quiz #6 Flashcards
producers do what with energy
convert low-potential-E raw materials (CO2, H2O, N, P) to high-potential-E organic molecules
producers use what to create what from what
producers use light energy to make glucose from carbon dioxide and water
how do we impact the carbon cycle?
we are diverting/removing 40% of the photosynthetic productivity of land plants. burning fossil fuels has increased atmospheric CO2 by 35%. deforestation and soil degradation release significant amounts of CO2 into the atmosphere
draw the phosphorus cycle how does phosphate enter/exit the food chain? how do we impact the cycle?
enters via cellular respiration and exits by decomposers.
phosphorus is mined and made into fertilizers, animal feeds, detergents. when added to soil, it can stimulate production. human applications have tripled the amount reaching the oceans, accelerating the cycle. excess phosphorus in water causes severe pollution -> can cause overgrowth of algae, too much bacteria, death of fish.
draw nitrogen cycle diagram. how do we affect the nitrogen cycle
crops (legumes) draw N from the air which increases the rate of N fixation. nonleguminous crops are fertilized with nitrogen from industrial fixation. we are more than doubling the rate of nitrogen moving from air to land. nitric acid has destroyed lakes, ponds, forests. atmospheric nitrogen adds to ozone pollution, climate change, stratospheric ozone depletion, eutrophication of waterways.
draw sulfur cycle diagram. how do we affect the sulfur cycle
acid rain and water pollution are major effects. sulfur aerosols temporarily cool the atmosphere
which of the cycles are limiting factors
nitrogen and phosphorus
draw the nutrient cycles and energy flow
what is exponential growth?gives which type of curve?
growth at a constant rate of increase. J
what is r
the number of offspring individuals can produce in a given time if resources are limited
what is K?
maximum population of a species a habitat can support without being ruined
what is logistic growth? where is max rate of population growth? results in which shaped curve?
process slows growth so it levels off near carrying capacity. max rate of population growth occurs halfway to K. S
J-shaped growth results from what? explosions often followed by what?
results: unusual disturbances (introduction of a foreign species, changed habitat)
followed by: crashes
define biotic potential and recruitment
biotic potential: number of offspring produced under ideal conditions
recruitment: survival of offspring until reproductive stages
define environmental resistance
biotic and abiotic factors that limit a population’s increase
the biotic potential vs. environmental resistance diagram***
biotic potential: reproductive rate, ability to migrate/disperse, defence mechanisms
environmental resistance: lack of food/nutrients/water/habitat, adverse weather conditions, predators, disease
what are r & k strategists’ reproductive strategies. do they have high or low recruitment? how do they like their environments?
r: produce lots of young, leave their survival to nature. low recruitment. rapidly changing environment, rapid reproduction, rapid everything
k: lower biotic potential so care for and protect young. higher recruitment. live longer, larger, stable environment.
define the three types of suvivorship. which pattern do r/k fall under?
1) low mortality in early life -> k
2) intermediate survivorship
3) many offspring die young -> r
how do r and k strategists respond to human activities? what about r-selected?
r: become pests
k: become rarer/extinct
r-selected: cannot succeed despite high biotic potential
define density-dependent factor vs density-independent factors. give an example
density dependent factor: increases with increased population density. disease, predation
density independent factor: don’t relate to density of population. spring freeze.
which density factor can regulate a population? give an example of top-down vs bottom-up regulation.
density-dependent.
top: predation
bottom: scarcity of a resource
define the critical number. what happens if a population falls below this number?
minimum population base allowing the survival and recovery of a population. if below this number, extinction is almost inevitable
name the 5 interactions between species
1) predation +/-
2) competition -/-
3) mutualism +/+
4) commensalism +/0
5) amensalism 0/-
