-+How+Populations+Grow

toc =- geographic range= Geographic range- the amount of space that a population lives in, which places it is able to live in and will live in.

here is a short video of geographic range: http://www.youtube.com/watch? v=q2sC4kAKbqI&p= BD34443F5E2315FF&playnext=1& index=6

=- population density= population density- The number if individuals per unit area. it can vary tremendously depending on the species and its eco system

youtube vid: http://www.youtube.com/ watch?v=LXwEuOUIBpQ = =

=- geographic distribution= the natural arrangements of animals and __ plants __ in particular regions or districts. It can also apply to diseases or temperatures over a certain span of land mass. media type="youtube" key="7OIOnwz_w1U?fs=1" height="268" width="448"

= = This video shows the adjustments to monthly mean temperatures in the usa from 1970-2009. you only need to watch about 10 seconds to get the point of the entire video.

=- factors affecting growth rate= Growth rate: the growth rate is the rate at which something grows. “The rate of increase in size per unit time”

= =

=age structure= Age structure is the amount of organisms at a certain age and how they compare to the other ages in the population. The younger the average age of a population is the larger the population will be.

=**- Carrying Capacity** = Carrying capacity is the amount of organisms that an environment can support before logistic growth occurs.

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=- exponential growth=

Exponential Growth

 By definition exponential growth is when a population has plenty of food, space and the population is protected from predators and diseases.  The only thing that should happen under all of the circumstances in the definition shown above is an INCREASE in the population.

 Individuals who are a part of this population are always reproducing at a constant rate. A good example of exponential growth is in Bacteria like we saw in class. Bacteria reproduces every 20 minutes by splitting in half.

 Exponential growth is represented by a “J” shaped curve.

=- logistic growth=

-Logistic growth is what appears after a period of exponential growth.

-By Definition logistic growth is when a population reaches a certain capacity (carrying capacity)

-A carrying capacity is the largest number of individuals an environment can support.

Ex.) A good example of populations that use logistic growth consist of plants and animals.

- Logistic growth is represented by an "S" shaped curve.

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