Roy 2.1

Front 1

-Explain  the  difference  between  geometric  and exponential  growth  using   examples  from  natural  populations.

Back 1

-Geometric Growth: If a population reproduces in synchrony at regular time intervals (reproduce at the same time, then die), then geometric growth occurs.
Nt+1=Nt(Lambda) or Nt = No*(Lambda)^t (lambda=geometric growth rate)

-Exponential Growth: Individuals that reproduce continuously and have overlapping generations, experience exponential growth. (non-synchrony)
Nt+1 = No*e^r*Nt or dN/dt = r*N (r = intrinsic rate of growth)
-lambda = e^r ; r = ln(lambda)
-ex:/ reindeer, humans (exponential) annuals - dandilions, salmon (geometric)

Front 2

-Explain  why  the  geometric  and exponential  growth  curves  overlap.

Back 2

-They overlap because the equations are similar in form except that lambda = e^r

Front 3

-Give  examples  of  factors  that  limit and  factors  that  regulate population  growth  
and  how  they  do  so.

Back 3

-Density dependent factors regulate a population with an upper and lower bound
-ex:/ intrinsic rate of growth increases when population size is low and decreases when population size is high.

-Density independent factors limit a population with an upper bound but no lower bound.


-ex:/ disturbances are often density independent - A disturbance often stops growth (upper bound) but there is the possibility of extinction depending on severity of disturbance (no lower bound)

Front 4

-Explain  how  a  resource and  a  physical  factor  differ.

Back 4

-Resource: essential for survival, non-substitutable and depletable. Ex:/ oxygen, nutrients esc.

-Physical Factor: Something that effects growth but are not consumed or depleted Ex:/ temperature, salinity, wind esc.

Front 5

-Explain  how  population  size  may  be  influenced  by  density‐dependent, density‐ independent ,  and  inversely  density‐dependent  factors.

Back 5

-Density Dependent: When a factor has a negative relationship with respect to population size. Ex:/ intrinsic rate of growth, br , death rates, esc

-Density Independent: When a factor does not change with respect to population size. Ex:/ periodic disturbances such as floods, fires

-Inversely Density Dependent: When a factor has a positive relationship with respect to population size. Ex:/ Mutualism : A situation where one species benefits from the presence or action of another.

Front 6

-Explain  why  the  Allee effect  slows  down  the  recovery  of  nearly  extinct   populations.

Back 6

-Allee Effect: Population growth rate decreases as population density decreases

-This happens because individuals have difficulty finding mates at low densities.