Populations and Population Growth NOTES February 07, 2012

Populations and Population Growth

Populations and Population Growth NOTES February 07, 2012

Human Population Clocks

http://www.ibiblio.org/lunarbin/worldpop

http://galen.metapath.org/popclk.html

These "clocks" can be found all over the internet.

Populations and Population Growth NOTES February 07, 2012

Population- a group of the same species of organism living in an area.

Populations have some really cool names.

A pod of bottlenose dolphins

Others?

http://en.wikipedia.org/wiki/List_of_animal_names

Populations and Population Growth NOTES February 07, 2012

Population Growth

* Under the right conditions, organisms produce many more offspring than it takes to replace themselves.

i.e. birth rate > death rate

*If reproduction was unchecked, any species could grow to fill the entire ocean.

Why doesn't this happen?

Populations and Population Growth NOTES February 07, 2012

Populations grow and eventually reach a:

Carrying Capacity- the largest population that can be sustained.

Populations and Population Growth NOTES February 07, 2012

Human Carrying Capacity?If you assumed that every possible square kilometer of Earth's arable land was farmed to maximum efficiency and we all crammed together in huge cities, we could have support as many as 30 billion people - 5 times as many as are living now - or more. http://library.thinkquest.org/C003763/index.php?page=terraform03

What is the carrying capacity of Earth for humans? This question has been asked for more than 300 years by scientists interested in demography. The first known estimate for the carrying capacity of Earth was made by Anton van Leeuwenhoek in 1679. Since then, the estimates of carrying capacity have varied from less than 1 billion to over 1,000 billion (a trillion people). The average of the various estimates is around 10-15 billion. Why should these estimates of carrying capacity be so variable?

Carrying capacity is difficult to estimate, and the scientists who produce these estimates use different methods to get their answers. Some researchers use curves like that produced by the logistic equation to predict the future maximum of the human population. Others generalize from existing "maximum" population density and multiply this by the area of land that could be inhabited. Still other estimates are based on a single assumed population constraint such as food. Basing carrying capacity on food as the limiting factor is one promising approach. However, such estimates are limited by the assumptions required about the amount of available farmland, the average yield of crops, the prevalent diet (vegetarian or meat eating), and the number of calories to be provided to each person each day.www.biog1105-1106.org/demos/106/.../16.carryingcapacity.pdf