B.3.4.- population ecology

What are two types of growth curves seen in populations?

1. S-curve (logistic)

2. J-curve (exponential)

Contrast S and J curves

S-Curve: occurs when a population reaches its carrying capacity in environment that can only contain the carrying capacity. They will be seen in any stable population that occupies a fixed space. (k-strategist)

J-Curve: Ideal environment where resources are unlimited for organisms at the time. Seen when animals are conserved or in species with short life spans where growth exceeds deaths. (r-strategists)

Contrast the two reproductive methods.

K-selection (S-curve): organisms live in a stable environment and exist close to the carrying capacity. Organisms exhibit traits duch as slow reproduction, large size. few offsprings and long lifespans.

r-strategists (J-curve): organisms live in unstable environment. They show traits such as small sizes, short lifespan, many offsprings and fast reproduction.

what is the formula for population change? and pop change %?

population change = (b-d) + (i-e)

births

deaths

immigration

emigration

% = pop change/initial pop x 100