Significant Ideas
Human carrying capacity is difficult to quantify.
The EF (ecological footprint) is a model that makes it possible to determine whether human populations are living within carrying capacity.
Knowledge & Understanding
Carrying capacity is the maximum number of a species, or “load”, that can be sustainably supported by a given area.
It is possible to estimate the carrying capacity of an environment for a given species; however, this is problematic in the case of human populations for a number of reasons.
An EF is the area of land and water required to support a defined human population at a given standard of living. The measure of an EF takes into account the area required to provide all the resources needed by the population, and the assimilation of all wastes.
EF is a model used to estimate the demands that human populations place on the environment.
EFs may vary significantly by country and by individual and include aspects such as lifestyle choices (EVS), productivity of food production systems, land use and industry. If the EF of a human population is greater than the land area available to it, this indicates that the population is unsustainable and exceeds the carrying capacity of that area.
Degradation of the environment, together with the consumption of finite resources, is expected to limit human population growth.
If human populations do not live sustainably, they will exceed carrying capacity and risk collapse.
Applications & Skills
Evaluate the application of carrying capacity to local and global human populations.
Compare and contrast the differences in the EF of two countries.
Evaluate how EVSs impact the EFs of individuals or populations.
Guidance
Discussion of the application of the carrying capacity that allows human populations to grow beyond the boundaries set by their local resources should include:
the range of resources used
human ingenuity, meaning that humans are able to substitute one material for another
variations in lifestyles
importation of resources
technological developments that give rise to continual changes in the resources required and that are available for consumption.
Because carrying capacity for human populations is difficult to calculate, it is also difficult to estimate the extent to which they are approaching or exceeding carrying capacity, although environmental indicators (see sub-topic 1.4) may help in this respect.
The EF is a model that provides a way round this dilemma. Instead of focusing on a given environment and trying to calculate the carrying capacity it provides, it focuses on a given population (with its current rate of resource consumption) and estimates the area of environment necessary to sustainably support that particular population. The size of this area is compared with the area available to the population, then gives an indication of whether the population is living sustainably and within the carrying capacity provided.
Key Vocabulary
HERE
Textbook Reading and/or Activities
Pages 55-59, 154-172
Case Study (p.158-159)
Exercises (p.159)
Case Studies (p.165-166)
Case Study (p.169)
Case Study (p.170-171)
Exercises (p.173)
Case Study (p.306-307)
Notes
i-Biology Notes (Not available)
A detailed set of notes, created by Stephen Taylor, examining U1 - U8 and A1 - A4.
i-Biology Study Questions (Not available)
A series of questions, created by Stephen Taylor, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
Bioknowledgy Notes (Not available)
A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
Bioknowledgy Study Questions (Not available)
A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
Learning Activities
Reducing AISB's Ecological Footprint
This activity challenges students to examine the ecological footprint of the school and determine what would be the best strategy to go about reducing it (K&U 7 and A&S 3).
Supplemental Reading
This video outlines concepts K&U 1-2 and A&S 1.
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