APES Math Formulas

all ap environmental science math formulas

what is population density?

population / area

what is the rule of 70?

70 / growth rate %

what is population growth rate (%)?

[(births - deaths) / (immigrants - emigrants)] x 100

denominator can also just be “# of people”

what is rate of change?

(new- old) / new time - old time [basically just AROC]

what is percent change?

[(old - new) / old] x 100

what is the 10% rule?

states that only 10% of energy moves up the trophic level

what is net primary productivity (NPP)?

gross primary productivity - respiration

what is gross primary productivity (GPP)?

rate of photosynthesis by plants

what is fuel efficiency?

distance traveled / unit of fuel consumed

what is dimensional analysis?

quantity1 * conversion factor/quantity2 = result

what is half life?

A = Pe^rt or t_1/2 = ln(2)/x

what is LD₅₀?

Dose/Weight

the bigger the dose, the safer the chemical

what is lethal dose?

mass x LD₅₀