Population Test- Environmental Science

Population dynamics

Study of how populations change in size, density, and age distribution

Density dispersal patterns in nature

Clumped, even/uniform and random

Population change equation

(Births + immigration) - (deaths + emigration)

Age structure

A populations age structure can have a strong effect on how rapidly its size increases and decreases.

Histogram age distribution

Under 15, Ages 15-44, ages 45+

Survivorship curves

Type 1 Late loss- species can expect to live long lives

Type 2 Constant Loss- an equal chance if dying throughout life

Type 3 Early Loss- species mostly die young

Environmental resistance decrease factors

Too much or too little light, light temperature too high or low, unfavorable chemical environment, low reproductive rate, specialized niche, inadequate food supply, poor habitat, too many competitors, inadequate defense from predators, diseases and parasites, inability to migrate or adapt to change

K-Carrying Capacity

The maximum # of individuals of a given species that can be sustained indefinitely in a given amount of space

K-selected species

•Elephant & saguaro cactus

•Fewer, larger off spring

•High parental control and protection of offspring

•Later reproductive age

•most offspring survive to reproductive age

•larger adults

•adapted to stable climate and environmental conditions

•lower population growth rate (r)

•population size fairly stable and usually close to carrying capacity (k)

•specialist niche

•high ability to compete

•late successional species

R-intrinsic rate of increase

The rate at which a population would grow if it had unlimited resources

R-selected species

•Cockroach & dandelion

•many small offspring

•little or no parental and protection of offspring

•early reproductive age

•most offspring die before reaching reproductive age

•small adults

•adapted to unstable climate and environmental conditions

•high population growth rate (r)

•population size fluctuates wildly above and below carrying capacity (K)

•generalist niche

•low ability to compete

•early successional species

Prereproductive stage

not mature enough to reproduce

Reproductive stage

those that are capable of reproduction

Postreproductive stage

those that are too old to reproduce

Most populous countries on earth

China, India, and the US.

Demographic Transition

the decline in death rates followed by the decline in birth rates when a country becomes industrialized

Crude birth rate

the number of live births per 1000 persons in a given year

Total Fertility rate

the average number of children born to women in a population during their reproductive years

Replacement-level fertility

(for the whole world) is slightly higher than two children per couple

indicators of health

life expectancy and infant mortality rate

infant mortality rate:

refers to the number of children out of 1,000 that die by their first birthday; a high infant mortality rate is most often associated with under nutrition

Gendercide

the killing of members of a specific sex