Test 3 vocab Flashcards
population ecology
- the study of populations (the numbers of individuals of a particular species at a given time and location), and their interactions with the environment
- mortality
density
the number of individuals of a species per unit space (volume)
births
- add to a population;
- natality
immigration
- the influx of new individuals into a population from other area
- the migrations of individuals into the population
- i
deaths
- which remove individuals from a population
- mortality
emigration
- the movement of individuals out of a population
- the migration of individuals out of the population
dispersion
the pattern of spacing among individuals within the boundaries of a population
clumped dispersion
type of distribution where individuals aggregate in patches
uniform dispersion
type of distribution where individuals are more evenly distributed than would be expected randomly
random dispersion
type of distribution where the position of each individual is independent of other individuals (unpredictable spacing)
demography
the study of changes over time in the vital statistics (birth and eath rates, ect.) of population
life table
an age-specific summary of the survival pattern of a population
cohort
a group of individuals of the same age from birth until all of the individuals are dead
survivorship curve
is a graphic way of representing the data in a life table (age-specific mortality)
Type I curve
low death rates during early and middle life (flat curve at the state) and an increase in death rates among older age groups (curve drops steeply)
Type II curve
a constant death rate over the organism’s life span
Type III curve
high death rates for the young (curve drops steeply at the start) and a lower death rate for survivors( curve flattens out)
reporductive table (fertility schedule)
is an age-specific summary of the reproductive rates in a population
ΔN
is the change in population size
Δt
is the change in time (generation time or life span)
b
is the natality (birth) rate; aka per capita birth rate
natality rate (per capita birth rate)
the number of offspring produced per unit time per average individual (per capita) of the population
d or m
the mortlality (death) rate; aka per capita death ate
mortality (death) rate
the # of expected deaths per unit time in a population
N
the population size
mathmatical models describe population growth
- ΔN/Δt=bN-dN
- r=b-d to find the rate of growth
- dn/dt=rN to find to total growth during set time
r
the per capita rate of change (growth rate)
zero population growth
the population is stable; occurs when natality and mortality are equal
dispersal
the movement of individuals among populations
exponential population growth
growth of a population increases at a constant rate (only occurs under idealized conditions)
J-shaped curve
when population size is plotted over time showing exponential growth
carrying capacity (K)
the maximum population size the environment can sustain
logistic population growth
- model describes how a population grows more slowly as it nears its carrying capacity
- dN/dt=rN[(K-N)/K]
S shaped growth curve
growth regulated by environmental resistance shows
semelparity (big-bang reproduction)
reproduction in which an organism produces all of its offspring in a single event
iteroparity (repeated reproduction)
reproduction in which an organism produces offspring over many years (repeatedly)
R-strategists
organism that prossess traits to increase the growth rate (r)
r-selection
- density-indepentent selection
- selects for life history traits that maximize reproductive success in uncrowded environments (abandoned agriculture field or burned area)
K-strategists
organisms that posses traits to ensure that the population of a species doesn’t exceed the carrying capacity
K-selection
- density-dependent selection
- selects for life history traits that are sensitive to population density
density -independent factors
limit population size
density-dependent factors
- regulate population size. birth rates fall and death rates rise with population density
- competions for resources
- toxic wastes
- predation
- intrinsic (physiological) factors
- territoryiality
- disease
competition for resources
- in crowded population, increasing poulation density intensifies competition for resources and results in a lower birth rate
- intraspecific
- interspecific
intraspecific
competions exists between members of the same species
interspecific
competion exists between memebers of different species
age structure
the relative number of individuals of each age in a population
people over population
is a result of too many people living in certain area
consumption overpopultation
is a result of people over-utilizing resources
