S and J curves

S and J curves is something that we say last semester. However, we reinforced it on this semester.

S-curves

This curve, as its name says it, has a shape of an S. This is an exponential growth, but then, there is a point in which growth rate slows down when population stabilizes. This one involves density dependent limiting factors.

Furthermore, the graph involves a carrying capacity (K) which is the amount of species a system can have and maintain. The carrying capcity is asymtpotic.

The curve also shows an environmental resistance which is the area between the exponential growth curve and the s-curve. This is showed at the picture below.

J-curve

The J-curve shows a boom and bust pattern. In here population grows exponentially and then crashes. This may be called diebacks, which is when the population collapses or crashes. Furthermore, population often exceeds K before the collapse occurs, which is referred as overshift.These curves are typical from microbes, invertebrates, fish and small mammals.

References (pictures)

"Chapter 6 -- Population Dynamics ." Miami University. Department of zoology, 2002. Web. 3 Oct 2010. <http://zoology.muohio.edu/oris/Cunn06/cs6_06.htm