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2012-03-20 02:11:54

Ecology Exam 2 2.0
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  1. Autotroph
    An organism capable of developing organic molecules from simple inorganic molecules using either chemical or light energy
  2. Heterotroph
    An organism that cannot fix carbon and therefore must obtain organic molecules from other eating organisms
  3. Photosynthesis
    a chemical process that converts carbon dioxide and water into organic compounds, especially sugars, using light energy
  4. Respiration
    • metabolic assimilation of oxygen, accompanied by breakdown of organic compounds, release of energy, and production of carbon dioxide
    • and water
  5. Net Photosynthesis
    photosynthesis – respiration; units are moles CO2 per unit leaf area per unit time
  6. Light Compensation Point
    light level (value of PAR) at which photosynthesis and respiration balance each other
  7. Light Saturation Point
    light level at which maximum photosynthesis is achieved
  8. Stomata
    pores in the leaf or stem of a plant that allow gaseous exchange between the internal tissues and the environment
  9. Water Use Efficiency
    ratio of carbon fixed (photosynthesis) per unit of water lost (transpiration); Has important implications for where different types of plants are found
  10. Light reactions
    the capture of light energy during photosynthesis; results in the synthesis of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate)
  11. Dark reactions
    the biochemical incorporation of CO2 into simple sugars; do not require the presence of sunlight, but are dependent on the products of the light reactions (ATP and NADPH)
  12. Temperature
    a measure of the quantity of thermal energy in an object
  13. Heat
    thermal energy in transit from a high-temperature object to a low-temperature object
  14. Radiation
    transfer of heat by electromagnetic waves
  15. Conduction
    transfer of heat from molecules of one substance to another
  16. Convection
    transfer of heat by the movement of a liquid or gas
  17. Evaporation/Condensation
    transfer of energy required to initiate phase change from a liquid to a gas or a gas to a liquid
  18. Why are leaves green?
    The combination of visible light wavelengths absorbed by the combination of pigments present in the leaf (i.e. chlorophyll) allow for the overall reflection of green light
  19. C3 Photosynthesis
    • CO2 is captured by rubisco and converted into a three-carbon molecule (phosphoglycerate; 3PGA)
    • -Rubisco has low affinity for CO2 and favors oxygenation over carboxylation at low CO2 concentrations and warm temperatures
    • -most common where temperatures are cooler or water availability is high
  20. C4 Photosynthesis
    • CO2 is captured by PEP carboxylase and converted into a four-carbon acid (oxaloacetate; OAA)
    • -Unlike rubisco, PEP carboxylase has high affinity for CO2 and does not catalyze photorespiration
    • -Depends on specialized leaf anatomy; rubisco is found only in cells that are spatially segregated from external air
    • -favored under warmer and drier conditions
  21. Crassulacean Acid Metabolism (CAM)
    • uses essentially the same biochemistry as C4 photosynthesis to overcome the limitations of rubisco and eliminate photorespiration
    • -Instead of using spatial separation, capture of light energy and uptake of CO2 is separated temporally
    • -most closely associated with highly arid temperate regions
  22. How and why does photosynthetic rate vary with light availability?
    The less light, the less photosynthesis. The light level must be above the Light Compensation Point (LCP) for the carbon uptake to exceed the carbon loss in respiration. But it is also possible for photosynthesis to become light saturated, at values of PAR above the Light Saturation Point, whereupon it maxes out. However some plants extremely adapted to shady environments may experience photoinhibition, where overbearing light causes photosynthetic rates to decline as well.
  23. Describe the movement of water between soils, plants, and air and the common mechanism driving this movement
    • Water moves from larger to smaller values of water potential.
    • Water loss through transpiration continues as long as (1) the amount of energy striking the leaves is enough to promote evaporation; (2) moisture is available for roots in the soil, and (3) roots are capable of maintaining a more negative water potential than that of the soil.
  24. Water potential (ψ)
    the difference in potential energy between pure water (which is defined as having a water potential of zero) and the water in some system, such as in a plant cell or in the soil
  25. Osmotic potential (ψπ)
    due to differences in concentration of dissolved solutes (zero or negative)
  26. Pressure potential (ψp)
    due to differential hydrostatic or pneumatic pressure in the system (positive or negative)
  27. Matric potential (ψm)
    due to the cohesive force that binds water to physical objects (negative)
  28. Gravitational potential (ψm)
    due to the pull of gravity on water (negative)
  29. The trade-offs associated with each of the three types of photosynthesis and how climate change might influence global patterns of photosynthesis as a consequence
    • At temperatures below 25 °C rubisco operates quite well; the C4 system operates best at ~45 °C
    • C4 plants must expend energy to regenerate PEP, a disadvantage at low light levels
    • Photosynthesis evolved under high levels of CO2 where the advantages of the C4 pathway would be reduced
    • While temporal separation of C3 and C4 reactions in CAM plants limits maximum photosynthetic rates, water use efficiency is maximized
  30. Herbivore
    animals feeding exclusively on plant tissue
  31. Homeotherm
    organisms who maintain relatively stable body temperatures (an example of homeostasis); warm-blooded; generally endothermic
  32. Carnivore
    animals who feed exclusively on animal tissue
  33. Poikilotherm
    organisms whose body temperature changes in concert with external conditions (cold-blooded); generally ectothermic
  34. Omnivore
    animals feeding on both plants and animal tissues
  35. Heterotherm
    An organism whose ability to regulate its body temperature is intermediate between an endotherm and an ectotherm. Some small birds and mammals – generally endothermic (‘warm-blooded’) groups – may reduce their metabolic rate during a particular season or even a certain time of day, allowing their body temperature to fall and entering a state of torpor. At the opposite end of the spectrum, certain animals that are generally regarded as ectothermic (‘cold-blooded’) have the ability to generate heat internally for limited periods.
  36. Detritivore
    animals that feed on dead plant and animal matter
  37. Torpor
    a temporary state of reduced metabolic rate
  38. Nutrient
    substance an organism requires for normal growth and activity
  39. Thermoneutral Zone
    range of environmental temperatures within which metabolic rates are minimal
  40. Essential Nutrient
    a nutrient which cannot be synthesized by a given organisms; must be supplied by the diet
  41. Countercurrent Exchange
    an anatomical and physiological arrangement by which exchange of energy or matter takes place between arterial and veneous blood moving in opposite directions
  42. Homeostasis
    An organisms regulation of internal conditions such that a balance of said conditions is always maintained within a normal range
  43. Endotherm
    organisms who rely on internal (metabolic) heat production to maintain relatively high body temperatures
  44. Ectotherm
    organisms whose body temperatures are determined primarily by external thermal conditions (variable)
  45. The difference between isometric and allometric scaling
    • Relationships between length and surface area or volume are constant as size changes
    • in isometric scaling whereas in allometric scaling the relationships change.
  46. How surface area/volume ratios change with increasing size of an object and why that might matter for living organisms
    • When an object increases in size, its surface area increases, however it decreases with respect to volume. This relationship places a critical constraint on the evolution of animals; for example, as most every animal (Loriciferans being exceptions) depends on oxygen to survive, this causes the diffusion of oxygen from the external environment through to the interior tissues to increase in difficulty with an increase in body size. Animals could not get very large at all by way of diffusion alone for oxygen transport. This has allowed for the development of wrinkled surfaces on organisms to increase surface area, and/or elaborate active transport systems for oxygen into the body's interior.
    • Especially concerned is the relative heat loss which increases with decreasing size for endotherms; this must be offset by increased metabolic activity. Ectotherms have decreasing relative heat gain from their environments with increasing size; therefore large ectotherms are restricted to warmer environments
  47. Herbivory (Digestive)
    Developed specialized digestive systems with which they may digest their diets rich in cellulose. Many depend on the presence of microorganisms bacteria/protozoa in their DT for the digestion of cellulose. Some even eat what they regurgitate or defecate for additional digestive purposes.
  48. Grazers feed on
    leafy material
  49. Browsers feed on
    woody material
  50. Granivores feed on
  51. Frugivores feed on
  52. Nectivores feed on
  53. Carnivory (digestive)
    simple stomachs and short intestines; eating animals (herbivores)
  54. Omnivory
    feeding on both plants and animals
  55. Detritivory
    feeding on dead plant and animal matter
  56. The major pathways through which organisms gain and lose heat
    • Changes in metabolic rate
    • Heat exchange
  57. The potential adaptive advantages of acclimatization
  58. How homeothermic ectotherms are able to regulate their body temperature
    They might sun themselves when it is cool, seek shade and moisture, and be more still when it is warm
  59. How organismal performance typically relates to temperature and what happens physiologically at extreme temperatures
    • Poikilotherms respond to increasing temperature with a standard performance curve that increases to a maximum before declining sharply
    • Cannot be active at extreme temperature
    • Homeotherms may shiver when cold or sweat when warm.
  60. How width of the thermal neutral zone among species varies with latitude and why
    The width of the thermal neutral zone is greater for species closer to the poles due to the fact that they are subjected to much lower temperatures and have evolved such that they maintain their constant metabolic rate over a broader ranger. If Arctic animals were going to shiver in the cold, they wouldn't live in the Arctic!
  61. Trade-offs between endothermy and ectothermy
    • Endothermy
    • -Animals can remain active regardless of environmental temperatures
    • -Energetic demands are very high; limits allocation of resources to growth and reproduction
    • Ectothermy
    • -Energetic demands are often low; increases allocation of resources to growth and reproduction
    • -Animals are often inactive due to environmental temperatures
  62. How a countercurrent exchange system works
    An anatomical and physiological arrangement by which exchange of energy or matter takes place between arterial and veneous blood moving in opposite directions, a countercurrent exchange system may work by surrounding cooler veins with warmer arteries in the extremities to warm the blood being returned to the body and minimize heat loss.
  63. Life History
    an organism’s lifetime pattern of growth, development, and reproduction
  64. Hermaphrodite (Animal)
    an individual that posses both male and female sexual organs (testes and ovaries)
  65. Simultaneous Hermaphrodite
    individuals that posses both male and female sexual organs at the same time in its life cycle
  66. Sequential Hermaphrodite:
    individuals that change sex at some point during its life cycle
  67. Principle of Allocation
    if organisms use energy for one function such as growth, the amount of energy available for other functions is reduced
  68. Mating System
    describes the pattern of mating between males and females in a population
  69. Monogamy
    males and females form a lasting pair bond, mating with only one member of the opposite sex
  70. Promiscuity
    individuals form no pair bond and mate with more than one member of the opposite sex
  71. Polygamy
    acquisition by an individual of tow or more mates; a pair bond exists between the individual and each mate
  72. Asexual reproduction
    any form of reproduction that does not involve the fusion of gametes
  73. Sexual Selection
    differential mating success among individuals as a result of competition for access to mates; male-male combat (intrasexual) and female choice (intersexual)
  74. Parthenogenesis
    development of an individual from an egg that did not undergo fertilization
  75. Sexual reproduction
    any form of reproduction that involves the fusion of haploid gametes (egg and sperm) into a diploid zygote
  76. Dioecious
    plants with male and female reproductive organs on separate individuals
  77. Hermaphrodite (Plant)
    plants with both male and female reproductive organs within the same floral structure
  78. Monoecious
    plants with male and female reproductive organs in separate floral structures on the same individual
  79. Advantages and disadvantages to asexual reproduction
    • Advantages – local adaptation and high population growth rate
    • Disadvantages– low genetic variability and consequent inability to respond effectively to natural selection
  80. Common life history trade-offs relating to reproduction
    • Individuals produce either many small eggs or few large eggs
    • Smaller individuals produce fewer eggs
    • Larger seeds often lead to fewer seeds but greater seedling success
  81. How individual energy budgets typically change after organisms meet sexual maturity
    • Before – energy goes to maintenance or growth
    • After – energy goes to maintenance, growth, and reproduction
    • Individuals delaying reproduction should grow faster and reach a larger size, resulting in increased fecundity
  82. Intrinsic rate of increase, rmax; r versus K selected species
    • r selection: High
    • K selection: Low
  83. Competitive ability; r versus K selected species
    • r selection: Not strongly favored
    • K selection: Highly favored
  84. Development; r versus K selected species
    • r selection: Rapid
    • K selection: Slow
  85. Body size; r versus K selected species
    • r selection: Small
    • K selection: Large
  86. Reproduction; r versus K selected species
    • r selection: Early; single, semelparity
    • K selection: Late; Repeated, iteroparity
  87. Offspring; r versus K selected species
    • r selection: Many, small
    • K selection: Few, large
  88. Population
    a group of individuals of the same species living in a given area at a given time
  89. Random
    • distribution lacking pattern or order; placement of each individual is independent of all other individuals
    • -Uniform distribution of resources
    • -Neutral interactions among individuals
  90. Genet
    a genetic individual that arises from a single fertilized egg
  91. Regular
    • distribution in which individuals are more uniformly placed than would be expected by chance
    • -Local depletion of resources
    • -Negative interactions among individuals
  92. Ramet
    clone; a module produced asexually and a potentially physiologically independent unit
  93. Clumped
    • distribution in which individuals have a much higher probability of being found in some places than in others
    • -Patchy resource distribution
    • -Positive interactions among individuals
  94. Metapopulation
    a population composed of subpopulations held together by movements of individuals among them
  95. Dispersal
    leaving an area of birth or activity for another area
  96. Abundance
    • the number of individuals in a population (N)
    • Determined by:
    • the area over which the population is distributed
    • & the population density
  97. Migration
    intentional, directional, usually seasonal movement of animals between two regions or habitats; involves departure and return of the same individual
  98. Density
    number of individuals per unit area
  99. How the concepts of genet and ramet relate to counting individuals in a population
    though genets and ramets exist as two distinct levels of population structures, for practical purposes, ramets are counted as (and function as) individual members of a population
  100. The relationship between body size and population density for animals and plants
  101. How to interpret a mean/variance ratio in the context of evaluating the spatial distribution of individuals within a population
  102. The typical pattern of spatial distribution of organisms at large scales and the ecological factors that might generate such a pattern
  103. The seven forms of rarity
  104. The importance of dispersal
  105. How one might estimate the abundance and density of an organism and why you would want to do this
  106. Intrinsic Rate of Increase (r)
    describes the ability of an individual to survive and reproduce in a given environment
  107. Finite Rate of Increase (λ)
    • the proportional change in population size from one year to the next (λ = Nt+1/Nt);
    • the average number of offspring produced by an individual per generation
  108. Life Table (Cohort and Time-Specific)
    tabulation of age-specific mortality and survival
  109. Net Reproductive Rate
    average number of female offspring produced by a female during her lifetime
  110. Stable Age Distribution
    constant proportion of individuals of various age classes within a population through time
  111. What a model is and why we use models to study populations
    • Model:a description of a natural phenomenon
    • They are simplifying and helpful for identifying important factors to study
    • They generate testable hypotheses (highlighting distinctions between patterns and mechanisms
    • Identification of the models assumptions may explain when predictions don't match observations
  112. The factors that contribute to changes in population size
    birth rates and death rates
  113. What we mean when we say a population is growing exponentially and how the value of r relates
    to changes in population size
  114. The basic assumptions of the simple exponential model of population growth and whether these
    assumptions are ever met in the real world
  115. How geometric population growth differs from exponential growth and the types of organisms for which a geometric model would be most appropriate
  116. How to calculate the finite rate of increase (λ)
  117. What the age distribution of a population can tell us about potential future population dynamics
  118. How to calculate the different values in a life table and what each represents
  119. How to identify and interpret the three types of survivorship curves
  120. The importance of the stable age-distribution in the context of interpreting the output from a population projection table
  121. The relationship between r and λ
  122. Carrying Capacity (K)
    population density where b = d and population growth is zero
  123. Density-Dependent effects
    • – population growth slows due to interactions among organisms (e.g., competition, aggression, disease) in proportion to population size; implies feedbacks
    • Mortality rate increases (density-dependent mortality)
    • Fecundity rate decreases (density-dependent fecundity)
    • -implies feedbacks
  124. Independent Population Growth
    • population growth limited by environmental factors (e.g., temperature, fire, wind) regardless of population size
    • -no feedbacks
  125. Allee Effect
    when reproduction and/or survival decrease with decreasing population density, in contrast to the general expectation
  126. Competition
    any interaction that leads to reduced survival, growth or reproduction due to shared requirements for limited resources; an interaction that is mutually detrimental to both participants (-/-)
  127. Scramble Competition
    when limited resources are shared to the point that no individual survives
  128. Contest Competition
    when limited resources are shared only by dominant individuals; a relatively constant number of individuals survive
  129. Exploitative Competition
    operates indirectly by the depletion of some shared resource
  130. Interference Competition
    involves direct interactions among competitors
  131. How demographic parameters (i.e., survival, growth, and reproduction) are expected to change with increasing population size and why
  132. The relationship between exponential and logistic population growth
  133. How the value of r changes as population size approaches (or surpasses) carrying capacity
  134. Potential mechanisms that might lead to an Allee effect
  135. Why the Allee effect is considered to be potentially important for endangered species conservation
  136. How the rate of change in population size (dN/dt) changes as a function of population size
  137. The two conditions necessary for competition to occur
  138. How density-dependent and density-independent factors might limit population size
  139. Metapopulation
    set of (local) subpopulations held together by dispersal or movements of individuals among them
  140. Habitat Patch
    discrete area of suitable habitat (place where an organism lives) within a larger landscape of unsuitable habitat
  141. Environmental Stochasticity
    random variations in the environment that directly affect birth and death rates
  142. Rescue Effect
    increase in population size (and decrease in extinction risk) that occurs with an increasing rate of immigration
  143. Mainland-Island Metapopulation Model
    a single habitat patch (the mainland) is the dominant source of individuals to island populations
  144. What are the four conditions necessary to have a metapopulation?
    • Suitable habitat occurs in discrete patches that may be occupied by local breeding populations
    • Even largest populations have a substantial risk of extinction
    • Habitat patches must not be too isolated to prevent recolonization after local extinction
    • Dynamics of local populations are not synchronized
  145. How is patch occupancy in a metapopulation related to local extinction and recolonization rates?
  146. How are local extinction and recolonization rates related to patch size and isolation (interpatch distance)?
    • Increased isolation, decreased recolonization rates
    • Increased patch size, decreased local extinction
  147. How does habitat heterogeneity influence metapopulation persistence?
    • Decreases risk of local extinction as greater habitat heterogeneity reduces the impact of environmental stochasticity
    • (random variations in the environment that directly affect birth and death rates)
  148. What is the difference between source and sink habitats and the potential implications of that difference for conservation?
  149. How might local population dynamics become synchronized and what are the potential effects on metapopulation persistence?
    • through regional environmental stochasticity (i.e., weather) or long-term landscape and habitat changes
    • If synchronized, this makes the metapopulation more vulnerable