David Suzuki argues that in any discusson of population, we must recognize the principle of exponential growth (when the growth rate of the value of a mathematical fuction is proportional to the function's current value). To illustrate the impact of exponential population growth, Suzuki uses the analogy of baterial growth in a test tube. The test tube represents the planet and its food supply; the bateria, human population; the growth rate such that the test tube will be full in 60 minutes. At 55 minutes, the test tube is only 3% full; at 59 minutes it is half full. According to Suzuki we are at the 59 minute mark. The lessons to be learned from the analogy the capacity of the biosphere like the test tube is fixed/ finite

the soluton is not to be found in other test tubes -planets

growth cannot be equated with progress

Recommendation of how and where to use it The video serves as a useful introduction to the Malthusian theory that argues that because population increases exponentially and food/resources grow arithmetically, population size will ultimately exceed the ability to support itself. Suzuki's use of the growth of bateria in a test tube is a dramatic illustration of this theory. Once students have been introduced to the Malthusian/Suzuki thesis, they may be required to investigate the arguments made by those that have challenged this thesis. Any discussion of sustainable development, carrying capacity, resource exploitation should include consideration of current and future population growth. The issue has relevance for a number of subject areas. History - the collapse of a number of historical societies such as Easter Island has been linked to population growth that degraded and destroyed the local resource base.

Geography - units of study that focus on human-environmental interaction or resource management include consideration of the impact of population growth.

Economics - those who challenge the practice of measuring economic growth by reference to GNP suggest that such a measurement fails to consider the ability of the resource base to sustain growing population and growing consumpton. The connection between socio-economic factors and birth rates is also essential for an understanding of populaton patterns.

Environmental Science- units on ecological footprints at the national and international level require reference to the respective population pressures

Math - the debate over population trends and their possible impact requires an analysis of the data available and its implications for sustainable development