AP ENVI SCI UNIT 3

specialist species

• dont tolerate changing ecosystems very well

• narrow ecological tolerance

• specific food requirements

• specific environmental conditions

• giant panda, osprey, mountain gorillas

what species thrives in constant habitats?

specialist

generalist species

• large range of tolerance

• more likely to be invasive

• broad range of resources

• mule deer, raccoons, bald eagles, rats

generalist species can thrive in

advantaged in habitats that are changing

k-selected species

• large

• few offspring

• few reproduction events

• expend significant energy for each offspring

• reproduce more than once in their lifetime

• live in stable environments

• tend to be specialist

r-selected species

• small

• too many offsprings

• expend minimal energy for each offspring

• mature early

• short life spans

• reproduce only once in their lifeitme

• can thrive in disturbed environments

• tend to be generalist

competition for k

high

competition for r

low

survivorship curve

x axis - life span

y axis - percent orgs surviving

Type 1 curve

aka late curve

• large % of population survives

• the highest curve

• survives because parents take care of the young

type 2 curve

aka constant loss

• death rate contant

• stright diagonal line through the middle

type 3 curve

aka early loss

• the bottom curve

• large % of pop died early

carrying capacity [K]

maximum number of organisms the environment can support without degration of resources

biotic potential

max reproductive rate under ideal conditions

what happens if pop exceeds K

• OVERSHOOT

• DIEBACK

why can dieback can be catastrophic

• no natural predators

• limited resources left

• unable to grow back

what type of species have a rapid groeth rate and exceed carrying capacity quickly

r selected

what happens when population exceed K

RESOURCE DEPLETION

is K constant?

no it depends on the available resources

what results in a population die back?

1. famine

2. disease

3. conflict

why can overshoot occur?

due to lag time.

resources remain high while disease and competition increase death rate

biotic potential

maximum reproductice rate under the right conditions

density dependent resistant factors

• biotic

• have a strong influence when number of organisms in an area reaches a certain limit

• predation

• paratism/disease

• competition for resources

density independent resistant factors

• abiotic

• have an affect on all populations regardless of size or density

• natural disasters

• drought

exponential growth

• unlimited resources

• all populations will experience exp growth

logistic growth

limited resources

when it hits the carrying capacity competition for resources becomes a density dependent factor

fecundity

ability to produce offsring

all reproductive strategy togetehr

age structure diagram

population pyramids

x axis - male or female

y axis - age group

lower group → pre reproductive

middle group → reproductive

top group → post reproductive

bottom heavy pyramid

growing population

→ indicator of a developing nation

india, brazil, nigeria, mexico

middle heavy

stable population

→ nation more developed and well-off

USA, Austrailia, Canada, Sweden

top heavy

declining population

→economically socially developed

→ education common

japan, russia, germany, italy

total fertility rate TFR

average number of children a woman will have in her childbearing years [15-49]

meant to show average rate

developing nations TFR

over 2.1

can be as high as 6 or 7

developed nations TFR

below 2.1

the lower the TFR the slower the growth

TFR factors

age of frist preganancy

educational oppurtunities

family planning

healthcare

government policies

factors leadingg to drop in TFR

1. education

2. family planning

3. less need for children in the workforce

4. government can limit thriugh incentives

5. cost of raising children increases

common factors on human population

1. birth rate

2. death rate

3. education

4. infant mortality

5. age of marriage

6. nutrition

birth rate

high → speed rate

low → slow it down

death rate

high → slow growth

low → speeds

infant mortality

high → slow

low speed

nutrition

high → speeds

low → slows

education of women

high → slow

low → speeds

age of marriage

early → speeds

later → slows

limitations on human population

all populations have a carrying capacity [malthus]

density independent factors → affect everyone the same [heat, drought, storms, fires]

density depedent factors → dependent on number [disease, territory size, food vailibilty, access to clean air and water]

storms affecting human populations

high density counties had a drop in population

population had too much damage to their homes → leading to the population moving away.

doubling time

the amount of time for a population to double at a constant growth rate

doubling time is calculated using rule of 70

doubling time formula

70/r

r → growth rate of a population

r needs to be a perceNTAGE NOT A DECIMAL

demographic transition shows trends in

1. birth rate

2. death rate

3. total population

general demographic transition

tend to move from agriculture to industrial

in stages 1-2/phase 1 → higher infant mortality, children are needed in the workforce → zero growth [pre industrial phase]

stages 3-4 →

phase 1

pre industrial phase

low 0 growth

children in workforse, high infant mortality

phase 2

improved medicine, sanitation, food.

very high growth

transitional

phase 3

high education, low infant mortality

slow growth

industrial

phase 4

high education, low inf mortality, older popos may become a tax burden

0 to negative growth

post-industrial