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What factors increase a population size?
Births and immigration
What factors decrease a population size?
Death and emigration
what does CBR stand for?
Crude birth rate
what does CDR stand for?
Crude death rate
What does TFR stand for?
Total fertility rate
What is the equation for a countries annual population growth rate?
Gr=(CBR+immigration) - (CDR+immirgation)/10
What is the equation to calculate a population doubling time
70/ growth rate
Age pyramid shape ( developing and developed countries)
Developing countries = pyramid
Developed countries = column
Net migration ( developing countries and developed countries )
Developing = negative
Developed = positive
TFR ( developing countries and devolved countries)
Developing = bigger then 2
Developed = under 2
Population
The individuals that belong to the same species and live in the given area at particular time
Community
all of the populations of organisms within a given area
Population ecology
the study of factors that cause population to increase or decrease
population size ( n)
the total number of individuals within a defined area at the given time
population density
The number of individuals per unit area at a given time
Births death and migration.
the study of factors that cause population to increase or decrease
population distribution
a description of how individuals are distributed with respect to one another
sex ratio-
the ratio of males to females in a population
age structure
a description of how many individuals fit in a particular age category and a population
limiting resources
a resource that a population cannot live without and that occurs in quantity slower than the population will require to increase in size.
density dependent factor
effect to the influences an individual probability of survival and reproduction in a manner that depends on the size of the population
carrying capacity (k)-
the limit of how many individuals in a population that environment can sustain
density independent Factor-
a factor that has the same effect on individual probability of survival and the amount of reproduction of any population size
population growth models
mathematical equations that can be used to predict population size at any moment in time
population growth rate-
the number of Offspring in an individual can produce in a given time period, minus the deaths of individual or it's offering during the same period
Intrinsic growth rate (r )
The maximum potential for growth of population under an ideal conditions with unlimited resources
Exponential Growth Model-
a growth model that estimates the population in future size and (NT) after a period of time ( T) based on the intrinsic growth rate are and the number of reproducing individuals currently in the population(n0)
J shaped curve
the curve of the exponential growth model when graphed
logistic growth model-
a growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment.
s shaped curve
the shape of a logistic growth model and graft
Overshoot
when a population becomes larger than the environment carrying capacity
Die-off
a rapid decline in the population due to death
k-selected species
a species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity
r-selected species
A species that has a high and twisted growth weight, which often leaves the population overshooting and die offs.
Survivorship curve
a graph that represents the distinct patterns of species survival as a function of age
type 1 survivorship curve
a pattern of survival over time in which these there is high survival throughout most of the life span, but that individual starts to die in large numbers as they approached old age
type 2 survivor curve
a pattern of survival over time in which these related constant decline in survivorship throughout most of the lifespan
type 3 survivorship curve-
a pattern of survival over time in which theater is slow ship early in life which fruit individuals reach adulthood.
Biotic potential
The maximum rate at which the population of a given species can increase when there are no limits on its rate of growth.
Invasive species
a species that spreads rapidly across large areas
Ecological succession
A series of predictable and orderly changes within an ecosystem over time
generalist species
A species able to thrive in a wide variety of environmental conditions and that can make use of a variety of different resources
speciales species
A species that uses a relatively small proportion (in extreme cases only one) of the available resources types.
