Z- Bio Exam

Front 1

Carrying capacity (K)

Back 1

is defined as the maximum stable population size that a particular
environment can sustain over a relatively long period of time.

==Carrying capacity changes over space and time and is determined by the environment.
The amount of food, number of nesting sites, access to shelter, etc. will determine the carrying
capacity of an area.

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Front 2

Crowding and competition

Back 2

Crowding and competition for resources can affect both birth rates and death rates. A decrease
in b or an increase in d will lower r - the population growth rate. Population growth will slow.

Front 3

logistic growth equation.

Back 3

N<K population growth is rapid, but when N approaches K
population growth slows.

-dN/dt = rmax (N) K-N/K - this term causes population growth to slow as
N approaches K.

Front 4

But other populations do not exhibit perfect logistic growth

Back 4

other factors are responsible for
determining population growth. For example, Daphnia can over exploit their bacterial food and
thus maintain lower population density than the expected carrying capacity.

Front 5

High density

Back 5

High density - low population growth (resources are limited and competition is high)

Front 6

Low density

Back 6

Low density - high population growth (resources are abundant and comp is low)

Front 7

K-selected populations

Back 7

Populations that tend to exist at densities near the carrying capacity will have adaptations for competitive ability and efficient use of resources

Front 8

r-selected populations

Back 8

Populations that are found in variable environments in which populations fluctuate in size, or in
habitats where there is little competition, are known as r-selected populations (opportunistic
populations). Population growth is rapid.
-R-SELECTED ROACHES

Front 9

Populations that seem to demonstrate either r- or K-selected population growth

Back 9

Populations that seem to demonstrate either r- or K-selected population growth tend to exhibit
similar life history characteristics. For example, K-selected populations tend to take a long time
to mature, have long lifespans, low mortality rates, few offspring per reproductive effort, and
extensive parental care.

Front 10

r-selected populations tend

Back 10

r-selected populations tend to be comprised of individuals that mature quickly, have
short lifespans, high mortality rates, many offspring per effort, and no parental care.
In nature, many populations exhibit a mix of these strategies.