exam 4

Question 1

differentiate between gpp and npp and understand controls in terrestrial and aquatic enviroments

Answer 1

gross primary production - total biomass produced by all the autotrophs in an ecosystem
net primary production- amount of biomass left over after autotrophs have met their own energetic needs

Question 2

define trophic cascades and descrobe how they control plant biomass

Answer 2

wolfs in yellowstone

Question 3

understand mechanisms nehind compensatory growth

Answer 3

lower rates of respiration due to lower biomass?
reduced self shading- a less dense bush would have more overall access to sunlight
improved water relations- again less leaves means more water going to remaining leaves

Question 4

describe how energy limits the # of trophic levels in an ecosystem

Answer 4

theres only so much energy to cycle around, the less energy the primary producers make the less energy there is to sustain more levels

Question 6

terminology: pool vs flux, sink vs sourse

Answer 6

pool-where a nutrient is “stored” or held in a certain part of the ecosystem(marine rock)
flux- the movement of said nutrients
sink-where that nutrient is absorbed faster than it is released
source-opposite of sink

Question 7

descruibe main characteristics of and differences between C,N and P cycles.

Answer 7

P- assential to life processes, not as much as N, stored in soil but not in a usable form
N- used in life functions, pools in the atmosphere but few organisms can use N2
C-ORGANIC molecules, fluxes through photosynthesis, either cycles quickly or pools for longer periods of time

Question 8

describe multiple factors that affect decomposition rate

Answer 8

water, evaporation, nitrogen(less N increases toughness), richness(increases possible detritivores,

Question 9

give examples of how organisms may affect nutrients.

Answer 9

actual output of nutrients by different organisms in waste(animals secretions or plants giving off litter), movement of nutrients by disturbance,

Question 11

understnad the differences betwwen primary and secondary succession; pioneer and climax communties

Answer 11

primary succesion is what grows after NEW soil is made,
secondary succession is the repopulation of things that where previously wiped out, soil is the same soil

pioneer- the first organisms to settle
climax- the organisms that stay up until new distrubance is made

Question 12

describe what happens to rchness with succession

Answer 12

richenss increases as time goes on, but it depends on the environment and type of succesion/disturbnace on how quickly that richness comes back

Question 13

differentiate between resistnace and resilienc. what mechanims do plants use for each

Answer 13

resistance-ability to prevent affects of disturbnace
- thick or hard stems or bark(fire), deep roots(wind or floods)
resilience-the ability to spring back from a disturbance
-fast growing

Question 15

explain the links betwen island area and species richness

Answer 15

the bigger the island the more the richness, isolation does not allow for richness or diversity

Question 16

describe how immigration and extiction (and richness) are determined by area and isolation (island biography)

Answer 16

immigration decreases as total # of species increase, but possibility of extinction also increases as # of species present increase

immigration- more species the less smapece for new
extinction- more species the more potential for extinction because more species= more competition and smaller population sizes withing each species

Question 17

describe experimental apprchaces to explore contrls of island richness

Answer 17

get new islands(either found or created) and measure the way species repopulate the islands.

Question 18

give reasons why we find higher richness at tropical latitudes

Answer 18

tropics are older and disturbed less frequently,
(even though low disturbance should mean low diversity because one species would be able to dominate but high disturbance would wipe out everything)

tropics are more productive- there is so much energy that there is specuelized consumers and larger population of each and larger population means less extinction, (even though the more fertilization (from more energy and nutrients) means less diversity because one species would be able to out compete the rest of the species when nutrients arent a need anymore)

are also more stable and favorable, have uniform temperatures, precipitation and more land mass

Question 20

describe how el nino southern oscillation inluences global climate and productivity

Answer 20

since its the movement of heat=the movement of precipitation, the different areas it affects see a difference in plant growth or

significantly impacts global climate and productivity by causing large-scale changes in sea surface temperatures and atmospheric circulation patterns across the tropical Pacific Ocean, leading to altered precipitation patterns in various regions around the world, affecting agricultural yields, marine ecosystems, and extreme weather events like droughts and floods depending on whether it’s in an El Niño or La Niña phase; essentially, warmer waters during El Niño disrupt the typical upwelling of nutrient-rich cold water, impacting marine life and fisheries, while La Niña brings cooler waters and stronger trade winds, causing contrasting weather patterns

Question 21

describe predicted effects of increasing N fixation

Answer 21

increase fertilization can decrease diversity which changes ecosystems and eventually climate change due to difference in carbon absorbtion

Question 22

give evidence for linnks betwwen humanity activityy and increasing atmosphereic CO2