3.7 Limits to Growth Explain the difficulties in applying the concept of carrying capacity to local human populations. Explain how absolute reductions in energy and material use, reuse and recycling can affect human carrying capacity. Spec points: 3.6.1 – 3.6.2

Explain the difficulties in applying the concept of carrying capacity to local human populations. RECAP: Define ‘carrying capacity’. Why might a species’ population move closer towards its carrying capacity?

Carrying Capacity “The maximum population size of a species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment.” Ways humans move closer to carrying capacity Growth in population size Reduction in resources required by that species Increasing inefficiency / waste in consumption

In animal systems, there are limited factors that affect a populations ability to reach or exceed its carrying capacity for extended amounts of time. As with the Hare / Lynx examples, if the Lynx exceeds its carrying capacity for that area (not enough Hare/food to go around) then the population declines beneath the carrying capacity again). How might humans artificially alter their own resource systems to avoid reaching their carrying capacity?

Use the images below to help identify why ‘carrying capacity’ is difficult to apply to human populations. Explain the significance of each image, stating why these issues make the carry capacity difficult to apply to humans.

Why is ‘carrying capacity’ difficult to apply to human populations. Humans are not limited to resources in one location or area, due to import / export and also our ability to move around to where resources are available. We can make use of a huge range of resources, not a limited number. We can use technology to find alternatives to meet our needs. We can use technology to make our consumption of resources more efficient. Humans have different resource needs depending upon their location, culture, level of development etc… For each of the above reasons, name and elaborate upon a specific example you know.

Draw a sketch graph to show Malthus and Boserup’s views on the relationship between population size and resource use over time. Resource Availability Population Time

Explain how absolute reductions in energy and material use, reuse and recycling can affect human carrying capacity. The human ‘carrying capacity’ is largely affected by these 3 variables.

Resource Consumption Using examples we have already studied, explain how the following would affect human carrying capacity: Increase / decrease in energy use? Change to alternative energy sources? Increase / decrease in material resource consumption? Change to alternative material resources? Re-use of material resources? Recycling of material resources? Write a few lines for each scenario, referring to named examples, perhaps using data, and clearly explaining the impact this would have on carrying capacity.