Population Ecology Flashcards
What is a population’s geographic range?
overall part of the world that the species inhabits
What is a population’s habitat?
specific environment where the species lives
Give an example showing the difference between a population’s range and habitat?
range of giraffe is central, eastern, and southern africa
habitat of giraffe is grasslands
What is the optimal zone for the range of tolerance curve?
the central part of the curve that has conditions that favour maximal reproductive success and survivability
What are the zones of stress for the range tolerance curve?
regions outside the optimal zone where organisms can survive but with reduced reproductive success
What are the zones of intolerance for the range tolerance curve?
outermost regions where organisms cannot survive
What effect does resource partitioning/niche partitioning have on biodiversity?
increases biodiversity
(partitioning means dividing up resources)
What is the fundamental niche?
the full range of environmental tolerances a species could occupy if there was no competition
What is the realized niche?
range of tolerance that is restricted by other species, the space a species occupies given competition
What are invasive species?
non-native species that cause social, economic, or environmental harm, spreads rapidly and has no native predators
What is a type 1 survivorship curve?
high survivorship throughout their life until they reach old age (curve starts off high and remains consistent until old age when it steeply drops)
What is a type 2 survivorship curve?
constant mortality rate regardless of age (negative linear slope)
What is a type 3 survivorship curve?
high mortality at a young age (looks like negative exponential function) lower after they reach established age
In a mark-recapture study what indicates a larger population?
smaller amount of marked individuals being recaptured
When is estimating population size using direct counts useful?
large organisms that are easy to see and that are in small areas
For mobile organisms what do we use to estimate population size?
mark-recapture studies
What is the formula for determining the total population using a mark-recapture study? What do the variables represent?
M/N=R/T–>N=MT/R
N is total population size, M is marked individuals, T is amount recaptured, and R is # of marked that were recaptured
How are population dynamics determined?
births, deaths, immigration, emigration
What is a closed population? When does population size increase/decrease?
isolated from other populations
N increases when births(M)>deaths(D)
N decreases when M<D
What is an open population?
individuals may enter, leave, or stay in the population
N increases when births(M) + immigration(I)>deaths(D) + emigration(E)
N decreases when M+I<D+E
What is the population growth rate?
r=m-d, determined by deaths and births
What is the population change over time determined by?
r and N (growth rate and population size)
deltaN/detlat=rN
When does exponential growth occur?
when r does not change over time, but the instantaneous growth rate increases as the population increases
What is rmax?
when the birth rates are as high as possible and the death rate is as low as possible
what happens to the population if r<0? What about r=0? What about r>0?
shrinks, stable, grows
What are limiting factors?
biotic or abiotic factors that regulate the size of a population
What are the two types of limiting factors?
density-dependent and density-independent
What is the carrying capacity?
the number of organisms of one species that an environment
can support indefinitely
What is logistic growth?
when the population increases rapidly and then levels out at the carrying capacity
What is true for logistic growth when N is small?
(K-N)/K is close to 1 and the growth rate is high
K is carrying capacity
What is true for logistic growth when N is large?
(K-N)/K it gets smaller and the growth rate is low
What is true for logistic growth when N is equal to K?
(K-N)/K is 0 and carrying capacity is reached, growth rate is zero
What are the three stages of density dependent growth?
- initially, growth rate is exponential
- growth rate starts to decline
- growth rate is 0
What does density indepedent growth curves look like?
a series of j-shaped growth curves
What does it mean when a j-shaped curve becomes an s-shaped curve?
the carrying capacity was reached
What would happen if a population exceeds its carrying capacity?
the growth rate would become negative until the population is within its carrying capacity
