Option C: Communities and ecosystems
Understandings:
• Most species occupy different trophic levels in multiple food chains.
• A food web shows all the possible food chains in a community.
• The percentage of ingested energy converted to biomass is dependent on the respiration rate.
• The type of stable ecosystem that will emerge in an area is predictable based on climate.
• In closed ecosystems energy but not matter is exchanged with the surroundings.
• Disturbance influences the structure and rate of change within ecosystems.
• Most species occupy different trophic levels in multiple food chains.
• A food web shows all the possible food chains in a community.
• The percentage of ingested energy converted to biomass is dependent on the respiration rate.
• The type of stable ecosystem that will emerge in an area is predictable based on climate.
• In closed ecosystems energy but not matter is exchanged with the surroundings.
• Disturbance influences the structure and rate of change within ecosystems.
Applications and skills:
• Application: Conversion ratio in sustainable food production practices.
Utilization:
• Poikilotherms (animals that have a variable body temperature) are more effective producers of protein than homeotherms (animals that maintain a
regulated body temperature) as they have a higher rate of conversion of food to biomass.
• Application: Conversion ratio in sustainable food production practices.
Utilization:
• Poikilotherms (animals that have a variable body temperature) are more effective producers of protein than homeotherms (animals that maintain a
regulated body temperature) as they have a higher rate of conversion of food to biomass.
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Application: Consideration of one example of how humans interfere with nutrient cycling.
Skill: Investigation into the effect of an environmental disturbance on an ecosystem.
Examples of aspects to investigate in the ecosystem could be species diversity, nutrient cycling, water movement, erosion, leaf area index, among
others.
Examples of aspects to investigate in the ecosystem could be species diversity, nutrient cycling, water movement, erosion, leaf area index, among
others.
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Skill: Analysis of a climatograph showing the relationship between temperature, rainfall and the type of ecosystem.
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Skill: Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest.
Theory of knowledge:
Do the entities in scientists’ models, for example trophic levels or Gersmehl diagrams, actually exist, or are they primarily useful inventions for predicting
and explaining the natural world?
Theory of knowledge:
Do the entities in scientists’ models, for example trophic levels or Gersmehl diagrams, actually exist, or are they primarily useful inventions for predicting
and explaining the natural world?
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Skill: Comparison of pyramids of energy from different ecosystems.
It is so because at each transfer about 80 - 90% of the energy available at lower trophic level is used up to overcome its entropy and to perform metabolic activities. Only 10% of the energy is available to the next trophic level (as per Lindemann's ten percent rule).
It is so because at each transfer about 80 - 90% of the energy available at lower trophic level is used up to overcome its entropy and to perform metabolic activities. Only 10% of the energy is available to the next trophic level (as per Lindemann's ten percent rule).
