Population Ecology

Population density: the number of individuals within a population per unit area

Generally, larger organisms have lower population densities because they need more resources.

High densities make it easier to find mates, but increase competition and vulnerability to predation.

Low densities make it harder to find mates, but individuals enjoy plentiful resources and space.

Reduced resources can lead to overcrowding, disease, predators, parasites, and extinction.

**Again, Balance between diversity and quality of life


Human population: 7 billion

Populations continue to rise in most countries, particularly in poverty-stricken developing nations

Although the rate of growth is slowing, we are still increasing in absolute numbers. (GR=birth, death, im/emigration)

It took all of human history to reach 1 billion: 130 years later (1930) we reached 2 billion, and added the most recent billion in 12 years. We add 80 million people each year (2.5 people/second).

Due to exponential growth, even if the growth rate remains steady, population will continue to grow. SHOW GRAPHS

At today’s 1.2% global growth rate, the population will double in 58 years (70/1.2 = 70).

If China’s rate had continued at 2.8%, it would have had 2 billion people in 2004.


Poverty and population growth are correlated

Poorer societies have higher growth rates than wealthier societies.

They have higher fertility and growth rates, with lower contraceptive use.

Poverty results in direct environmental degradation and reduced QOL

                **Rich societies don’t see the brunt of their greater environmental degradation


99% of the next billion people added will be born in poor, less-developed regions that are least able to support them.