IB ESS HL 2.2.26 Maximum Sustainable Yield

[Maximum number: 9]

To what extent are the concepts of net productivity and natural income useful in managing the sustainable harvesting of named resources from natural ecosystems?

• understanding concepts and terminology of natural income, net productivity, natural capital, stock sustainability, replenishment, maximum sustainable yield, rates of harvest, renewable/non-renewable, goods/services, etc
• breadth in addressing and linking net productivity and natural income with sustainable harvesting, maximum sustainable yield, impacts of extraction/transport/processing, management of resources, remaining stock/capital, their applicability to abiotic/biotic resources, renewable/non-renewable resources, goods/services, etc
• examples of net productivity/natural income of named resources eg timber, freshwater, fish populations, river processing organic waste, fossil fuels, impacts of unsustainable extraction eg bycatch, access roads/infrastructure in forests, etc
• balanced analysis of the extent to which net productivity and natural income are applicable and sufficient concepts for ensuring sustainable use of a range of resources
• a conclusion that is consistent with, and supported by, analysis and examples given eg "Both concepts can be very useful in assessing the sustainability of harvesting but net productivity is more limited in its applications since it can only be applied to biotic resources and neither of the concepts take into account any unsustainable damage that may occur through the actual extraction of a resource."

The following guide for using the markbands suggests certain features that may be offered in responses. The five headings coincide with the criteria given in each of the markbands (although "ESS terminology" has been conflated with "Understanding concepts"). This guide simply provides some possible inclusions and should not be seen as requisite or comprehensive. It outlines the kind of elements to look for when deciding on the appropriate markband and the specific mark within that band.

These are possible inclusions, not required points. Assess with the official Section B, part (c) markbands below.

Marks	Level descriptor
0	The response does not reach a standard described by the descriptors below and is not relevant to the question.
1–3	The response contains: • minimal evidence of knowledge and understanding of ESS issues or concepts • fragmented knowledge statements poorly linked to the context of the question • some appropriate use of ESS terminology • no examples where required, or examples with insufficient explanation/relevance • superficial analysis that amounts to no more than a list of facts/ideas • judgments/conclusions that are vague or not supported by evidence/argument.
4–6	The response contains: • some evidence of sound knowledge and understanding of ESS issues and concepts • knowledge statements effectively linked to the context of the question • largely appropriate use of ESS terminology • some use of relevant examples where required, but with limited explanation • clear analysis that shows a degree of balance • some clear judgments/conclusions, supported by limited evidence/arguments.
7–9	The response contains: • substantial evidence of sound knowledge and understanding of ESS issues and concepts • a wide breadth of knowledge statements effectively linked with each other, and to the context of the question • consistently appropriate and precise use of ESS terminology • effective use of pertinent, well-explained examples, where required, showing some originality • thorough, well-balanced, insightful analysis • explicit judgments/conclusions that are well-supported by evidence/arguments and that include some critical reflection.

Section B, part (c) markbands (official markscheme p18)

IB ESS HL 2.2.26 Hl Maximum Sustainable Yield Questions

Exam points

IB ESS HL 2.2.26 Hl Maximum Sustainable Yield Questions question 1