Wednesday, September 21, 2011

Need Help!

hi. its jessie.

My muddiest point is exponential and logistical growth. Also the factors that limit population growth (density-dependent factors and desity-independed factors).

thanks!

2 comments:

  1. -Exponential growth... is when a certain species is under ideal conditions so the population increases enormously and quickly. This means they probably have enough food to support the population and there are not many predators around to eat them. This type of growth usually happens when a predator population decreases. So if you were to see a graph showing exponential growth it would probably be a high curved line going upwards.

    -Logistic growth... is usually what happens after species undergo exponential growth. In other words, it happens when the growth slows/stops after that species has reached its carrying capacity (the maximum # of individuals in an environment can support). A graph expressing this type of growth would probably be a line like in exponential growth that eventually levels off and creates somewhat of a "straight" stable line.

    -Density dependent factors are factors that affect bigger and denser populations. A good example of this is disease. The larger and denser a population is the bigger the chance an organism will catch that disease.

    -A density independent factor is basically a factor that affects a population no matter how dense or how big it is. Good examples are when a hurricane or wildfire happens. If a species only had 5 organisms in its population, a hurricane or wildfire would affect them the same way a species with a population of 500 would.

    Hope this helped(:

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  2. Bottom Line...

    EXPONENTIAL growth... population is rapidly increasing in size with no slow down in sight! Its just going up and up and up! Graph is shaped like a J.

    LOGISTIC growth... after a period a exponential growth (up and up and up!) the population levels off and stays at about the same size.

    For density dependent and independant factors... Think about a crowded classroom (very dense) vs. a less crowded classroom (not very dense).

    If there was a flu spreading, which classroom would you rather be in? The less dense one!!! Because disease is density dependent.

    BUT if there were a tornado that hit the school... which classroom would you rather be in? DOESN'T matter! Because a natural disaster is DENSITY INDEPENDANT!

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