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Describe the invasion process
- transport and introduction
- establishment in the recipient region
- range expansion
What are the characteristic of non-indigenous species?
- widespread with high abundance
- widespread with low abundance
- restricted range with high local abundance
- restricted range with low local abundance
What kind of barriers do invasive species have to encounter?
- geographical barriers
- physiological barriers
- demographic barriers (early effects, biotic interactions)
How are invasive species transported and introduced?
- ballast water (unintentional transport)
- food, recreation, etc (intentional transport)
In an ecosystem, what is the relationship between native species richness and probability of establishment? Explain.
- more diverse ecosystem, more resistance to invasion -> fewer niches and resources available
- more diverse ecosystem, less resistant to invasion -> what drives the increase in species richness in native species works the same way for invasive species
Provide an example of how establishment may be naturally facilitated.
- Zebra mussels ...
- high filtering rate has large impact on native plankton communities
- --> increase water clearity, microphytes flourish
- --> increase organic matter and provide substrate for benthic macroinvertebrates
- allows for both native and non native species to flourish
What does geographic spread depend on?
population growth and dispersal ability
Describe the phosphorus cycle.
- largest quantities of P occur in mineral deposits and marine sediments
- P is slowly released through the weathering of rock
- P is absorbed by plants, moves through the food chain and decay eventually returns P to the environment
- Much P ends up dissolved in oceans
- P returns to terrestrial system through uplift of marine sedimentary rock
Describe the nitrogen cycle.
- atmospheric pool of N in the form of N2
- N fixation- N2 is reduced into NH3 by N fixers, lightening, and burning of fossil fuels for human use
- ammonification after an organism dies
- nitrification by bacteria
What can we say about the relationship between biodiversity and ecosystem functioning?
- biodiversity loss reduced efficiency by which communities capture resources, produce biomass, decompose, and recycle nutrients
- biodiversity increases stability of ecosystem through time
- the impact of biodiversity is non-linear and saturating
- diverse communities are more productive because...
- ...key species with large influence on productivity
- ...differences in functional traits increase total resource capture
- loss of diversity across trophic levels may have stronger influence then within trophic levels
- function traits of organisms have large impact on magnitude of ecosystem function
What are the factors that influence biodiversity?
- abiotic environment
- species interactions
- spatial heterogeneity
- migration of individuals
Describe the carbon cycle.
- plants absorb CO2 from the atmosphere during photosynthesis
- release CO2 during respiration
- dissolved CO2 in oceans used by marine
- fossil fuels and changing land use also contribute
- the ocean sink is growing, but the atmosphere sink is shrinking
- carbon in soils, peat, fossil fuels and carbonate rock take a long time to return back to the atmosphere
- largest pool of carbon is contained in carbonate rocks
What is the difference between a heterotroph and an autotroph?
- heterotroph: consumes organic molecules from other organisms
- autotroph: assimilates inorganic resources and produces organic molecules (use energy from sun or other chemical reactions), increases with increasing nutrient addition
What evidence is there for hetertrophy in lakes?
- many lakes are supersaturated with CO2bacteria metabolize dissolved organic carbon
What are the different kinds of competition?
- intra-specific competition: among individuals within a species
- inter-specific competition: among individuals of different species
- direct competition:
- indirect ccompetition: Through a shared limiting resource
- interference (contest) competition: direct interaction among species
- exploitative (scramble) competition:
- apparent competition: indirect competition through a shared predator
What is the difference between fundamental niche and realized niche?
- fundamental niche: range of biotic and abiotic conditions and resources that a species can persist in the absence of interactions with other species
- realized niche: range of biotic and abiotic conditions and resources that a species can persist in the presence of interactions with other species
What is environmental heterogeneity? How can it be classified?
- the number of species in a given area can often be greater in heterogeneous environments.
- extrinsic heterogeneity: heterogeneity is a feature of the environment
- intrinsic heterogeneity: heterogeneity is caused by the coupled action of environment and the community (eg nutrients)
What is the intermediate disturbance hypothesis?
- natural systems often experience disturbance
- low disturbance means high competition
- high disturbance- few species with the appropriate fundamental niche
- intermediate disturbance has greater diversity
Describe the equilibrium model of island biogeography.
- on the x axis you have # of species present
- on the y axis you have rate of immigration or extinction
- the rate of immigration of new species decreases as the number of species on the island increases, the opposite is true for the rate of extinction
- higher rate of immigration for islands near a source of colonists
- higher rates of extinction on small islands
How might biodiverisity influence ecosystem function?
- sampling effect
How might nutrients change as a result of succession?
- decrease in soil P: primary source of P is the weathered bedrock, over time it becomes less accessible and the demand for phosphorus increases so the concentration in the soil decreases
- increase in soil N: more N fixers as succession progresses, and as the soil depth increases, increase in N retention b/c N binds well to soil particles and doesn't get washed away by water
What kind of physiological and life history traits differ from early to late succession?
- respiration rate- EARLY-high LATE-low
- seeds- EARLY- many, small, LATE- few seeds, large
- transpiration rate- EARLY- high, LATE- low
- growth rate- EARLY- rapid LATE- slow
- mature size- EARLY- small LATE- large
Why do species differ in their elemental ratios?
- organic molecules that make them up differ in their elemental composition
- species differ in their relative composition of the organic molecules
How do nutrient ratios differ in terrestrial and aquatic organisms?
terrestrial- more variation in C:N ratios
What are the different metacommunity paradigms?
- patch-dynamics: patches are identical, A is a better competitor, B is a better disperser, coexistence in region
- species sorting: A is a better competitor in one environment, B is a better disperser in another
- mass-effects: same as above, dispersal very high
- neutral: all species are similar, movement is random
What are some important steps in the N cycle?
- nitrification: the conversion of ammonia to nitrate, generally mediated by bacteria
- immobilization: the conversion of inorganic ions (eg nitrate) into organic compounds
- mineralization: the breakdown of organic matter from organic to inorganic for during decomposition
How is the N cycle affected by temperature and moisture?
- microbial activity increases with increasing temperature
- decomposition increases with increasing moisture
- N cycle also affected by...
- substrate physical and chemical properties
- microbial biomass size
- shoot sink strength
What are some effects the tar sands are having on water?
- water becomes highly contaminated
- migratory waterfowl die by inadvertently landing in the ponds each year
- causes deformaties on fish and increases mortality
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