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89 Cards in this Set
- Front
- Back
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Regardless of an ecosystem's size, its dynamics involve what 2 main processes? |
Energy flows through chemical cycling (matter cycles within them) |
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What is the 1st law of thermodynamics? |
Energy in neither created or destroyed |
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What is the 2nd law of thermodynamics? |
Physical systems tend to proceed to a state of greater disorder (entropy) |
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Ecosystems are what type of ecosystems? |
Open, absorb energy and mass and release heat and waste products |
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Everyday, the earths atmosphere receives enough energy to supply all of humanities energy consumption for how many years? |
25 years |
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What percentage of solar energy that reaches the earth is converted o chemical energy by plants? |
1% |
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What is primary production? |
The amount of light energy converted to chemical energy by autotrophs during a given time period |
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T/F the extent of photosynthetic production sets the spending limit for a community's energy budget |
true |
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What is gross primary production? |
Total primary production |
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How is gross primary production measured? |
conversion of chemical energy from photosynthesis over time |
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What is net primary production? |
Gross primary production minus energy used by primary producers for respiration |
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What is net primary production expressed as? |
Energy per unit area per unit time (J/m^2*yr) or biomass aded per unit area per unit time (g/m^2*yr) |
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In simple terms, what is NPP? |
the amount of new biomass added per time unit |
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Does NPP vary greatly among ecosystems? |
Yes |
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What is Net ecosystem production? |
The total biomass accumulation during a given period |
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How do you get net ecosystem production? |
GPP-total respiration of all organisms (producers and consumers) in an ecosystem |
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How do you measure NEP? |
comparing net flux of CO2 and O2 in an ecosystem |
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What is secondary production? |
amount of chemical energy in food converted to new biomass during a given period of time |
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What is production efficiency? |
The fraction of energy stored in food that is not used for respiration |
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What is the equation of production efficiency? |
(Net secondary production x 100%)/(Assimilation of primary production) |
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Who has the higher production efficiency? Ectotherms or endotherms? |
Ectotherms have higher production efficiency |
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Difference between ectotherm and endotherm? |
Ectotherms (Cold-blooded Animals) Endotherms (Warm-blooded Animals) |
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Which type of ecosystem, aquatic or land transfer energy more efficiently? and why? |
Aquatic 1. "cold-blooded" (LOW METABOLISM) consumers. 2. More rapid turnover in primary producers |
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Why is the biomass pyramid inverted in aquatic ecosystems? |
High primary production, low standing producer biomass |
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What type of ecosystem has the highest global net primary production? |
The ocean |
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T/F Net primary production commonly reaches a peak in young forests after which it declines substantially |
True |
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What are the 3 hypotheses for the fact that Net primary production commonly reaches a peak in young forests after which it declines substantially? And which ones are supported by evidence? |
Not supported by evidence: As trees grow larger with age, they acquire more tissues that respire relative to the photosynthetic tissues in their leaves. Supported by evidence: As forests grow, nitrogen becomes a limiting nutrient. Woody litter accumulates on the soil surface as the forest ages. Woody litter decomposes to leaf litter so it acts as a nitrogen trap. Supported by evidence: As trees grow larger, water transport to the leaves becomes limited due to the increased resistance and this decreases photosynthetic rate. |
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What is the logic behind Charles Darwin's hypothesis that community diversity enhances ecosystem productivity? |
Different species have different resource needs such that the niches of several species would be complimentary. Resource use is more complete with high diversity. |
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What experiment shows that as community diversity increases, productivity decreases? And how so? |
The park grass experiment in 1856 at Rothamsted in England. In plots fertilized with nitrogen productivity increased but species richness declined over time |
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What hypothesis links both observations relating to plant diversity and productivity? |
In plant communities with limiting low nutrients or harsh conditions, we expect a positive relationship between species richness and productivity, but as it becomes really high, competition will lead the dominant species excluding others and reducing species richness. |
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What is facilitation? |
When species have positive effects on the survival and reproduction of other species without the intimate contact of a symbiosis. (The other one benefits or is not affected) |
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What is the competitive exclusion principle? |
2 species competing for the same limiting resource cannot coexist in the same place |
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What is a species ecological niche (ecological role)? |
The sum of a species use of biotic and abiotic resources |
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What is resource partitioning? |
The differentiation of ecological niches, enabling similar species to coexist in a community |
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T/F Coexisting Anolis lizards are known to differ along at least one axis of their niche. |
True |
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What is a fundamental niche? |
Full range of environmental conditions under which it can potentially exist |
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What is temporal partitioning of niches? (also called Conditional differentiation) |
For example: One is nocturnal while the other is diurnal, or one is in dry season and one is in wet |
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what animal is an example of switching to being diurnal from being nocturnal? |
The golden spiny mouse changes when the Common spiny mouse is there |
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Why is the Japanese white eye a threat to native bird populations? |
Because of its broad niche overlap with many species |
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what is the smallest anatomical similarity that will allow two or more species to coexist? |
Ratio of 1.2-1.5 (Character of larger species divided by character of smaller species) |
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Rodent communities in American deserts are comprised of species differing according to body size ratios of at least what? |
1.4 |
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What is character displacement? |
The tendency for characteristics to be more divergent in sympathetic populations of 2 species than in allopatric populations (with a legitimate barrier) of the same two species |
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Is character displacement an evolutionary response? |
Yes |
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How do you test competition? |
Experimental removal of at least one species and observation of population change |
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What is a tropic structure? |
The feeding relationships between organisms in a community |
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What is a food chain? |
Links tropic levels from producers to top carnivores and can have a key role in population dynamics |
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What is a food web? |
Branching food chain with complex trophic interactions |
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Can a species play a role at more than one trophic level? |
yes |
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What is a feeding guild? |
Any group of species that exploit the same food resource through similar methods (ex. grazers, avian predators of rodents, blood sucking insects) |
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What is a functional response? |
The change in the rate at which a predator consumes a prey type including changes in the prey type individual predators consume, and the growth and consumption rates of individual predators. (ex. feeding response, developmental response) |
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What is a numerical response? |
The change in population size or density of a predator including changes in movement of predators (where they aggregate) and reproduction of predators. |
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Changes in what can lead to predator responses? |
Quality, encounter rate and handling time of prey can lead to changes in predator responses, |
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There are 3 general functional responses that are recognized based on whether consumption rate changes and whether consumption rate plateaus at the same max level. Type 1 is like what, and type 2&3 are like what? |
Type 1 is constant consumption with no satiationand type 2&3 have satiation at high prey densities. |
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What are generalists? |
Species consuming many species |
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What are specialists |
Species consuming one or two species |
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Generalists or specialists stabilize prey populations and which one destabilizes prey populations? |
Generalists stabilize prey populations, while specialists destabilize prey populations. |
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What is foraging mode? |
The method is uses to search for prey |
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What are the characteristics of a species that sit-and-wait (ambush)? |
eat infrequently, cover little ground, rely on rapid strikes |
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What are the characteristics of a species that are active foragers? |
Cover large areas searching for prey, consume smaller prey items more frequently |
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What is apparent competition? |
2 species that do not share any resources but whose numbers change in relation to one another because of an indirect effect of a third species, typically a predator |
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Ecological communities are sometimes thought of as highly integrated "super organisms" why? And this view is most developed by who? |
They have predictable origins and development and a set of necessary members that interact in a way that maintains the community Developed by Frederic Clements in early 1990's |
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What is the individualistic concept if ecological communities? |
The only individual physiological requirements and dispersal ability of organisms determine which will be present in a "community" |
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What is succession? |
The sequence of community and ecosystem changes after a disturbance |
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What is the climax community? |
After there are predictable stages which are brought about by interactions of species with their environment and leading to a single end point in any given area |
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What is primary succession? |
When no soil exists before succession |
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What is secondary succession? |
When soil exists before succession |
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Succession where follows a predictable pattern of change in vegetation and soil characteristics? |
In Glacier Bay, Alaska |
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What are the stages in order? |
1. Pioneer (fire weed dormant) 2. Dryas 3. Spruce 4. Alder |
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Succession is the result of what? |
changes induced by the vegetation itself |
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On glacial moraines, vegetation does what to soil pH and does what to soil nitrogen content? |
Lowers soil pH and increases soil nitrogen content |
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T/F Under an inhibition model, succession is considered more individualistic and less predictable |
True |
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What does the tolerance model say? |
Any species can start at the succession, but some species are better competitors and come to predominate in later communities. Species are successively replaced by other species that are more tolerant of limiting resources. |
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What is the difference in population size in r-k selected species? |
r- variable, below carrying capacity k- constant, close to carrying capacity |
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What is the difference in intra/interspecific competition in r-k selected species? |
r-variable, weak k - strong |
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The yellowstone forest is an example of a community maintained by what? |
periodic fires |
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T/F The natural fire regime maintains a conifer forest in the southeast where there would otherwise be a temperate broad leaf community |
True |
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What do non equilibrium models focus on? |
finer spatial scales and recognize frequent change in species abundances |
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What are 2 categories of non equilibrium models? |
Bottom up- unidirectional influence from lower trophic levels to higher trophic levels. (Presence/absence of mineral nutrients determines community structure, including abundance of primary producers) Top down- (Trophic cascade) - control of dynamics at each trophic level comes from the trophic level above. (predators control herbivores, which control primary producers) |
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What is biomanipulation? |
Planned intervention at a particular trophic level to restore communities after disturbance |
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What is the intermediate disturbance hypothesis? |
Moderate levels of disturbance can foster greater diversity than high or low levels of disturbance |
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High level disturbance exclude what kind of species? |
Slow growing |
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Low levels of disturbance allow what? |
Dominant species to exclude less competitive species
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What are the 2 key factors in why species richness is greater in the tropics and declines along an equatorial-polar gradient? |
evolutionary history - temerate and polar communities have started over repeatedly following glaciations. The greater age of tropical environments may also account. climate - growing season is longer so biological time runs faster |
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What are 2 main climatic factors correlated with biodiversity? |
Solar energy and water availability |
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how do you measure solar energy and water availability together? |
Evapotranspiration - the rate of the evaporation of water from the soil plus the transpiration of water from plants is measured. |
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What is a species-area curve? |
It quantifies the idea that, all other factors being equal, a larger geographic area has more species |
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What is the equation for the species-area curve? |
S=cA^z S=number of species c- a constat; species per unit area A- Area of land mass z - a constant; the slope of the S vs A line |
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Slope of the species area curve tends to be about what for a variety of islands? |
0.3 |
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Relationships on continents tend to have a lower slope, why? |
IDK |
