BSC 385 Ch. 9: Population Regulation
exam prep
What is the equation that populations grow? - correct answersdN/dt = rN
What factors affect population growth? - correct answersbiotic/abiotic & effect of density
top-down control - correct answersprocess in which organisms higher in the food chain control the
density and diversity of lower trophic levels
-ex: host-parasite relationship
bottom-up control - correct answersprocess in which organisms lower in the food chain control the
density and diversity of higher trophic levels
-ex: El Nino-driven cycles of the population abundance of galapagos penguins
food chain - correct answershierarchical pattern of energy transfer from primary producers to
consumers
trophic level - correct answersfeeding level; one level in a food chain
density-dependent factor - correct answerspopulation processes that change with the population
density
What factors can act in either a top-down or bottom-up fashion? - correct answersbiotic factors
top-down: predation
bottom-up: energy and biomass available from lower trophic levels
In the absence of resource limitation, populations experience... - correct answersexponential growth
If competition causes higher mortality, which individuals are more likely to die? - correct answersthose
with phenotypes that had organisms less adapted to environment
Bottom-up biotic factors impact... - correct answersthe amount of primary production occurring,
biomass of producers, and availability of resources to consumers
Density-dependence impacts... - correct answersfood supply, number of hosts available to a parasite,
transmission of disease
density-dependent factors - correct answers-population regulation
-effects increase in intensity as the population increases
-dN/dt = rN(K-N)/K
density-independent factors - correct answers-negative effects via disturbance
-indirectly affect populations by changing the equilibrium point or carrying capacity (K)
exam prep
What is the equation that populations grow? - correct answersdN/dt = rN
What factors affect population growth? - correct answersbiotic/abiotic & effect of density
top-down control - correct answersprocess in which organisms higher in the food chain control the
density and diversity of lower trophic levels
-ex: host-parasite relationship
bottom-up control - correct answersprocess in which organisms lower in the food chain control the
density and diversity of higher trophic levels
-ex: El Nino-driven cycles of the population abundance of galapagos penguins
food chain - correct answershierarchical pattern of energy transfer from primary producers to
consumers
trophic level - correct answersfeeding level; one level in a food chain
density-dependent factor - correct answerspopulation processes that change with the population
density
What factors can act in either a top-down or bottom-up fashion? - correct answersbiotic factors
top-down: predation
bottom-up: energy and biomass available from lower trophic levels
In the absence of resource limitation, populations experience... - correct answersexponential growth
If competition causes higher mortality, which individuals are more likely to die? - correct answersthose
with phenotypes that had organisms less adapted to environment
Bottom-up biotic factors impact... - correct answersthe amount of primary production occurring,
biomass of producers, and availability of resources to consumers
Density-dependence impacts... - correct answersfood supply, number of hosts available to a parasite,
transmission of disease
density-dependent factors - correct answers-population regulation
-effects increase in intensity as the population increases
-dN/dt = rN(K-N)/K
density-independent factors - correct answers-negative effects via disturbance
-indirectly affect populations by changing the equilibrium point or carrying capacity (K)
