Exam 1 Flashcards
Clements School of thought?
Clements had the organismal viewpoint. In which plant communities as complex organisms. Holism- Whole is more than the sum of its parts.
Gleasons School of thought?
Gleason- Individualistic viewpoint – plant communities are the occurrence of the individual physiological tolerances and vagaries of dispersal.
Explain the relationship among leaf-level photosynthesis, leaf N concentration & leaf longevity. What is the main physiological mechanism structuring this relationship?
The main physiological mechanism is construction reparation.
High photosynthesis ->high Rubisco/N -> high maintenance respiration -> low longevity
rubisco( enzyme) facilitates photosynthesis works harder and faster with more N. The more N added the higher rate of photosynthesis and respiration
What is Construction Respiration?
Respiration used for the biosynthesis of new organic compounds – fixe cost.
What is maintenance respiration?
Is a variable and is the energy used up to maintain the pathways, replacing proteins and replacing cell membrane. This can be influenced by the the environment.
Respiration used to repair proteins and membranes, maintain ionic gradients, uptake of nutrients
Why is the amount of ABOVE GROUND NPP poorly predicted from the immediate conditions in which plants are growing? Use a specific example and explain how this can occur and why it has ecosystem implications?
In perennial plants, storage decouples plants from the immediate environment. Antecedent years conditions influence belowground storage, which can be deployed the following year for aboveground growth (NPP).
Which type of respiration is most responsive to environmental factors? why is this so?
Maintenance respiration- for example as temp increase & N availability increases proteins are working harder and getting damaged which means that they have to be replaces faster which is a function of maintenance respiration.
responds to temperature and soil N availability. Increases with both
Compare & Contrast the types of defense compounds synthesized by SLOW GROWING vs. FAST GROWING plants?
Lignin – slow growing plants, immobile C-based defense, effective in high concentrations
Alkaloids – fast growing plants, mobile defense, N-based, effective in low concentrations
Why is the ratio of root biomass to shoot biomass a poor predictor of how plants alter belowground allocation in response to soil nutrient availability?
Standing crop of fine roots does not provide insight into the dynamics of root birth and death, different permutations of which can lead to a decline in the standing crop of roots as soil resources increases. This can occur by an increase, decrease or no change in belowground allocation, depending on the dynamics of root birth and death.
Explain how and why GPP, Ra, and NPP change during secondary succession? ( use your understanding of plant carbon balance)
Early in succession – GPP > Ra; biomass increases, NPP is > 0.
Late in succession – GPP ~ Ra; biomass in steady state, NPP~ 0
In secondary succession GPP is about the same as Ra and biomass is in a steady state so NPP is close to zero. Ra goes up and NPP down.
Identify and Explain underlying mechanisms that allow us to predict above ground NPP with simple climatic Variables?
Temperature and AET can be used to predict spatial patterns of ANPP, because the latter approximates the amount of water plants have available transpiration. Plants must open stomates to fix CO2, and lose water at the same time.
Provide an example of how the life-history traits (physiological and developmental traits) of early successional plant species contribute to the resilience of NPP?
Fast-growing plants with buried seed banks, like pin cherry and aspen, can rapidly proliferate after a disturbance and increase NPP circumventing nutrient loss by rapid update to meet demand of NPP.
Explain the mechanism leading to phosphorus rentention and loss in these ecosystems and why Rainforest B contains more phosphorus than Rainforest A?
Nutrients are lost when NEP < 0; this occurs more frequently in forest A, when biomass goes to zero after a disturbance
In Rainforesst B, please explain the relationship between Net Pimary Prpductivity (NPP) and heterotrophic preparation (Rh) that occurs between 100 to 200 yrs?
NPP ~Rh Biomass is in steady-state.
Between the years 100-200 the rainforest is already maturing/ in secondary succession.
Explain how allocation to defense and soil nutrient availability interact to influence the chemistry of plant litter and the rate at which it is decomposed by heterotrophic microorganisms in soil.
Increased allocation to C-based defense, like lignin and tannins, slows decay, because these compounds contain very little energy for microbial growth.
