population dynamics and growth;ecological principles Flashcards
what causes a species to become invasive
lack of predators
lack of disease
new niches to exploit
reduced competition from native species
who do scientists track population growth
demography
demography
the study of population abundance in varying age categories
depending on the species will depend on how population size are estimated
scientific techniques for accumulating data
quadrats
mark and recapture
life tables
survivorship curves
quadrats
can be set up i the field to determine the absolute number of individuals in an area
mark and recapture
can assist with animals that are very mobile
life tables
examine abundance in various age classes
variables can be calculated based on observed number of individuals in each class
types of growth
exponential and logistic
exponential
unrestricted growth
change in the number/change in time = birth rate - Death rate
dN/dT=rN
logistic growth
restricted growth
dN/dT=rmaxdN/dT=rmaxN (K-N)/K
when close to carrying capacity this is zero, which means population growth is very minimal or zero
population density
competition for resources would eventually limit growth; also build-up of waste would become fatal
carrying capacity
the optimal size of a population that an environment can maintain
ecological characteristics that are density-dependent
food
water
shelter
nesting space
mates
build up of waste products
other factors that might control populations: density independent factors
weather
natural disasters
pollution
characteristics of K selected species
mature late
greater longevity
increased parental care
increased competition
fewer offspring
larger offspring
characteristics of r selected species
mature early
lower longevity
decreased parental care
decreased competition
more offspring
smaller offspring
population distribution
uniform
random
clumped
species interactions
interspecific and intraspecific competition
predation
parasitism
mutualism
interspecific competition
competition between two species for resources- usually not a direct battle, but rather one species evolves the ability to become more efficient than another at gaining resources
predation
when one species consumes another
this can also extend to plant/herbivore relationships
evolved patterns based on predation
camouflage
chemical warfare
warning coloration
mimicry
Behavioral strategies
parasitism
one species feeds off of another organism
ectoparasites-live on the outer surface of the host organism
endoparasites
live inside the host organism
coevolution
when two species interact over long periods of time and changes in the gene pool of one species lead to changes in the gene pool of the other
commensalism
an interaction that benefits one but has little, if any, beneficial or harmful effect on the other
mutualism
two species are both benefitted by the interaction
trophic
feeding
keystone species
skewed distribution of interaction strengths occur in food webs
indicates a species whose effect on the community is disproportionately large relative to their abundance
have a large impact relative to their biomass
dominant species
constitute a large fraction of a community’s biomass and whose impacts are large, but not disproportionate to their abundances
