Term
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Definition
| number of individuals per unit of area (for terrestrial organisms) or volume (for for organisms that live in the air, soil, or water) |
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Term
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Definition
total number of individuals in a population
*only used in small population areas where individuals can be distinguished |
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Term
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Definition
| area where a species may be found |
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Term
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Definition
| particular environment in which an organism lives |
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Term
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Definition
| area of a particular habitat surrounded by other habitat types that are less suitable for that organism |
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Term
| population densities are dynamic: |
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Definition
| meaning they change over time |
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Term
| # of individuals in a population at some time in the future= |
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Definition
# now + # that are born - # that die
Nt+1 = Nt + B - D
N=population size
B=# of births in time interval from time t to time t+1
D=# of deaths in same interval |
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Term
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Definition
"birth death" model of population change
*accounts for births and deaths changing population size |
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Term
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Definition
| how much a population changes over time and how fast it makes these changes |
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Term
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Definition
Nt+1 - Nt = ΔN = B - D
ΔN = B-D = B-D = B-D
ΔT (t+1)-t 1 |
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Term
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Definition
| Change in population size |
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Term
| per capita birth rate (b) |
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Definition
| birth rate per individual |
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Term
| per capita death rate (d) |
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Definition
| death rate per individual |
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Term
| total birth and death rate in a population |
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Definition
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Term
per capita growth rate (r)
(substitute "r" for "(b-d)") |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| no change in population size |
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Definition
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Term
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Definition
| time course of growth and development, reproduction, and death during an average individual's life |
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Term
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Definition
summary of info about the progression of individuals in a population through the various stages of their life cycles
*contains survivorship and fecundity
*used to calculate per capita growth rate (r) |
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Term
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Definition
| fraction of individuals that survive from birth to different life stages or ages |
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Term
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Definition
| average number of offspring each individual produces during its life stages or ages if they do survive |
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Term
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Definition
fraction of individuals that do not survive from birth to a given stage or age
(mortality= 1 survivorship) |
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Term
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Definition
| materials and energy required by an individual and the time available to acquire them |
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Term
| difference btwn resources and conditions |
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Definition
resources can be used up (ex: mineral nutrients, photons of light, time, space, or food)
conditions are experienced, not consumed |
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Term
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Definition
states that once an organism has acquired a unit of some resource, it can be used for only one function at a time
*meaning organisms have to divide the resources they are able to obtain among competing functions |
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Term
multiplicative growth
(exponential growth) |
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Definition
| population growth in which a constant multiple of the population size is added to the population during successive time intervals |
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Term
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Definition
| population growth in which a constant number of individuals is added to the population during successive time intervals |
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Term
| doubling time in multiplicative growth |
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Definition
| can be calculated if we know r |
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Term
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Definition
| r decreases as the population becomes more crowded |
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Term
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Definition
when r=0 and the population size stops changing
*thought of as the number of individuals the environment can support indefinately |
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Term
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Definition
| max possible value in uncrowded conditions - an amt that is a function of density |
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Term
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Definition
| limiting number of individuals an environment can support without be crowded |
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Term
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Definition
| population divided into subpopulations, among which there are occasional exchanges of individuals |
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Term
BIDE model
(Number of individuals in a population at some time in the future=) |
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Definition
immigrants(I): individuals that move into a population
emigrants(E): indivials that move out of a population
(# now + # that are born + # that immigrate - # that die - number that emigrate) |
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Term
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Definition
| connection btwn habitat patches through which organisms can disperse; plays a critical role in maintaining subpopulation |
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Term
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Definition
| individuals are not limited by food or disease, but by carrying capacity |
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Term
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Definition
*organisms cannot simultaneously invest in both defense and growth
*if a species invest in reproduction, they will grow more slowly |
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Term
| Type I Survivorship Curve |
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Definition
| characterized by high survival in early and middle life, followed a rapid decline in survivorship in later life. Humans are one of the species that show this pattern of survivorship. |
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Term
| Type III Survivorship Curve |
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Definition
| greatest mortality is experienced early on in life, with relatively low rates of death for those surviving this bottleneck. This type of curve is characteristic of species that produce a large number of offspring |
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Term
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Definition
| study of population structure and of the processes by which it changes |
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Term
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Definition
| ratio of males to females in a population |
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Term
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Definition
quantity used in population biology and demography to reflect the relative size of intervals of offspring production
*usually expresses the average age of breeding females within a population. |
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Term
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Definition
| Categorization of the population of communities or countries by age groups, allowing demographers to make projections of the growth or decline of the particular population |
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Term
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Definition
| group of similar aged organisms |
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