19.2: POPULATION GROWTH
1. MODELS OF GROWTHExponential
a) birth and death rates are constant (b > d)
1. MODELS OF GROWTHExponential
a) birth and death rates are constant (b > d)b) the rate increases as the population
gets largerc) limited by density-independent factors
DRAW THIS GRAPH AND A LINE SHOWING WHAT A LOGISTIC GROWTH WOULD LOOK LIKE
works well for bacteria growth but not for most organisms
1. MODELS OF GROWTHLogistic
a) starts off as b> db) levels off as it reaches carrying
capacity (K)
1. MODELS OF GROWTHLogistic
a) starts off as b> db) levels off as it reaches carrying
capacity (K)a) (K): the number of individuals the
environment can support over time.
1. MODELS OF GROWTHLogistic
a) starts off as b> db) levels off as it reaches carrying capacity
(K)a) (K): the number of individuals the environment
can support over time.
c) This is when b rates = d rates (zero population growth)
d) limited by density-dependent factors
DRAW THIS GRAPH AND A LINE SHOWING WHAT A LOGISTIC GROWTH WOULD LOOK LIKE
Label carrying capacity with a K
Most organisms such as seals, and whales follow this model
2. REGULATING POPULATION GROWTHLimiting factors: restrains population growth
2. REGULATING POPULATION GROWTHLimiting factors: restrains population growthDensity-independent factors: no regard for population density
EX. Weather, seasons, natural disasters
2. REGULATING POPULATION GROWTHDensity-dependent factors: increase
or become more prominent when the population density increases
EX. predation, pollution, food shortage
3. GROWTH RATE Growth rate= births – deaths per capita
GROWTH RATE PRACTICE 37 births/300 mice on one month; 20 deaths/ 300 mice per month.
GROWTH RATE PRACTICE 37 births/300 mice on one month; 20 deaths/ 300 mice per month.
Growth rate = 37-20 = .057 per month 300
GROWTH RATE PRACTICE 100 deaths and 1000 births in a cricket population of 2,000 in 6 months.
GROWTH RATE PRACTICE 100 deaths and 1000 births in a cricket population of 2,000 in 6 months.
Growth rate = 1000 -100 = .45 every six months 2000
GROWTH RATE PRACTICE 25 births/200 guppies in one week; 75 deaths/ 200 guppies per week.
GROWTH RATE PRACTICE 25 births/200 guppies in one week; 75 deaths/ 200 guppies per week.
Growth Rate= 25-75 = -.25 per week
200
CLASS WORKOceanic Bacteria Lab