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68 Cards in this Set
- Front
- Back
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How is species diversity organized?
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On a hierarchy of spatial scales
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Define Local diversity
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The number of species in a small area of homogeneous habitat
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Define Beta diversity
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beta diversity compares different habitats to see how they differ in terms of species
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Define gamma diversity
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Number of species in all habitats of a region that lacks dispersal barriers
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What is the formula for alpha diversity
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species/habitat
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What is the formula for Beta diversity?
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(# habitats)/(average number of habitats per species)
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On a global scale, species richness is determined by ________________
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the balance between speciation and extinction
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What caused episodes of mass extinction?
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1. Catastrophe
2. Fragmentation 3. Rapid changes in global climate 4. evolutionary innovation by predators |
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As diversity increases, speciation ______________
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rate decreases until it matches extinction rate and an equilibrium is established
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What caused the really high plateau of diversity during mesozoic and cenozoic?
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The separation of the continents
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What are the 6 major terrestrial bioregions?
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1. Nearctic
2. Neo-tropical 3. Ethiopian 4. Oriental 5. Palearctic 6. Australian |
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What is phenotypic convergence?
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Two unrelated species have the same phenotype/morphology due to having similar environmental pressures
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What is a niche
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The role a species plays in its habitat; its actions and tolerated environments
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What factors support regional diversity?
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1. Topographic heterogeneity
2. Productivity 3. disturbance history and subsequent recolonization (good and bad dispersers) |
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What factors affect local diversity?
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1. species in a local area reflects composition of species in region
2. Time vs. dispersal 3. environmental heterogeneity 4. island biogeography 5. species sorting |
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What two things are being balanced in local diversity?
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colonization and extinction
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What is the effect of island size?
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Bigger island = higher colonization rate & lower extinction rate. it can support more species than small island
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What is the effect of island distance?
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Closer islands = more colonization
Farther islands = less colonization. Closer islands have more species than farther islands |
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What is species sorting?
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There are a limited number of niches in the environment. No two species can occupy the same niche for an unlimited amount of time. Eventually one will outcompete the other. In this way, nature "sorts" species into different niches until the niches are filled.
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What is the primary source of species diversity?
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Adaptive radiation
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What two processes lead to adaptive radiation?
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Adaptation to heterogeneous environments
Reproductive isolation |
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What is the formula for exponential growth?
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Nt = N0 e ^(rt)
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What is the formula for geometric growth?
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Nt = N0 (lambda)^t
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What is the formula for Lambda (just one time period)
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Lambda = Nt / Nt-1
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What kind of selection does spatial environmental heterogeneity lead to?
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Disruptive selection
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to survive, grow, and reproduce, what does an organism need?
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1. Materials
2. Energy to fuel metabolism, activity, and growth 3. An external environment to maintain its internal environment in homeostasis |
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What does an organism need in order to be fit?
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1. Maintain its body
2. Grow to sexual maturity 3. Reproduce |
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What determines rate of resource uptake?
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1. Resource availability in environment
2. phenotype of the organism 3. Availability of other resources |
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What are the four steps of resource allocation/
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1. Maintenance
2. Growth 3. Activity 4. Reproduction |
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What factors contribute to a heat budget?
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Metabolic heat, radiant heat, convective heat, conductive heat, evaporative heat.
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What are the heat capacities of the 3 earth compartments?
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atmosphere = low
hydrosphere = high geosphere = intermediate |
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Usable mineral nutrients of the 3 earth compartments?
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atmosphere = none
hydrosphere = variable geosphere = high |
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Physical phases of the 3 earth compartments?
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atmosphere = gas, aerosols
hydrosphere = liquid, dissolved gases geosphere = solid, liquid, gas |
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Light penetration of the 3 earth phases?
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atmosphere =high
hydrosphere = low geosphere =nil |
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usable water of the 3 earth compartments
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atmosphere =none
hydrosphere = high geosphere = variable |
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Co2 and O2 of the 3 earth compartments
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atmosphere = lots
hydrosphere = less at depth geosphere = variable |
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What is the seasonal turnover cycle in lakes?
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Summer: Thermal stratification; precludes mixing of top and lower layers
Fall: Winds mix layers Winter: ice forms on top of the lake, allowing water to remain underneath Spring: winds mix layers |
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What are the horizons of soil?
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O = organic litter
A = chemically altered rock, humus B = Less- weathered rock C = Parent material, redeposited salts leached from upper horizon |
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What is soil?
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Soil is broken down and chemically reconstituted rock
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What is climate?
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The predictable annual variation in temperature and precipitation in an area
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What causes gradients/variation in temperature?
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Latitude
Elevation Coast vs. inland |
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What causes gradients/variation in precipitation?
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latitude
elevation coast-inland ENSO |
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What stresses organisms?
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High and low water
High and low temperatures |
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How do orgs maintain homeostasis in the midst of nonideal temperature?
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1. Behavioral, morphological, physiological mechanisms that alter heat exchange
2. Physiological tolerance of the nonideal temperature |
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How do plants increase heat loss?
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1. Increase surface:volume ratio
2. Decrease boundary layer 3. make leaves smaller |
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What are the general methods of dealing with hot temperatures?
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1. reduce radiation from sun
2. increase heat loss through bigger SA:V ratio, thinner boundary layer, increase evaporative loss 3. Have physiological proteins and cell membranes that can stand that temperature |
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What are the general methods of dealing with cold temperatures?
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1. increase exposure to radiation from sun
2. decrease heat loss through decreased SA:V ratio, increased boundary layer, decreased evaporation, counter-current circulation 3.Physiological tolerance of cell membranes and enzymes to low temperature |
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how is water uptake done in plants?
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Via aquaporins in cell membranes of the root
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Why do flooded plants get in trouble?
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Not enough oxygen getting into the roots to power the active transport mechanism of aquaporins
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What factors does the rate of water loss depend on?
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1. Surface area of evaporation
2. Vapor pressure difference between leaf and air 3. Width of boundary layer --> this affects rate of water diffusion |
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Why is C3 not water efficient?
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It binds CO2 poorly and stomates have to be open longer to gather enough CO2. It uses RuBP carboxylase. This means there is always a high CO2 concentration in the mesophyll and thus diffusion into the mesophyll by CO2 is slow.
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Why is C4 water efficient?
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C4 uses the enzyme PEP carboxylase which binds CO2 more efficiently, allowing CO2 to enter the mesophyll faster. Also, bound CO2 (now part of OAA) is transported to a different compartment, which increases the diffusion of CO2 into the mesophyll. Stomates can be open a shorter time, reducing water loss.
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Why is CAM water efficient?
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CAM separates the Calvin-Benson cycle by time. The carbon-fixing part of it is done at night when temperatures are lower and evaporation rates will be lower. The other parts of the calvin benson are done during the day.
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How do animals change their uptake and loss to conserve water?
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Water intake: ingestion, metabolic water
Water loss: evaporation during gas exchange. Excretion of nitrogenous wastes. |
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Examples of animal adaptations for water loss?
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impermeable skin
behavior - seek shade efficient kidneys breathing to recover water high carbohydrate diet |
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What factors are necessary for an individual to successfully respond to environmental variability?
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1. Envrionmental Signal
2. Signal reception 3. Signal transduction 4. Activation of behavioral or phenotypic response |
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what are examples of individual response - behavior?
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1. prey or patch selection
2. Microhabitat selection 3. migration 4. food storage, dormancy |
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What are examples of plant phenotypic plasticity?
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1. stem elongation of plants in low light
2. hair leaves are low in summer time, allowing greater absorption of sunlight |
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what are examples of animal phenotypic plasticity?
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grasshoppers that change color by seasonal environment color change
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What are two examples of fixed life history adaptations?
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semelparous - breed once and die
ephemeral life history - short life history of 6 weeks or so. |
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What causes seasonal variation in climate?
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the tilt of the earth's axis
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What causes hadley cells?
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Since the earth is tilted and spherical, there is differential warming of the earth's surface. The equator is exposed to the most heat, so air rises from that air preferentially. As it rises, it loses its capacity to hold moisture. Rain falls. The air continues both north and southward from the equator. It eventually cools and falls on 30d north and south of the equator. Since it has lost all its moisture, it is very dry.
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What biomes and climates are associated?
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tropical rain forest - equatorial
tropical seasonal forest - tropical subtropical desert - subtropical Woodland/shrubland - Mediterranean Temperature rain forest - Warm temperate Temperate grassland - Continental Boreal forest - Boreal Tundra - Polar |
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What is the river continuum concept?
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heading downstream, water flows slower and becomes warmer and richer in nutrients.
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How are freshwater lakes structured?
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With zones. Structural heterogeneity reflects temperature productivity and light exposure.
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what is the fundamental niche?
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describes how fitness of individual organisms varies with environmental conditions.
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what does high allocation to roots mean?
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low productivity, high levels of light (or not light limited), and usually shorter plants.
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what does high allocation to shoots mean?
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high productivity, low levels of light, and usually taller plants.
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