knowledge
acquisition, and environmental efficacy. I infer, therefore, that the lab activity effectively
enhanced student content knowledge, their confidence in understanding the importance of
desertification and sustainability, and improved their confidence in being able to apply this
knowledge to help find solutions.
Keywords: Environmental challenges, sustainability, inquiry-based learning, desertification
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INTRODUCTION
Dramatic human and environmental change is altering the world we live in and the
sustainability of ecosystem goods and services (Millennium Ecosystem Assessment, 2005). As
well as human induced climate change and sea level rise (IPCC 2007), among the most important
environmental changes is the desertification of arid and semi arid regions globally, which
commonly results in the replacement of relatively productive grasslands with unproductive
shrublands (Barger et al., 2011). This vegetation shift is associated with many ecosystem
properties and processes that appears to positively reinforce the altered ecosystem state (Peters
and Havstad, 2005), suggesting that critical tipping points have been passed and a reversal of
such trends will be difficult, if not impossible (Bestelmeyer et al., 2009). Similar scenarios have
now been documented for a range of other changes in the environment that are unusual
compared to the environmental change that has occurred on Earth over the past few million years
and some researchers suggest that the Earth System is entering a new state – the anthropocene
(Crutzen and Steffen 2003; Ehlers and Krafft 2006). Although uncertainty exists as to how this
state change will affect humans (IPCC, 2007), the current generation of students will be among
the first societal leaders and decision makers to witness and make critical environmental
decisions in this new state. For these reasons, higher education has been challenged to play a
critical role in catalyzing societal change towards environmental sustainability (Chapin et al.,
2011; Junyent and Geli, 2010). Thus, there is a need to both improve scientific understanding of
the future state of the Earth System and how humans will need to adapt, and simultaneuously
develop new education capacities that focus on environmental challenges and problem solving
geared toward sustainability (National Research Council, 2009). Uniting the teaching of ecology
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with discussions of real world environmental issues engages students (Pallant, 1996; Gill and
Burke, 1999; Battles et al., 2003), which along with preparing them to think holistically and
work interdisciplinarily, is key to empowering students to deal with the ecological and
environmental challenges of the 21st century (Chapin et al., 2011; Tilbury, 1995). In addition,
education based on the environment and environmental issues is well suited for student-centered
and activity-based learning (Tilbury, 1995), which aligns well with the National Research
Council’s (NRC, 2000; 1996) endorsement of a science curriculum that promotes active learning,
inquiry, and other instructional methods that engage students.
Problem
There is a need to develop new education experiences that focus on improving student
understanding of future environmental challenges, and problem solving for sustainability of the
Earth. One of the classes I currently teach is the Major’s Introductory Biology II course (BIOL
1307/1107) which provides the ideal opportunity to provide these experiences. Currently, there is
no lesson or activity in this course that introduces these topics, and few attempts have been made
to provide them despite its importance.
Solution
In this paper I describe the analysis of an inquiry-based lab activity that was developed
with the aim of improving holistic understanding of environmental problems, and the concept of
sustainability. I chose to use desert ecosystems and desertification as focal themes because this
study was performed at El Paso Community College (EPCC) situated in the northern
Chihuahuan Desert on the US-Mexico border where desertification and land use change has
altered ecosystems (Barger et al., 2011) and affected sustainability (Verstraete et al., 2009). The
lab activity acquainted community college biology students with local desert ecosystems and
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desertification, and experimental manipulations that explore how ecosystem restoration might
improve sustainability. It also allowed the students to experience the utility of the scientific
methodology to solve problems in science.
METHODS
Experimental design
I designed an inquiry-based lab activity that focused on a) Chihuahuan Desert
ecosystems, and b) restoration ecology and sustainable living practices. The lab activity was
presented during scheduled class time on the EPCC Northwest campus with the aid of Power
Point presentations, documentary movies, and experimental testing. Students were introduced to
global and local environmental challenges currently faced, such as climate change and
desertification. Next, students were presented with the effects that desertification has on plant
biodiversity and sustainability. Essentially, most nutrient rich soil is localized under shrub
canopies, with bare space (most of the ground cover) is void of vital plant nutrients (see Photo
1). To test this concept, students were asked to generate a research question and hypothesis based
on the information presented, formulate a method protocol to test the hypothesis, implement the
protocol and collect data, analyze data, formulate a valid conclusion based on the data collected,
and communicate their findings.
During the Spring 2015 semester, I introduced the inquiry-based lesson into a Biology
1107 Lab at EPCC Northwest campus (experimental group). The data collected from this group
was compared to a Biology 1107 lab at EPCC Northwest campus that did not receive the lesson
(control group). Participants included male and female adults, 18 years of age and over, and
enrolled in Biology 1107 courses at EPCC Northwest Campus. Recruitment from the class pool
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was conducted through oral invitation by the author of this study who also acted as the lead
instructor for the courses. To minimize coercion, extra credit was awarded to students for
participation in the study. If students chose not to participate, they were allowed to earn extra
credit through alternative means. Active written consent was obtained from all participants. Due
to IRB restrictions, we were unable to collect demographic data, however the classes was typical
for EPCC, where 84.7% of the student body is Hispanic.
A pre-test was given to both groups prior to the lab activity to assess students’ baseline
knowledge and attitudes. Following the lab activity for the experimental group, an identical post-
test was given to both groups to allow for the relative impact of the lab activity to be assessed.
There were two parts to the pre- and post-test. The first was a knowledge assessment that
included multiple choice content knowledge questions based on the topics and that assessed
changes in student knowledge. The second part was an attitude assessment that included a 5-
point Likert scale questionnaire that assessed the change in student attitudes. Students ranked
themselves on a scale of 1 to 5 (5 representing strongly agreeing and 1 strongly disagreeing) in
response to various statements associated with the topics discussed in the lab activity.
Data analysis
For the knowledge assessment, content knowledge was scored by marking answers
correct/incorrect. The percentage of correct answers in the pre- and post-tests were then
calculated for both the control and experimental groups.
For the attitude assessment, the Likert survey questions were broken into 5 subcategories:
a) ecological content knowledge, b) appreciation of ecology, c) ecological efficacy, d)
appreciation of statistics, and e) statistical efficacy. The mean score and standard deviation was
calculated for each category and for all categories combined to get the overall attitude
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assessment. Scores from the content knowledge and attitudinal tests were then combined to
generate an omnibus score for each student’s pre- and post-test (see Equation 1 below). Overall
mean scores and standard deviation were calculated for both the control and experimental
groups. Using independent 2-sample t-tests and the statistical software Minitab (V17), both pre-
and post-tests for the control and experimental groups were analyzed and compared to determine
if participants’ content knowledge and attitude changed significantly.
Equation 1: Total score = (((a / b) + (c / d))/2)*100, where a = total correct, b = total
questions, c = total attitude score, and d = total points of the attitude portion of the test.
Effect sizes were calculated to assess the effectiveness of the lab activity. Effect sizes
describe ‘how well the lesson worked’, not just ‘how the mean scores differed’ (Coe, 2000). For
this analysis, we used Equation 2 (see below) to calculate Cohen’s effect size (d) and categorized
results using Cohen’s (1992) classification: small (d >= 0.20), medium (d >= 0.50), or large (d
>= 0.80).
Equation 2: D = (x - y) / z, where x = mean of the post-test, y = mean of the pre-test, and z =
pooled standard deviation.
RESULTS
Significant increases in mean scores were observed between pre- and post-tests, and
between control and experimental groups in content knowledge acquisition, overall attitude, and
environmental efficacy. These results suggest the lab activity had a significant impact on student
learning.
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Knowledge Assessment: Content knowledge and ecological content knowledge
Students’ content knowledge increased significantly (Fig. 1A). For the experimental
group, mean scores for the pre- and post-tests were 57.1 and 74.4 respectively (t-value = -3.58;
p-value < 0.001). The mean scores for the control group pre-and post-tests were 40.6 and 40.7.
The pre-test mean scores for the control and experimental groups were compared, and there was
a significant difference between them (t-value = -2.89; p-value = 0.007). With this information,
we can infer that there was a significant difference between the post-tests for the control and
experimental group. The effect size was large for this category (d = 1.31) (Table 1).
The results indicate a significant increase in ecological knowledge (Fig. 1B). For the
experimental group, mean Likert scores for the pre- and post-tests were 1.9 and 2.7 respectively
(t-value = -2.28; p-value < 0.05). The mean Likert scores for the control group pre-and post-tests
were 1.9 and 1.7. With this information, we can infer that there was a significant difference
between the post-tests for the control and experimental group. The effect size was also large for
this category (d = 0.81) (Table 1).
Attitude Assessment: Efficacy, appreciation, and attitude
Ecological efficacy increased significantly for this lab activity (Fig. 1C). The mean scores
for the experimental group pre- and post-tests were 1.8 and 3.2 (t-value = -4.03; p-value <
0.001). The mean scores for the control group pre- and post-tests was 1.9 for both. With this
information, we can infer that there was a significant difference between the post-tests for the
control and experimental group. The effect size was also large for this category (d = 1.31) (Table
1).
There was no significant change in ecological appreciation between the experimental pre-
and post-tests (mean scores are 4.1 and 4.2 respectively), and between the control pre- and post-
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tests (mean scores are 3.6 and 3.5 respectively). However, there is a significant different
between the experimental and control (t-value = -2.67; p-value < 0.05), and there was no effect
size (d = 0.11) (Fig. 1D; Table 1). Changes in statistical appreciation (Fig. 2A) within
experimental and control groups was not significant with mean scores in pre- and post-tests
being 4.2 and 4.4, and 3.6 and 3.5, respectively. However, there is a significant different between
the experimental and control groups (t-value = -2.14; p-value < 0.05). Changes in statistical
efficacy (Fig. 2B) was not significant in any of the comparisons (experimental and control pre-
and post-test mean scores are 3.0 and 2.9, and 3.1 and 3.0, respectively).
Mean scores for assessing overall changes in student attitudes in pre- and post-tests for
the experimental group were 3.2 and 3.6, and 3.0 and 2.90 for the control group with no
significant differences between the groups pre- and post-tests. However, there is a significant
change between the experimental and control groups post-test (t-value = -3.11; p-value < 0.05).
In addition, there was a medium effect size (d = 0.69) (Fig. 2C, Table 1).
Overall assessment
For the overall assessment, we combined the knowledge and attitude assessment. The test
scores increased significantly between the experimental pre- and post-tests, and between the
control and experimental groups (Fig. 2D). Mean scores for the experimental group pre- and
post-tests were 60.8 and 72.9 which showed a significant difference (t-value = -3.44; p-value =
0.002), and 50.2 and 49.1 for the control group with no significant difference. There was a
significant difference between the experimental and control groups post-test (t-value = -5.91; p-
value < 0.001), and had a large effect size (d = 1.26 (Table 1).
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DISCUSSION
In this study I aimed to assess how an inquiry-based lab activity that was developed to
improve holistic understanding of environmental problems, and the concept of sustainability
impacted student learning. I measured student performance in knowledge and attitude through a
series of pre- and post-tests that specifically tested for a) ecological content knowledge
acquisition, b) appreciation of ecology as a science, c) appreciation for statistics used by
ecologists, d) attitude associated with ecological self-efficacy (confidence in their ability to take
actions beneficial to the environment) and e) attitude associated with statistical self-efficacy
(confidence in their ability to apply statistics competently).
Both content knowledge and ecological content knowledge increased significantly
between the pre- and post-tests for the experimental group and between the control and
experimental groups’ post-tests, suggesting students gained knowledge of the ecological
concepts related to desert ecosystems, desertification, and sustainability. They also had large
effect sizes. For changes in attitude, evaluation shows a statistically significant increase between
control and experimental post-tests, and a medium effect size. This suggests students’
appreciation and confidence in their knowledge about desert ecosystems and desertification, and
their ability to apply ecological and technological concepts improved some overall. Attitudinal
changes that had the largest effect sizes included students’ confidence in their ecological content
knowledge, and ecological self-efficacy. Self-efficacy is one's belief in their ability to succeed in
specific situations and plays a major role in how goals, tasks, and challenges are approached
(Bandura, 1997). Ecological appreciation had no effect size, but students initially scored high on
the pre-test, suggesting students already had a high appreciation for environment prior to this lab
activity. Based on the results from this study, I infer that the lab activity was effective in
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improving content knowledge, and changing the attitude of the students in terms of their holistic
understanding of environmental challenges, and the concept of sustainability.
The lab activity presented in this study includes inquiry-based learning approaches that
have been shown to be particularly effective in learning activities tailored to underrepresented
and underserved populations (Haury, 1993; Rosebery et al, 1990; Rodriguez and Bethel, 1983).
Since the class I tested exemplified a typical EPCC classroom dominated by Hispanics, the
results of this study are not surprising and further exemplify the utility of inquiry based learning
for underrepresented populations. However, I did not use another teaching method so we cannot
quantify the potential outcome of inquiry versus non-inquiry based methods.
The lab activity developed and evaluated in this study further support the notion that
inquiry based learning improves student learning through improved content knowledge, and
attitudinal changes in efficacy. Such learning outcomes are needed to take on the many
challenges facing the next generation of environmental scientists and decision makers, so this
study therefore serves as a model for further curriculum development that focuses on advancing
scientific understanding combined with ecological efficacy, and the development of student
attitudes and appreciation towards the environment, making the students better able to face the
environmental challenges of the 21st century. Lastly, the lab activity in this study also supports
the National Research Council’s (2009) Vision and Change initiative to improve undergraduate
biology education for all students by incorporating the following criteria: 1) developing curricula
that integrates global environmental problems and relates these as real-world examples to
abstract biological concepts, 2) utilizing innovative pedagogy and create active learning
environments for students, and 3) integrating assessment and applying assessment data to
improve and enhance the learning environment.
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Future Directions
The original intent for the creation of this laboratory activity was to develop students’
holistic understanding of environmental challenges, and the concept of sustainability. As
citizens, they must be informed about these challenges and understand their role to ensure the
sustainability of our planet. Engaging students with ecological concepts that enhance their
understanding of local to global environmental challenges and the concept of sustainability is
critical to empowering and readying the next generation of environmental scientists and problem
solvers. One of the next steps for this lab activity is to improve the statistics portion of the lesson
to better acquaint the students with the importance of statistics in biology, and science. In
addition, I would like to add a skills assessment to the protocol, which would evaluate the
students’ ability to apply their knowledge in real world scenarios that force them to provide
solutions to some of these environmental challenges.
Additional Outcomes
As a result of the effectiveness of this laboratory exercise, it was included in the creation
of the new Biology 1107 Laboratory Manual custom edition for El Paso Community College
(EPCC), currently utilized at the Mission del Paso, Northwest, Rio Grande, and Valle Verde
campuses (see Appendix A).
References
BANDURA, A (1997). Self-efficacy: the exercise of control. W.H. Freeman and Company, New
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KNAPP (2011). Woody plant proliferation in North American drylands: a synthesis of
impacts on ecosystem carbon balance. Journal of Geophysical Research 116: 1-17.
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and-transition models for heterogenous landscapes: a strategy for development and
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AL. 2011. Earth Stewardship: science for action to sustain the human-earth system.
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COE, R. 2000. What is an effect size? A guide for users. Draft version available at
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EHLERS, E., AND T. KRAFFT. 2006. Managing global change: earth system science in the
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GILL, R.A., AND I.C. BURKE. 1999. Using an environmental science course to promote
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HAURY, D.L. 1993. Teaching science through inquiry. ERIC Clearinghouse for Science
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JUNYENT, M. AND A.M. GELI DE CIURANA. 2008. Education for sustainability in
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MILLENNIUM ECOSYSTEM ASSESSMENT. 2005. Ecosystems and human well-being:
desertification synthesis. World Resources Institute, Washington, D.C., USA.
NATIONAL RESEARCH COUNCIL. 2009. Vision and change in undergraduate biology
education: a call to action. National Academy Press, Washington D.C. 100 p.
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PALLANT, E. 1996. Assessment and evaluation of environmental problems: Teaching students
to think for themselves. Journal of College Science Teaching 26: 167-172.
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RODRIGUEZ, I. AND L.J. BETHEL. 1983. An inquiry approach to science and language
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Photo 1. Chihuahuan Desert shrubland highlighting areas of interspace, believed to be void of
nutrient rich soils, and canopy believed to be nutrient rich.
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Table 1. Cohen effect size scores and category for each assessment component of the surveys.
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Appendix A
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CChhaannggee iinn tthhee SSoouutthhwweesstt DDeesseerrttss
Objectives:
Know what land cover change is and be able to list examples of LCC
Understand the causes of land cover change
Know that desertification and shrub encroachment are the types of land cover change in
the southwest deserts
Be able to categorize the causes of land cover change as natural events or human impacts
Be aware of the potential consequences associated with human activities on
ecosystems/land cover
Know that deserts are valuable and have ecological goods and produce ecological
services
Know that human activities and natural events can change the natural world
Materials Required:
potting soil, soil from shrub interspaces, fertile soil from shrub canopies, seeds of fast
growing plants (sunflower, pea, wheat grass, etc.), water, beaker, 7 clear plastic cups,
trays, trowels or shovels, plastic Ziploc bags, ruler, marker, paper, pencils
Introduction Question: What is land cover change? How does it impact our environment, namely plant biodiversity? For many years, natural events such as changes in the earth’s climate, and human activities such as farming and cattle grazing, have changed the way the surface of the earth looks. Most changes have affected the vegetation on the ground, also called land cover, and transformed a once existing community of plants into an entirely new community. This is known as land cover change. The two types of land cover change are deforestation, or clearing of forests, and desertification. Desertification is the degradation of land in arid and dry sub-humid areas resulting in a loss of biodiversity and the land’s productive capability, and is the common type of land cover change occurring in the Chihuahuan Desert.
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Some of the consequences associated with desertification include loss of habitat, extinction of species, disruption of the water and nutrient cycles, and increased erosion with loss of valuable topsoil. One of the negative effects of land cover change is erosion. Plant roots provide stability to the soil on the ground. When the vegetation becomes less dense, the roots are no longer there to keep the soil in place. Water from heavy rains and wind can easily wash or blow the topsoil away. Topsoil is the top few centimeters of soil where a majority of the plant nutrients necessary for plant growth are found, and essentially lost through the process of erosion. In the Chihuahuan Desert, some of this eroded soil becomes trapped and accumulates underneath shrubs. This additional nutrient rich topsoil, along with decaying plant material, create islands of fertility. These islands found directly underneath shrub canopies are hypothesized to be richer in nutrients as compared to the soil in bare areas between shrubs (called interspace). In this lab you will be investigating the effects of erosion caused by desertification by testing the effects of both canopy soil (nutrient rich) and interspace soil (nutrient poor) on plant growth. You will attempt to grow a variety of seeds, including sunflower seeds, in these soil types.
Experimental Design Describe how you would like to test Interspace Soil versus Canopy Soil on plant growth: ______________________________________________________________________________ ____________________________________________________________________________________________________________________________________________________________ ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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Guidelines:
1. If your campus allows, go outside with Ziploc bags and trowels to collect canopy soil and interspace soil. Be sure to document the type of shrub you have collected the soil from. If you are unsure, please ask your instructor for assistance.
2. Gather the materials listed above. 3. Punch a few small holes at the bottom of 7 plastic container cups. 4. Fill the 7 clear plastic cups with soil, three with Interspace soil, three with
Canopy soil, and the last one with potting soil (control). Be sure to use the trowels provided to scoop up soil.
5. Be sure to label your cups appropriately. Be sure to include date and group name/number as well.
6. Place 3 sunflower seeds evenly spaced in each cup of soil. 7. Water the soil and place on the trays provided. 8. Make observations on what you will see each day including the day of seed
sprouting and plant height. Record you data in the table provided. Don’t forget to keep your plants watered to ensure proper growth conditions.
9. You will graph your data at the end of the experiment. You will be presenting this experiment as a written or oral presentation.
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Table 1. Seed and plant observations
Day Plants in Canopy Soil Plants in Interspace Soil Plants in Control Soil
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Questions What is land cover change? List some examples of land cover change? 1. 4. 2. 5. 3. What do you think can cause land cover change to occur? Generate a list and put the causes into two categories: one for human activities and the other for natural events. HUMAN ACTIVITIES NATURAL EVENTS
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What is erosion and how might it affect plant growth? Hint: What are the important soil nutrients for plants and what would erosion do to these nutrients? Additional Resources:
Analyzing land use change in urban environments http://landcover.usgs.gov/urban/info/factsht.pdf
Quantifying changes in the land over time http://landsat.gsfc.nasa.gov/education/resources/Landsat_QuantifyChanges.pdf
Earth as Home Lesson “An Island Home” http://interactive2.usgs.gov/learningweb/pdf/globalchange/island.pdf
http://www.geography4kids.com/files/land_erosion.html
http://teacher.scholastic.com/dirtrep/erosion/index.htm
http://teacher.scholastic.com/dirt/erosion/whateros.htm
http://www.brainpop.com/science/theearthsystem/erosion/preview.weml