Ch. 53: Density and Dispersion Flashcards
Unlock all answers in this set
Unlock answersquestion
what are the differences between density and dispersion of a population?
answer
density is the amount of people per unit area, dispersion is the pattern of spacing of individuals
question
what is clumped dispersion
answer
individuals are aggregated in patches usually where conditions are ideal (food, nutrition, soil is right etc)
question
the most common type of dispersion
answer
clumped
question
what is uniformed dispersion?
answer
even pattern of dispersion results from direct ineractions btwn individuals in the population
question
example of uniformed dispersion
answer
some plants secrete chemicals that inhibit the growth of other plants near them so they don't compete for resources
question
territoriality (defense of bounded physical space in social interactions)
answer
may cause uniformed dispersion. for example, king penguines
question
this is rarer than clumped dispersion
answer
uniformed dispersion
question
random dispersion
answer
independent from the individuals choices, unpredictable spacing
question
demography
answer
the study of vital statistics - death, birth rates, immigration, emmigration - of a population and how they change overtime
question
Nt=No+B-D+I-E
answer
No= population now, D=death, B= birth, I=immigration, E=emmigration
question
type 1 survirorship curve
answer
high survivorship as young & middle age, low survivorship as age increases
question
type II survivorship
answer
steady survivorship throughout life, straight diagnoal line
question
type III survivorship
answer
low survivorship during youth, high survivorship during old age: average individual doesn't make it past early stage
question
ex of type II
answer
ground squirels
question
ex of type III
answer
oysters
question
ex of type I
answer
human beings
question
what is a life history?
answer
when an individual reaches reproductive maturity, and how often? and are they small but plentiful?
question
what determines the equilibrium?
answer
immigration and extinction
question
selmelparous
answer
reproducing once in a lifetime
question
what is the benefit of selelparoty?
answer
leaving more resources for future generations
question
iteroparity
answer
reproducing multiple times over a life time which keeps a population thriving and survirorship is high and constant
question
what are trade offs in life history?
answer
high reproduction rate and occurrence at an earlier age, parents investment in offspring, low survival.
question
reproduction trade offs
answer
when to reproduce (age/maturity) how often and investment in offspring per reproducive episode
question
Nt-No+B-D=r
answer
intrinsic rate of growth
question
dN over dT = 1N
answer
exponental growth model
question
dN over dt = rN (K-N over K)
answer
logistic growth, where K = carrying capacity
question
K (big) - N (big) over K (big) is equivalent to
answer
small over big
question
A \"k\" selected population is
answer
low fecundity (the capacity of creating young esp. in great numbers) and high survivorship, iteroparous reproduction, small brood size, reproductive delay
question
An \"R\" selected population
answer
many offspring, low survivorship, high fecundity
question
an example of an \"r\" selected population
answer
mosquitoes
question
an example of a \"k\" selected pop
answer
humans
question
what kind of factors regulate population growth?
answer
habitat, food, water, competition, predators, disease (which are all density dependent factors) which become more important as a population increases
question
floods and hurricanes are
answer
density independent factors
question
a country that exudes rapid growth would be
answer
afghanistan, where the majority of the population are younger individuals
question
an example of a country that is slow growth is
answer
the united states, where majority of population tends to be in the middle and young age range
question
a no growth country might be
answer
italy where population is low for younger individuals and higher middle aged groups
question
how deos an environments K affect the per capita rate of increase of a pop
answer
regulation
question
r
answer
selection for traits that maximize reproductive success in low densitites
question
K-N
answer
two extremes in a range of actual histories
question
if competitoin is intense in juveniles but adults have longer survorship selection may favor
answer
K selected pops: iteroparious reproduction, small brood size, reproductive delay, large eggs, low intrinsic rate of increase
question
if populations tend to experience many periods of exponential growth selection may favor
answer
R selected pops. semelparous reproduction, fast development, large brood sizes, maximize their intrinsic rate of increase
question
what problems may come about when trying to estimate Earth's K for the human species
answer
will run out of space & food due to overreproduction, nonrenewable resources, room for our waste
question
according to the logistics growth model [ dN over dt = rN (K-N over K) ] A) the # of individuals added per unit time is greatst when N is close to zero B) population growth is zero when N =K C) the birth rate approaches zero as N approaces K D) the per capita growth rate increases as N approaches K
answer
B) the population growth is zero when N=K
