Population Growth

CHAPTER 11:  POPULATION GROWTH

***The following notes are taken directly from –Population Growth Chapter 11 of  Ecology:  Concepts and Applications, 5th edition, by Manuel C. Molles Jr.***

*Given suitable environmental conditions, aquatic and terrestrial populations will manifest their great capacity for growth.

*Sizes of populations fluctuate in terrestrial, as well as aquatic environments.

*In the presence of abundant resources, populations can grow at geometric or exponential rates.

*Geometric population growth is growth by any population.

*Exponential population growth is growth by a population in which the reproduction is nonpulsed, and a continual process.n with pulsed reproduction; successive generations differing in size by a constant ratio.

*The per capita rate of increase attained by a species under ideal environmental conditions–where birth rates, death rates, and age structure are constant is called the intrinsic rate of increase.

*As resources are depleted, populaton growth rate slows and eventually stops; this is known as logistic population growth.

*The environment limits population growth by changing birth and death rates.

*Biotic factors which effect population density are called density-dependent factors. –Examples include desease and predation.

*Abiotic factors can exert their influences independently of populatoin density and so are called density-independent factors.  –Examples include flooding and extreme weather conditions.

*Most of the significant environmental problems on earth today trace their origins to the effects of the human population on the environment.

*The human species is virtually everywhere on the planet; we occupy every continent.

*Within continents, human populations attain their highest densities in eastern, southeastern, and southern Asia.

*In 2008, 60.6% of the global population, or about 4 billion people, were concentrated in Asia.

*While the populatoins of many developed countries are either stable or declining, those of most developing countries are growing, and the trend for the entire global populatoin is continued growth.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s