ch 53 Flashcards
Population ecology explores the ________, _______, ______ of populations
abundance
dispersion
age structure
A ________ is a group of individuals of a single species living in the same general area
population
populations are described by their _______ and _______
boundaries and size
The number of individuals is called
population size
the number of individuals per unit area or volume
density
the pattern of spacing among individuals within the boundaries of the population
Dispersion
_______ can be used to estimate densities and total population sizes
sampling techniques
Population size can be estimated by? (3)
1) extrapolation from small samples
2) an index of population size (e.g., number of nests)
3) the mark-recapture method
Whats the formula for the mark and recapture method?
N=sn/x
Scientists capture, tag, and release a random sample of individuals (__) in a population
Marked individuals are given time to mix back into the population
Scientists capture a second sample of individuals (__), and note how many of them are marked (__)
Population size (__) is estimated by N=sn/x
s, n, x, N
the influx of new individuals from other areas
Immigration
the movement of individuals out of a population
Emigration
What are the 3 types of dispersion
1) clumped
2) uniform
3) random
The most common pattern of dispersion is _______
clumped
Clumped dispersions are influenced mainly by _______
resource availability
clumped dispersions can also be influenced by _______ and _______
Mating behavior; group defense against predators
Dispersion in which individuals are evenly distributed
Uniform dispersion
Uniform dispersion may be influenced by social interactions such as _______
territoriality
the defense of a bounded space against other individuals
territoriality
Dispersion in which the position of each individual is independent of other individuals
random dispersion
When does random dispersion occur?
absence of strong attractions or repulsions among individuals
the study of these vital statistics of a population and how they change over time
Demography
an age-specific summary of the survival and reproductive rates within a population
Life table
life tables are often made by following the ________ of a _______, a group of individuals of the same age
fate; cohort
a group of individuals of the same age is called a?
cohort
A _______ is a graphic way of representing the data in a life table
survivorship curve
What type of curve is: Low death rates during early and middle life and an increase in death rates among older age groups
Type I
What type of curve is: A constant death rate over the organism’s life span
Type II
What type of curve is: High death rates for the young and a lower death rate for survivors
Type III
Change in population size (total) =
births + immigrants - Deaths - emigrants
change in N/ change in T =
Births (B) - Deaths (D) which can be represented as (R)
population increase under idealized conditions
Exponential population growth
The maximum population size the environment can support
Carrying capacity (K)
In the _______ model, the per capita rate of population growth approaches zero as the population size nears carrying capacity (K)
logistics population growth
What are the 3 key components of organism’s life history?
1) Maturity (The age at first reproduction)
2) how often the organism reproduces
3) clutch size (How many offspring are produced per reproductive episode)
species that reproduce once and die
semelparity
species that produce offspring repeatedly
iteroparity
there is a _______ between survival and paternal care (brood size) in European kestrels
trade-off
Selective pressures influence trade-offs between the _______ and _______ of offspring
number and size
Are sea turtles r or K selected?
They’re a mixture
they are K selected because they mature late, expend a lot of energy to reach birth place to lay eggs, and live a long time
they are r selected because they produce a lot of offspring and don’t undergo parental care
What are the 2 types of population changes regarding density?
density-independent
density-dependent
In density-_______ populations, birth rate and death rate do not change with population density
independent
In density-_______ populations, birth rates fall and death increase with rising population density
dependent
What are the 6 density-dependent factors?
1) competition for resources
2) disease
3) predation
4) territoriality
5) toxic wastes
6) intrinsic factors
In crowded populations, increasing population density intensifies _______ and results in a lower birth rate
competition for resources
What factor is characterized in dense populations as pathogens can spread more rapidly
disease
As a prey population builds up, _______ may feed preferentially on that species
predators
_______ can limit population density when individuals compete for limited space
territoriality
Accumulation of _______ can contribute to density-dependent regulation of population size
toxic wastes
For some populations, _______ (physiological) appear to regulate population size
intrinsic factors
describe boom or bust cycles
Increase and decrease of population following a cycle of time periods
When a population becomes crowded and resource competition increases, _______ often increases
emigration
groups of populations linked by immigration and emigration
Metapopulations
Local populations in a metapopulation occupy patches of _______ habitat surrounded by _______ habitat
suitable; unsuitable
the relative number of individuals of each age in a population
age structure
One important factor affecting population growth is a country’s _______
age structure
