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33 terms

Ecology Unit

Summer Hell
STUDY
PLAY
Species/Population/Community
____ is a group of similar looking organisms that interbreed in nature and produce viable fertile off spring
_____ is a group of individuals of the same species living in an area
_____is a group of populations of different species in an area
Dispersal
movement of individuals away from centers of high population density or from their area of origin
climograph
a plot of the temperature and precipitation in a region
ecotone
area of intergradation- may be wide or narrow
Demography
the study of the vital statistics of a population and how they change over time
life table
an age-specific summary of the survival pattern of a population
cohort
best made lifetable-a group of individuals of the same age being monitored
survivorship curve
graphic way of representing the data in a life table
Type III
high death rates for the young, then a slower death rate for survivors
Type II
the death rate is constant over the organism's life span
Type I
: low death rates during early and middle life, then an increase among older age groups
Classification of Survivorship Curves (3)
TYPE I
TYPE II
TYPE III
reproductive table
an age-specific summary of the reproductive rates in a population
Another Name for a fertility schedule
reproductive table
factors to life history
-The age at which reproduction begins
-How often the organism reproduces
-How many offspring are produced during each reproductive cycle
Life history traits are what?
Where are they reflected in?
Life history traits are evolutionary outcomes reflected in the development, physiology, and behavior of an organism
Semelparity
or big-bang reproduction, reproduce once and die
Iteroparity
repeated reproduction, produce offspring repeatedly
Highly variable or unpredictable environments : favor which kind of reproduction?
big-bang reproduction : semelparity
dependable environments may favor repeated reproduction : favor which kind of reproduction?
favor repeated reproduction : iteroparity
Organisms sometimes have finite resources what could this lead to?
Trade offs between survival & reproduction
Exponential Pop Growth
is population increase under idealized conditions it is a J-shaped curve
^N/^t = rN
n = population size / t-time / r = per capita rate increase
per capita rate increase =?
r= birth-death
Rebounded populations cold be shown by?
j shaped curves of exponential growth
Does exponential growth continue forever?
no there eventually is a CARRYING CAPACITY (K)
Carrying Capacity
(K) maximum population size the environment can support
K-selection, or density-dependent selection
, selects for life history traits that are sensitive to population density
r-selection, or density-independent selection,
selects for life history traits that maximize reproduction
In density-dependent populations, birth rates fall or rise? death rates? with population density
birth rates fall / death rates rise with population density
In density-independent populations, birth rates fall or rise? death rates? with population density
birth rate and death rate do not change with population density
Negative Feedback Examples
Density-dependent birth and death rates
Negative Feedback Examples are affected by what?
competition for resources, territoriality, disease, predation, toxic wastes, and intrinsic factors