Which pair constitutes only the immediate effects of earthquakes?

Exponential growth (unlimited resources):

where $N$ = population size, $r$ = intrinsic rate of increase (per capita growth rate).
Graph: J-shaped curve.

Logistic growth (limited resources):

where $K$ = carrying capacity (maximum population size environment supports).
Graph: S-shaped (sigmoid) curve.

Density-independent factors (abiotic, affect all individuals equally regardless of population density): droughts, floods, temperature extremes.
Density-dependent factors (biotic/abundance effects, intensify with higher density): emigration (often due to overcrowding/competition).

Options (from image):
A. Droughts
B. Floods
C. Emigration
D. Temperature (or similar abiotic).

Answer: C

C

Density-dependent: competition, predation, disease, emigration (rate increases with $N$).
Per capita growth rate $\frac{1}{N} \frac{dN}{dt}$ decreases as $N \to K$.
Density-independent: weather events, affect $\frac{dN}{dt}$ independent of $N$.

Exponential: straight line on semi-log plot, accelerating increase.
Logistic: initial exponential, then levels at $K$.

Exponential graph: J-shape
Logistic graph: S-shape

From logistic equation, equilibrium when $\frac{dN}{dt} = 0$: $N = K$.
Graph: horizontal asymptote.

K