The word energy is used every day by students in expressions like, ‘I have run out of energy’ or ‘I need some more energy’. Students’ everyday use of this term can often cause confusion for students when learning to use the correct scientific term. Most students recognise that almost all organisms need a source of energy to survive, function and reproduce. Students are strongly influenced in this area of science by the media and their everyday experiences. Show
Students often have trouble interpreting food chains, particularly where the diagram uses arrows to represent energy exchange. Students may see the arrows as referring to a flow of matter (stuff) up a food chain. This is a problem as matter is recycled in an ecosystem but energy is not. Students also have a limited understanding of sources of energy in marine ecosystems, basing most of their understanding on their experiences of land ecosystems. Students are often very egocentric, and believe that all organisms exist solely for the benefit (or annoyance) of humans. For example, students cannot suggest a useful purpose for mosquitoes or spiders. Research: Driver, Squires, Rushworth & Wood-Robinson (1994) There is also a widely held conception by students that energy accumulates as one moves up through a food chain and therefore the top predator would have accrued all of the energy from the producers and the other consumers lower down in the food chain. Students are confused about where plants get their food from and will often believe that it comes from the environment (mainly from the soil and water) rather than from plants manufacturing it themselves. This is because many students have had gardening experiences that involve watering and adding nutrients (fertilizer) to the soil. Students are usually aware that plants use carbon dioxide but are often unsure why and are confused about its involvement in the weight increase of a plant and manufacture of food. Research: Driver, Squires, Rushworth & Wood-Robinson (1994) Scientific viewEnergy is transferred between organisms in food webs from producers to consumers. The energy is used by organisms to carry out complex tasks. Critical teaching ideas
It is important that students are assisted to develop an understanding of the scientific terms ‘food’ and ‘nutrients’ and explore their relationship to energy and matter . The term ‘energy’ as used when working with food webs is identical to the energy that is discussed in other domains of science. A key idea to develop is that energy progresses through the food web (or food chain) from its source, the sun, undergoing repeated transformations. It is also critical to develop the idea that a food web can be complex and is made up of a number of interrelated food chains. Teaching activitiesPractise using and build the perceived usefulness of a scientific model or ideaStudents should be encouraged to observe and discuss examples of food chains where energy is transformed and matter conserved. Consider undertaking activities that help students to develop an understanding of the source of the vast majority of energy in all ecosystems and the energy transformations that take place as it progresses through the food web. Students could also undertake a number of activities that concentrate on identifying the transformations that energy must undergo as it progresses through an ecosystem. One approach is for students to investigate the interactive ‘food webs’ website at the following link:
While attempting the tasks students can gain experience at identifying the likely positions that different organisms will have in the food webs they explore. As a follow up task, ask students to cut out pictures of organisms from magazines that are likely to be connected in the same food web or locate images on the internet (or school intranet) for them to construct a PowerPoint or Inspiration food web display. Ask students to identify and discuss the features of their food webs that have been simplified when comparing them to situations that may exist in the real world. Promote reflection on and clarification of existing ideasStudents could examine a food web where organisms are threatened, removed or die. They could then track how the energy transformations are altered in the food chain (or food web). They can also track how sources of energy for others are changed. Further resourcesScience related interactive learning objects can be found on the FUSE Teacher Resources page. To access the interactive learning object below, teachers must login to FUSE and search by Learning Resource ID: Which statement is most true about energy and nutrients in ecosystems?The correct answer is option b because nutrients cycle through the ecosystem and energy flows one way.
Which is correct about energy flow in ecosystem?That's why the flow of energy in an ecosystem is described as the direction of energy from the sun to the producer and then to the next level of the pyramid of energy. That's why flow of energy in the ecosystem is unidirectional in nature. Hence, the correct answer is option (A).
How is energy described in an ecosystem?The energy flow takes place via the food chain and food web. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis.
What is true about energy and materials in an ecosystem?In ecosystems, both matter and energy are conserved. Energy flows through the system—usually from light to heat—while matter is recycled.
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