quiz #6

Question 1

producers do what with energy

Answer 1

convert low-potential-E raw materials (CO2, H2O, N, P) to high-potential-E organic molecules

Question 2

producers use what to create what from what

Answer 2

producers use light energy to make glucose from carbon dioxide and water

Question 3

how do we impact the carbon cycle?

Answer 3

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

Question 4

draw the phosphorus cycle how does phosphate enter/exit the food chain? how do we impact the cycle?

Answer 4

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.

Question 5

draw nitrogen cycle diagram. how do we affect the nitrogen cycle

Answer 5

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.

Question 6

draw sulfur cycle diagram. how do we affect the sulfur cycle

Answer 6

acid rain and water pollution are major effects. sulfur aerosols temporarily cool the atmosphere

Question 7

which of the cycles are limiting factors

Answer 7

nitrogen and phosphorus

Question 8

draw the nutrient cycles and energy flow

Question 9

what is exponential growth?gives which type of curve?

Answer 9

growth at a constant rate of increase. J

Question 10

what is r

Answer 10

the number of offspring individuals can produce in a given time if resources are limited

Question 11

what is K?

Answer 11

maximum population of a species a habitat can support without being ruined

Question 12

what is logistic growth? where is max rate of population growth? results in which shaped curve?

Answer 12

process slows growth so it levels off near carrying capacity. max rate of population growth occurs halfway to K. S

Question 13

J-shaped growth results from what? explosions often followed by what?

Answer 13

results: unusual disturbances (introduction of a foreign species, changed habitat)
followed by: crashes

Question 14

define biotic potential and recruitment

Answer 14

biotic potential: number of offspring produced under ideal conditions
recruitment: survival of offspring until reproductive stages

Question 15

define environmental resistance

Answer 15

biotic and abiotic factors that limit a population’s increase

Question 16

the biotic potential vs. environmental resistance diagram***

Answer 16

biotic potential: reproductive rate, ability to migrate/disperse, defence mechanisms
environmental resistance: lack of food/nutrients/water/habitat, adverse weather conditions, predators, disease

Question 17

what are r & k strategists’ reproductive strategies. do they have high or low recruitment? how do they like their environments?

Answer 17

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.

Question 18

define the three types of suvivorship. which pattern do r/k fall under?

Answer 18

1) low mortality in early life -> k
2) intermediate survivorship
3) many offspring die young -> r

Question 19

how do r and k strategists respond to human activities? what about r-selected?

Answer 19

r: become pests
k: become rarer/extinct
r-selected: cannot succeed despite high biotic potential

Question 20

define density-dependent factor vs density-independent factors. give an example

Answer 20

density dependent factor: increases with increased population density. disease, predation
density independent factor: don’t relate to density of population. spring freeze.

Question 21

which density factor can regulate a population? give an example of top-down vs bottom-up regulation.

Answer 21

density-dependent.
top: predation
bottom: scarcity of a resource

Question 22

define the critical number. what happens if a population falls below this number?

Answer 22

minimum population base allowing the survival and recovery of a population. if below this number, extinction is almost inevitable

Question 23

name the 5 interactions between species

Answer 23

1) predation +/-
2) competition -/-
3) mutualism +/+
4) commensalism +/0
5) amensalism 0/-