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Teaching About EcosystemsDavid L. Haury July 2002 |
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When someone asks us where we are from or what we do, most of us mention the town or city where we live, our occupation, where we attended school, or our family heritage. We respond in terms of human communities, cultures, and geopolitical boundaries. We seldom, if ever, describe ourselves in terms of our ecological status in the natural world. We humans have so completely ordered, designed, and defined our physical environs and social milieu that our ecological connections have slipped from consciousness. Perhaps this is why we seem so unaware of our impact on nature and our rapid destruction of natural systems. We simply do not perceive ourselves as being part of the natural order of beings. All of us live within ecological systems, or ecosystems, and through our commerce, food distribution, and use of natural resources we each indirectly participate in the custodianship of many ecosystems worldwide. Ironically, we are simultaneously the most potent forces within most ecosystems, and yet nearly oblivious to the ecological effects of our daily lifestyles. There has never been a time when a deep understanding of ecosystems and our roles within them has been more critical. Indeed, the world’s freshwater ecosystems are so degraded that their ability to support plant and animal life, including humans, is viewed by many as being in peril (Revenga, Brunner, Henninger, Kassem, & Payne, 2000). Learning about ecosystems is more than an expected focus in biology classes; it has become a study in survival. Ecosystems
are functional units of interacting abiotic, biotic, and
cultural (anthropogenic) components. All natural
ecosystems are open systems where energy and matter are
transferred in and out through the complex interactions
of energy, water, carbon, oxygen, nitrogen, phosphorus,
sulfur, and other cycles.
Unfortunately, many scientists contend, we humans
have disrupted the balance of transfers across ecosystem
boundaries. In
addition to learning our place within ecosystems, we
must learn to become better stewards and managers of
ecosystems. A
history of the ecosystem concept has been presented by
Bocking (1994). Unfortunately,
some concepts related to ecosystems—food web,
ecological adaptation, carrying capacity, niche—are
complex and lead to misconceptions among students
(Munson, 1994). Ecosystems in the Curriculum
Ecosystems receive considerable attention in national
curriculum standards and guidelines.
Both the National
Science Education Standards (NSES, National Research
Council, 1996) and the Excellence in Environmental Education: Guidelines for Learning (K-12)
(EEE, North American Association for Environmental
Education, 2000) use systems as an organizing concept.
Within the Standards,
the unifying concepts and processes for K-12 content standards include
“Systems, Order, and Organization”, and within the
EEE Guidelines, one of the four organizing strands is “Knowledge of
Environmental Processes and Systems” that includes
specific guidelines regarding ecosystems and their
components. The
Standards also
include several content standards pertaining to
ecosystems in the Life Science strand and the Science
in Personal and Social Perspective strand. Following
is a overview of the standards and guidelines
specifically relating to ecosystems. Standards
and Guidelines for Grades 5-8 Content
Standards
(NSES) • The complementary nature of structure and function within ecosystems. • All populations living together and the physical factors with which they interact compose an ecosystem. • Populations of organisms can be categorized by the
function they serve in an ecosystem, and food webs
identify the relationships among producers, consumers,
and decomposers in an ecosystem. • Energy entering ecosystems as sunlight is transferred by
producers into chemical energy through photosynthesis.
That energy then passes from organism to organism in
food webs. • The number of organisms an ecosystem can support depends on the
resources available and abiotic factors.
The
Living Environment Guidelines
(EEE) • Define ecosystem and give examples of connections among organisms at this level of organization. • Summarize how abiotic and biotic components in combination influence the structure of an ecosystem. • Describe how energy, which enters ecosystems as sunlight, changes form and is transferred in the exchanges (production, consumption, and decomposition) that comprise food webs. Standards and Guidelines for Grades 9-12 Content Standards
(NSES) • Energy flows through ecosystems in one direction, from photosynthetic organisms to herbivores to carnivores and decomposers. •
Organisms
both cooperate and compete in ecosystems. The
interrelationships and interdependencies of these
organisms may generate ecosystems that are stable for
hundreds or thousands of years. •
Human beings live within the world's ecosystems.
Increasingly, humans modify ecosystems as a result of
population growth, technology, and consumption. Human
destruction of habitats through direct harvesting,
pollution, atmospheric changes, and other factors is
threatening current global stability, and if not
addressed, ecosystems will be irreversibly affected. •
The distribution and abundance of organisms and
populations in ecosystems are limited by the
availability of matter and energy and the ability of the
ecosystem to recycle materials •
Natural ecosystems provide an array of basic
processes that affect humans. Those processes include
maintenance of the quality of the atmosphere, generation
of soils, control of the hydrologic cycle, disposal of
wastes, and recycling of nutrients. Humans are changing
many of these basic processes, and the changes may be
detrimental to humans. The
Living Environment Guidelines (EEE) •
Explain ecosystem change with respect to
variables such as climate change, the introduction of
new species, and human impacts; and explain processes
such as desertification and soil formation as mechanisms
for such change. There
are many additional standards and guidelines that
directly or indirectly relate to ecosystems, but this
overview provides the basic conceptual framework to be
developed through the school curriculum.
It should be noted that the framework includes
attention both to basic concepts pertaining to
ecological systems as well as the impacts of human
activity on ecosystem change and stability.
Beyond the Textbook and Standards As Noss, LaRoe, and Scott (1995) have so convincingly documented, there have been severe declines in the area and natural quality of terrestrial and aquatic ecosystems in all regions of the United States. Habitat loss, ecosystem degradation, and ecosystem fragmentation have led to great losses in biodiversity. Indeed, entire ecosystems are endangered along with individual species. Though management efforts have led to the gradual recovery of some ecosystems, there is a need for citizens to gain a greater sense of their ecological connections and the long-term impacts of human activities. Schools and individual teachers are responding by developing programs and learning experiences that focus on ecosystems, field study, and examinations of human impact through actions and decisions. Tracy and Glaser (1999) described an immersion program in which K-5 students meet all curriculum guidelines through investigating, monitoring, and restoring schoolground habitats and local ecosystems. Lewis (1999) focuses on an analysis of human impacts through ecosystem surveys that engage students in formulating and testing hypotheses about human impacts. Freeman (2002) describes a unique approach to studying the human impact on ecosystems through ongoing study of an artificial aquatic ecosystem by students in grades 7 through 12. She describes activities that are woven into the curriculum of integrated science, biology, chemistry, and physics over a six year period. Another curriculum approach that combines study of ecosystems with consideration of human impacts and decision making is offered by the Forest Service Employees for Environmental Ethics (2000). Their Secret Forest Experience Curriculum is designed for middle school students and engages students in five science-based projects related to ecosystems of western U. S. forests. The materials are available in both English and Spanish. Finally, Brodie (1995) offers background and activities related to a unique ecosystem, the Great Basin of the western United States, that draws attention to web of life within deserts. This unit of study is appropriate for upper elementary and middle school students, and includes both a historical perspective and visions of future options in terms of human impact on this arid ecosystem.
Reaching Beyond the Science Classroom To supplement the traditional content on ecosystems in science classes, some groups have developed instructional materials and activities that integrate ecosystem concepts with a range of topics and subjects. Following are selected examples of materials that are available to teachers. Adams, M., Brickell, R., & Hanophy, W. (Senior Eds.). (1995). Ecosystem matters: Activity and resource guide for environmental educators. Washington, DC: U. S. Department of Agriculture. [ED 403 116] This compendium of activities is intended for classroom teachers, nature camp instructors, scout leaders, forest rangers, naturalists, and others who are helping learners make conscious decision that lead to the long-term stewardship of natural resources. This guide was designed to supplement existing courses and programs concerning ecological matters, and the activities focus on ecosystem management. The interdisciplinary activities relate to topics in social studies, drama, language arts, geography, history, math, physical education, and science, and the activities are categorized by grades K-3 (13 activities), grades 4-5 (20 activities), grades 6-8 (25 activities), and grades 9-12 (13 activities. Lewis, J. (1999). People, growth, and endangered ecosystems: Exercises in biodiversity, grades 6-12. Tallahassee: Florida State Department of Environmental Protection. [ED 434 013] This document features interdisciplinary activities
that combine the study of biology with music, art,
language arts and social studies. The activities are
aimed at students in middle school through the first two
years of high school. All activities can be conducted in
the classroom or outdoors near the school. Selected World Wide Web Resources Living Things: Habitats and Ecosystems A resource of the Franklin Institute http://www.fi.edu/tfi/units/life/habitat/habitat.html Earth on Edge: EcosystemsA Web resource associated with Bill Moyers Reports on PBS that examines the status of the world’s ecosystems http://www.pbs.org/earthonedge/ecosystems/index.html Exploring Ecosystems OnlineAn electronic field trip for grades
7-12 provided by the Smithsonian
Institution's National Museum of Natural History http://www.bsu.edu/teachers/academy/ecosystems/ Ecosystems of Our WorldAn interactive Think Quest resource featuring ten different ecosystems http://library.thinkquest.org/11353/ecosystems.htm Freshwater EcosystemsAnd extensive directory of Web resources and lesson plans on aquatic ecosystems in Canada and the United States http://www.eagle.ca/~matink/themes/Biomes/watereco.html EcosystemsA Learning Web resource provided by the U.S. Geological Survey http://interactive2.usgs.gov/learningweb/explorer/topic_eco_links.asp Backyard Science: How Ecosystems WorkOnline teaching guide for an activity suitable for students in grades 5-12. http://www.pbs.org/safarchive/5_cool/galapagos/g52e_ecosystems.html EcosystemsA lesson plan from Discovery.com suitable for students in grades 6-8. http://school.discovery.com/lessonplans/programs/yosemite/ Finding Information in the ERIC DatabaseThere are many records in the ERIC Database pertaining to ecosystems, but it takes a little searching to find them. The term ecosystem is not used to index records in ERIC, so it is best to search using ecology as a Descriptor, combined with ecosystem or ecosystems as keywords. You can narrow your search by combining these terms with one or more of the following Descriptors: teaching methods, instructional materials, experiential learning, hands on science, environmental education, or similar terms. You can further narrow your search by using education level Descriptors, such as elementary education, middle schools, intermediate grades, or junior high schools, or individual grade levels. You can search the database on the Web at http://ericir.syr.edu/Eric/adv_search.shtml. ReferencesBocking, S. (1994, July-August). Visions of nature and society: A history of the ecosystem concept. Alternatives, 20 (3), 12-18. [EJ 491 835] Brodie, J. M. (1995, May). The big empty. Science & Children. Also available online at: http://www.blm.gov/education/great_basin/great_basin.html Forest Service Employees for Environmental Ethics. (2000). The secret forest experience. Eugene, OR: Author. Available online at: http://www.fseee.org/project.cfm Freeman, C. C. (2002). Building an ecosystem. Access Excellence, Activities Exchange, The National Health Museum, http://www.accessexcellence.org/AE/AEC/AEF/1995/freeman_ecosystem.html. Lewis, J. K. (1999). Surveying an ecosystem: An exercise for high school biology students. Tallahassee, FL: Florida State Department of Environmental Protection. Munson, B.H. (1994, Summer). Ecological misconceptions. Journal of Environmental Education, 25 (4), 30-34. National Research Council. (1996). National science education standards. Washington, DC: National Academy Press. (Available online at: http://www.nap.edu/readingroom/books/nses/html/) North American Association for Environmental Education. (2000). Excellence in environmental education: Guidelines for learning (K-12). Washington, DC: author. Noss, R. F., LaRoe, E. T., & Scott, J. M. (1995). Endangered ecosystems of the United States: A preliminary assessment of loss and degradation. Biological Report 28. Washington, DC: USDI National Biological Service. (Available online at: http://biology.usgs.gov/pubs/ecosys.htm) Revenga, C., Brunner, J., Henninger, N., Kassem, K., & Payne, R. (2000). Pilot analysis of global ecosystems: Freshwater systems. Washington, DC: World Recources Institute. (Available online at: http://www.wri.org/wr2000/freshwater_page.html) Tracy, J., & Glaser, K. (1999, Fall). Ecology project learning. Green Teacher, no. 59, 5-9.
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