APES ( AP ENVIRONMENTAL SCIENCE) UNIT 3

Specialists vs. Generalists

specialists- use only a few types of food, live in few places

generalists- using most food types, live anywhere

K-selected species characteristics

•Long development, long lived

•Live near carrying capacity

•Slow reproduction

•Few offspring, but high investment

r-selected species characteristics

- small size

- fast paced life

- large # offspring

- limited parental care

biotic potential

Maximum rate at which the population of a given species can increase when there are no limits on its rate of growth.

age cohort

an aggregate group of people born during the same time period

survivorship curve

Graph showing the number of survivors in different age groups for a particular species.

type 1 curve of survivorship

Most survive while young, die off quickly when they are older (Ex. Humans)

Type 2 Curve (Survivorship)

Equal survivorships (Ex. rodents)

Type 3 Curve (Survivorship)

Most die when young, then they survive a long time (Ex. fish)

K-selected species

type 1 survivorship curve - long lifespan

r-selected species

type 3 survivorship curve- short lifespan

Carrying capacity refers to

the maximum number of individuals that can be supported by an ecosystem

Overshoot

when a population becomes larger than the environment's carrying capacity

Dieback

a sudden decline in population

limiting resource

A short supply of resources restricting the growth of a population (Ex. food, shelter, water)

mortality

death

Fucundity

fertility

rapid growth

when population grows quickly

negative growth

the actual decline in population due to less than replacement births or extensive diseases

population momentum

continued population growth that does not slow in response to growth reduction measures

3 factors that influence TFR

educational opportunities for females, access to family planning, gov. acts and policies

replacement-level fertility rate

average number of children a couple must have to replace themselves (2.1)

infant mortality rate

The percentage of children who die before their first birthday within a particular area or country.

CBR (Crude Birth Rate)

The total number of live births in a year for every 1,000 people alive in the society.

CDR (Crude Death Rate)

The total number of deaths in a year for every 1000 people alive in the society.

density dependent

disease, competition, predation

density independent

temperature, natural disasters

Rule of 70 formula

number of years to double = 70/growth rate

theory of demographic transition

the theory that as a country moves from a subsistence economy to industrialization and increased affluence it undergoes a predictable shift in population growth

pre-industrial stage

birth and death rates high, population grows slowly, infant mortality high

transitional stage

death rate lower, better health care, population grows fast

post-industrial stage

low birth and death rates

characteristics of a developed country

more money, low birth rates, more sanitation, more health care, lower death rates

characteristics of a developing country

Poor, struggling economies which lack diversity, lack of technology, poor schooling, limited access to healthcare.

exponential growth model

a mathematical description of idealized, unregulated population growth, not limited by resources (j-curve)

logistic growth model

a mathematical description of idealized population growth that is restricted by limiting factors (s-curve)

population age structure

how many individuals fit into age categories. Shown by age structure diagrams

growth rate equation

(CBR-CDR)/10

Total Fertility Rate (TFR)

an estimate of the average number of children that each woman in a population will bear throughout her childbearing years