APES Unit 3

K-selected species

• low growth rate

• high survivability

• Type 1 and 2 growth

r- selected species

• high growth rate

• low survivability

• Type 3 growth

Type 1 survivorship

• low early death rate

• K-selected

• high parental care

• ex: humans, elephants

Type 2 survivorship

• circumstantial

• constant death rate

• ex: birds, rodents, lizards

Type 3 survivorship

• high death rate early in life

• low parental care

• r-selected

• fish, insects, frogs

carrying capacity (K)

the size of a population that the available resources can sustain indefinitely

carrying capacity graph

1. area pop increases

2. overshoots K

3. food becomes limiting/K falls

4. pop stabilizes @ new K

5. drought occurs, K drops

6. drought breaks, K stabilizes up, but lower than initially

total fertility rate (TFR)

average # children born to a woman during her life

factors affecting TFR

Medical care

Jobs for women

Death (infant)

Literacy in women

Labor (need for child labor)

Birth control access

“Moms Just Don’t Like Labor & Birth”

replacement level fertility

average # kids a couple must have to replace themselves

2.1 currently

Infant Mortality Rate (IMR)

# babies per 1000 who pass before 1st birthday

Factors influencing pop dynamics

• birth/death rates

• fertility

• life expectancy

• immigration/emigration

• family planning

population density

total pop/total area

pop doubling time

70 / % growth rate

growth rate (r)

• % birth rate - % death rate

• [(total in) - (total out) / total pop] x 100

• CBR-CDR/10

Malthusian theory

human pop is growing exponentially while food grows linearly

→ demand for resources will soon surpass supply

density dependent limiting factors

more resources = more pop growth

ex: predation, disease, parasitism

density independent limiting factors

conditions that affect the size and growth rate of a pop regardless of how crowded or dense it is; abiotic

-→ natural disasters, human activities

biotic potential

the maximum rate a pop can increase when conditions are ideal

logistic growth

when pop growth rate slows down as size approaches max limit imposed by scarce resources

Stage 1 age structure

• slow growth

• high birth, high death

• short life expectancy

• kids in workforce

Stage 2 age structure

• rapid growth

• high birth, low death

• no fam planning

stage 3 age structure diagram

• stable growth

• low birth, low death

• more access to birth control

• educated women

stage 5 structure diagram

• declining growth

• death > birth

• deaths happen later

demographic transition

• the transition from higher to lower birth/death rates as development occurs

% change

(new-old) / old x 100

population change

(# births + immigrants) - (# deaths + emigrants)

pre industrial

• poor medical care

• unreliable access to food/water

• low access to birth control

transitional

• industrialization starts

• improved medical care & food production

• little fam plannning

industrial

• increased job opportunities

• increasing access to education

• increased access to birth control

post-industrial

• aging pop

• high pop

• rising unemployment (retiring)