Chapter 52 Flashcards
The specific environment in which a population lives as a characterized by its biotic and abiotic features
habitat
The number of individuals in a population at a specified time
population size
The number of individuals per unit area or per unit volume of habitat
population density
The spatial distribution of individuals within a population’s geographical range
dispersion
a pattern of distribution in which the individuals in a population are distributed unpredictably in their habitat
random dispersion
A pattern of distribution in which individuals in a population are grouped together
clumped dispersion
A pattern of distribution in which the individuals in a population are evenly spaced in their habitat
uniform dispersion
A statistical description or graph of the relative numbers of individuals in each age class in a population
age structure
The average time between the birth of an organism and the birth of its offspring
generation time
The relative proportions of males and females in a population
sex ratio
What is the difference between a population’s size and its density?
A population’s size is simply the number of individuals it contains. Its density is the number of individuals per area r volume of habitat occupied
What do the 3 patterns of dispersion imply about the relationships between individuals in a population
a clumped pattern of dispersion implies that individuals in the population help each other or that some vital resource in the environment also has a clumped distribution. A uniform pattern of dispersion implies that individuals in the population repel each other. A random pattern of dispersion does not imply either positive or negative interactions among individuals in the population.
movement of organisms into a population
immigration
The movement of individual out of a population
emigration
The statistical study of the process that change a population’s size and density through time
Demography
A chart that summarizes the demographic characteristics of a population
life table
A group of individuals of similar age
cohort
The proportions of individuals alive at the start of an age interval that died during that age interval
age-specific mortality
The proportion of individuals alive at the start of an age interval that survived until the start of the next age interval
age-specific survivorship
The average number of offspring produced by surviving females of a particular age
age-specific fecundity
Graphic display of the rate of survival of individuals over a species’ life span
survivorship curve
What statistics are usually included in a life table?
A life table usually summarizes statistics about the age-specific rate, age-specific mortality rates, and age-specific fecundity of a population
Which type of survivorship curve is characteristic of humans in industrialized countries?
humans in the industrialized countries exhibit Type I suvivorship curves because they provide lots of care to their offspring, thus reducing infant and childhood mortality to low levels
The lifetime pattern of growth, maturation, and reproduction that is characteristic of a population or species
life histories
the total amount of energy that an organism can accumulate and use to fuel its activities
energy budget
The amount of energy invested in offspring- in the form of the energy stored in eggs or seeds or energy transferred to developing young through a placenta- before they are born
passive parental care
Parents’ investment of time and energy in caring for offspring after they are born or hatched
active parental care
to what 2 broad categories of activities do children devote their energy budget?
Children spend most of their energy on growth and maintenance; they devote energy to reproduction later in life
Why do fecundity and the amount of parental care devoted ot each offspring exhibit an inverse relationship?
fecundity and the amount of parental care devoted to each offspring exhibit an inverse relationship because organisms that produce few offspring can devote substantial time and energy to each, whereas those that produce many offspring can devote only minimal time and energy to each
model that describes unlimited population growth
exponential model of population growth
The difference between the per capita birth rate and the per capita death rate of a population
per capita growth rate
A circumstance in which the birth rate of a population equals the death rate
zero population growth
The maximum possible per capita population growth rate in a population living under ideal conditions
intrinsic rate of increase
The maximum size of a population that an environment can support indefinitely
carrying capacity
model of population growth that assumes that a population’s per capita growth rate decrease as the population gets larger
logistic model of population growth
The dependence of 2 or more individuals in a population on the same limiting resource
intraspecific
the delayed response of organisms to changes in environmental conditions
time lag
how does the prediction of the exponential model of population growth differ from that of the logistic model?
The model of exponential population growth predicts unlimited population growth through time, generating a J-shaped curve of population size versus time. The logistic model predicts that population growth slow down as the population approaches its carrying capacity, generating an S-shaped curve of population size versus time
What is carrying capacity? is it a property of a habitat or of a population?
carrying capacity is the maximum number of individuals in a population that an environment can support. The carrying capacity is thus a property of the environment with reference to a particular population
What is time lag?
A time lag is a delay in a population’s response to a changing environment. It may cause population’s size to oscillate around its carrying capacity
description of environmental factors for which the strength of their efect on a population varies with the population’s density
density-dependent
Description of environmental factors for which the strength of their effect on a population does not vary with the population’s density
density-independent
a short-lived species adapted to function well in a rapidly changing environment
r-selected species
long-lived species that thrive in more stable environments
K-selected species
a group of neighboring populations that exchange individuals
metapopulation
in metapopulation analyses, a population that is either stable or increasing in size
source population
in metapopulations analysis, a population that routinely declines in size after being replenished by immigrants from a source population
sink population
How can you tell whether an environmental factor causes denisity-dependent or density-independent effects on a population?
The effects of density-dependent factors gets stronger(that is, they affect a larger percentage of the individuals in the population) as the population’s density increase. The effects of density-independent factors do not change(that is, they affect the same percentage of the individuals in a population) as the population’s density changes
Are the effects of infectious diseases on populations more likely to be density-dependent or density-independent?
The effects of infectious diseases are usually density-dependent because disease-causing pathogens spread more quickly through dense populations of the organisms they infect
A graphical depiction of the historical relationship between a country’s economic development and its birth and death rates
demographic transition model
a program that educates people about ways to produce an optimal family size on an economically feasible schedule
family planning program
How have humans sidestepped the controls that regulate populations of other organisms?
humans have sidestepped the controls that regulate the populations of other organisms by expanding their geographical range to include a wide variety of habitats, by increasing the carrying capacity through agricultural production and by decreasing their death rate through the introduction of medical care and improved sanitation
how does the age structure of a population influence its future population growth?
the age structure of a population influences its future population growth by determining how many individuals will reach reproductive age in the future. populations with a bottom-heavy age structure will experience a growth spurt when children alive today reach sexual maturity. populations with a more even age structure will not experience a dramatic future increase in population size
The overall spatial boundaries within which a population lives
geographical range
