19.2: population growth

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