Density-dependent factors affect population size in relation to the population’s density.

Density-dependent factors down into two categories. 

Negative density dependence 

Positive density dependence (inverse density dependence

TLS Online TPP Program

#Id: 1813

#XL - T Zoology

Population sizes at various times

N_t = N₀e^rt

TLS Online TPP Program

#Id: 1814

#XL - T Zoology

Per capita rate of increase, r, related to the net reproductive rate, R₀

TLS Online TPP Program

#Id: 1815

#XL - T Zoology

TLS Online TPP Program

#Id: 1816

#XL - T Zoology

r, is affected by organismal size and generation time.

TLS Online TPP Program

#Id: 1817

#XL - T Zoology

When conditions are optimal for the population, r is at its maximum rate and is called the intrinsic rate of increase (_rmax).

TLS Online TPP Program

#Id: 1818

#XL - T Zoology

r<0, the population decreases

r=0, the population remains constant

r>0, the population increases