formulas to know for APES test

Rule of 10% Formula

Approximately 10% of the energy is transferred from one trophic level to the next in an energy pyramid.

Rule of 70: Doubling Time

70 / Growth Rate (as a percentage)

NPP formula

NPP = GPP - R

Percent Change Formula

{(Final - Initial) / Initial} \times 100

(new-original)/original\cdot100

Population Density Formula

Population / Area

Population Change Formula

(Births + Immigration) - (Deaths + Emigration)

Power Formula

Energy (or Work) / Time

Watts (W)

The unit of Power

Energy Formula

Power x Time

Half-Life Fraction Remaining

{(1/2)^t}

Watt-Hours (Wh)

A unit of Energy

GPP formula

GPP = NPP + R