Each of the first four volumes provides 25 probes with easy-to-follow steps for uncovering and addressing students’ ideas by promoting learning through conceptual change instruction. Probes cover topics such as physical, life, and Earth and space science; the nature of science; and unifying themes. Each volume on page 23 provides topic-specific probes. These invaluable books include teacher materials that explain content, identify links to standards, and suggest grade-appropriate ways to present materials so students learn the concepts accurately. Teachers, professional development coordinators, and college science and preservice faculty will find these resources essential and exciting.
The purpose of this assessment probe is to elicit students’ ideas about the transfer of matter and energy in ecosystems. The probe is designed to reveal whether students recognize that only matter is cycled through an ecosystem.
Ecosystem, cycling of matter, flow of energy
Felicia has the best answer: “I think only matter cycles through an ecosystem.” Matter and energy both move through an ecosystem. However, only matter cycles back and forth between organisms and the environment; energy moves only in one direction, with much of it being dissipated into the environment as heat. Both matter and energy can be transferred from one organism to another or from an organism to the environment; but only matter cycles within ecosystems, being used in various forms as it moves through food webs, water, soil, and the atmosphere.
The cycles in which elements or molecules move through living and nonliving components in an ecosystem are referred to as biogeochemical cycles. Examples of common elements or molecules that go through biogeochemical cycles include water, carbon, oxygen, nitrogen, phosphorus, and sulfur. The important thing to remember is that matter cycles, energy flows. Thus, an ecosystem has a constant need for energy input via photosynthetic organisms capturing the Sun’s energy.
In the elementary grades, students learn that some materials, including once-living organisms, are recycled by the earth. They know that ecosystems include living and nonliving matter and that all living things require a source of energy. They learn that the Sun is the major source of energy in most ecosystems on Earth and that all food can be traced back to plants. They can follow a food chain, from plants, to animals that eat plants, to animals that eat other animals, and to the decomposers that consume dead organisms and recycle once-living material. Understanding matter cycling at a molecular level and energy flow can wait until middle school. The water cycle is the biogeochemical cycle students learn about in elementary grades.
Middle School Students
Most of the emphasis in the middle grades is on following matter as it is transferred through food webs and into nonliving components of ecosystems. By the end of eighth grade, students should begin to link energy flow ideas to their knowledge of the cycling of matter in ecosystems. They should be able to follow the unidirectional transfer of energy as one organism eats another and know that energy does not cycle back into the ecosystem. They build on their previous knowledge of the water cycle by learning about other biogeochemical cycles, including the carbon, oxygen, and nitrogen cycles. Middle school students should also know that matter and energy are not created or destroyed as they move through an ecosystem and connect this idea to two major laws in science: the law of the conservation of mass and the law of the conservation of energy.
High School Students
High school students have sufficient knowledge of matter and energy to link these conversions to what happens in living and nonliving systems. Although there is no need to account for all the energy, students should know that most of the energy transferred from one organism to another is lost to the environment as heat and that this energy is not available for reuse. Knowledge of biogeochemical cycles is integrated across biology, chemistry, and Earth science, including the idea that some matter can remain in chemical reservoirs for a long time before it is cycled again.
This probe is most appropriate for middle and high school students. Make sure students know what a cycle is before using this probe.
K–4 Organisms and Their Environments
5–8 Populations and Ecosystems
5–8 Structure of the Earth System
9–12 The Interdependence of Organisms
9–12 Matter, Energy, and Organization in Living Systems
K–2 Interdependence of Life
3–5 Flow of Matter and Energy
6–8 Flow of Matter and Energy
9–12 Flow of Matter and Energy
American Association for the Advancement of Science (AAAS). 2001. Atlas of science literacy. Vol. 1. (See “Flow of Matter in Ecosystems” map, pp. 76–77.) Washington, DC: AAAS.
American Association for the Advancement of Science (AAAS). 2001. Atlas of science literacy. Vol. 1. (See “Flow of Energy in Ecosystems” map, pp. 78–79.) Washington, DC: AAAS.
Koba, S., with A. Tweed. 2009. Hard-to-teach biology concepts: A framework to deepen student understanding. Arlington, VA: NSTA Press.
Trautmann, N. 2003. Decay and renewal. Arlington, VA: NSTA Press.
Related Curriculum Topic Study Guides (in Keeley 2005) “Cycling of Matter in Ecosystems” “Flow of Energy Through Ecosystems”
American Association for the Advancement of Science (AAAS). 2009. Benchmarks for science literacy online. http://www.project2061.org/publications/bsl/online/index.php
Driver, R., A. Squires, P. Rushworth, and V. WoodRobinson. 1994. Making sense of secondary science: Research into children’s ideas. London: RoutledgeFalmer.
Gayford, C. 1986. Some aspects of the problems of teaching about energy in school biology. European Journal of Science Education 8 (4): 443–450.
Keeley, P. 2005. Science curriculum topic study: Bridging the gap between standards and practice. Thousand Oaks, CA: Corwin Press and Arlington, VA: NSTA Press.
Keeley, P., F. Eberle, and C. Dorsey. 2008. Uncovering student ideas in science, vol. 3: Another 25 formative assessment probes. Arlington, VA: NSTA Press.
Leach, J., R. Driver, P. Scott, and C. Wood-Robinson. 1992. Progression in conceptual understanding of ecological concepts by pupils age 5–16. Leeds, UK: University of Leeds, Centre for Studies in Science and Mathematics Education.
National Research Council (NRC). 1996. National science education standards. Washington, DC: National Academies Press.
Smith, E., and C. Anderson. 1986. Alternative student conceptions of matter cycling in ecosystems. Paper presented to the National Association of Research in Science Teaching, San Francisco, California.
Journal ArticleUsing Cogenerative Dialogues to Improve High School Students’ Internships With Scientists
Lesson PlanTalking About Forces
The purpose of this assessment probe is to elicit beginning ideas about forces. The probe is designed to reveal whether students generally identify fo...