Exam 3

• What is the clements models of succession?

  A grand organizing force behind succession with each step being taken toward the ‘perfect’ community believed in a monoclimax community; that succession had only 1 endpoint.
• Climax community

  final step in succession, a community that is stable and can maintain itself indefinitely (if no disturbance)
• What is the gleason models of succession?

  changes in community composition were not the result of a grand organizing scheme rather, were affected by the abilities and tolerances of individual species.

  Successional stages (associations of plants) were merely the result of a set of species being somewhat adapted to similar conditions.
• What would Clements predict? What would Gleason?

  Clements: there are 2 states (red and blue critters and yellow and black critters

  Gleason: there is a gradual change from red-blue organisms to yellow-black organisms

  
• Describe Similarity/Dissimilarity in Clementsonian Model and Gleasonian Model:

  Clementsonian: Random samples of organisms are normally very similar or quite different

  Gleasonian: Random samples have no dominant composition; many intermediate or mixed
• Describe Continuity in Clementsonian Model and Gleasonian Model:

  Clementsonian: Associations of organisms have sharp boundaries with discrete boundaries

  Gleasonian: Boundaries not sharp; different associations grade into one another
• Describe Association in Clementsonian Model and Gleasonian Model:

  Clementsonian: Particular groups of species tend to co-occur

  Gleasonian: No consistent species associations
• Describe Interaction strength in Clementsonian Model and Gleasonian Model:

  Clementsonian: Strong interactions between organism

  Gleasonian: Weak interactions between organisms
• What are the 6 mechanisms than can cause diversity gradients?

  1. Evolutionary speed

  2. Geographic area

  3. Interspecific interactions

  4. Ambient energy

  5. Productivity

  6. Disturbance
• How can evolutionary speed cause diversity gradients?

  Some areas may have higher specieation and/or lower extinction rates and/or may have more time since extinction so accumulation.
• How can geographic area cause diversity gradients?

  larger areas support more species than smaller habitats
• How can Interspecific interactions cause diversity gradients?

  Competition, predation, and facilitation
• How can Ambient energy cause diversity gradients?

  Available energy generates and maintains species richness gradients. Climate determines energy available.
• How can Productivity cause diversity gradients?

  more energy input, more productivity, more resources, more diversity
• How can Disturbance cause diversity gradients?

  Intermediate disturbance hypothesis (IDH) – medium levels of disturbance allows maximal diversity within a community
• How would you find the beta level of a biodiversity table?

  Find the sum of each species
• What is the Simpson’s Index of diversity?

  D= Sum(pi^2)
• What is the Shannon-Wiener index?

  H' = -(sum(pi*log2(pi)))
• What is C3, C4, and CAM?

  C3: light harvesting and glucose synthesis sites are in the same area (higher C02)

  C4: plants separates light harvesting and glucose synthesis phases (high temps)

  CAM: C4 is initial step but collects CO2 during night and makes glucose in the day (high stress)
• What is the Pyramid of Numbers?

  If you graph the abundance of organisms vs. their size, in higher trophic levels the abundance decreases and the body size increases.
• Why might certain ecosystems (such as pelagic marine food webs) have inverted pyramids?

  Primary producers are large or have less biomass
• Turnover rate

  Appearance or extinction of species in an ecosystem
• What are the three ways to measure community productivity?

  1. Biomass: how much organic matter present; weight or standing crop of each species

  2. Flow of chemicals: tracking elemental cycling through trophic levels

  3. Flow of energy: how much energy is transferred across trophic levels
• What factors influence plant efficiency in converting solar energy?

  Solar Constant

  Latitude

  Cloudiness

  Dust and water in atmosphere

  Leaf arrangement and leaf area

  Concentration of CO2
• Dynamic Stability Hypothesis

  long chains are more unstable
• Productivity Hypothesis


  longer chains in more productive environments
• Ecosystem Size Hypothesis

  longer chains in larger environments (independent of productivity)
• Productive Space Hypothesis

  Longer chains in larger and more productive environments (a combo)