Ecology Exam 4

competition among members of the same species

competition among individuals of different species

• Any substance or factor that is both consumed by an organism and supports increased population growth rates as its availability increases​

• Consumed, availability decreases​

• Used for maintenance and growth​

• Reduced availability reduces population growth​

resources that are constantly regenerated (seeds, sunlight)

resources that are not regenerated(space)

law stating ​that a population increases until the supply ​of the most limiting resource prevents it ​from increasing further.​

two species cannot coexist indefinitely when they are both limited by the same resource.​

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When two species are limited by the same resource, one species is often a better competitor survives better when resources are scarce.​ (Grocery store ham example)

• coexistence​

• Species 1 Wins (Drives Species 2 to local extinction)​

• Species 2 Wins (Drives Species 1 to local extinction)​

• Winning species depends on starting conditions​

A competitive relationship between two species in which each has a competitive advantage with respect to different limiting factors in the environment​

competition in which individuals consume and drive down the abundance of a resource to a point that other individuals cannot persist.​ (the sister in the milk example)

when competitors do not immediately consume resources but defend them; considered direct competition.​ (the brother in the milk example)

when two species have a negative effect on each other through an enemy—including a predator, parasite, or herbiviore.​

a type of interference competition that occurs when organisms use chemicals to harm their competitors.​ (effective strategy for invasive plants)

r1N1(1-N1+aN2/K1) = N1

r2N2(1-N2+BN2/K2)= N2

α = competition coefficient for species 1, which converts individuals of species 2 into the equivalent number of individuals of species 1.​

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β = competition coefficient for species 2, which converts individuals of species 1 into the equivalent number of individuals of species 2.​

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• # of individuals using resources of species 1 ​= N1 + α • N2​

• # of individuals using resources of species 2 ​= N2 + β • N1​

An assemblage of species that occur together in the same place​

1. Superorganism – Holistic concept​

- (Frederick) Clements​

2. Individualistic concept​

-(Henry) Gleason​

Communities are a distinct ecological unit or organization having recognizable boundaries and whose structure and functioning are regulated by interaction among its component species​

requires that communities be discrete entities and distinguishable from one another

a loose assemblage of species that can tolerate the conditions of a particular habitat​

Does not require boundaries

distributions of species sets closely coincide and are separated from other sets of species

species are independently distributed along environmental conditions​

the number of species in a community.​

the proportion of individuals in a  community represented by each species.​

a normal, or bell-shaped, distribution that uses a logarithmic scale on the x-axis.​

a species that substantially affects the structure of communities, although species might not be particularly numerous.​

the hypothesis that more species are present in a community that experiences occasional disturbances than in a community with either frequent or rare disturbances.​

a linear representation of how different species in a community feed on each other.​

a complex and realistic representation of how species feed on each other in a community.​

a level in a food chain or food web of an ecosystem.​

Species that eats producer

a species that eats primary consumers.​

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a species that eats secondary consumers.​

a species that feeds at several trophic levels.​

within a given trophic level, a group of species that feeds on similar items; members of the group are not necessarily related.​

Informality of construction​

Lumping species into guilds or categories​

Ignore changing roles (catfish: detritivore/predator)​

All links equal, although may vary in strength​

Most are fairly short (average = 4 links in previous)​

Most are open (receive significant input from and export to adjoining systems)​

: when the abundances of trophic groups are determined by the amount of energy available from producers.​

when the abundances of trophic groups are determined by the existence of predators at the top of the food web.​

the ability of a community to maintain a particular structure.​

the amount a community changes when acted upon by a disturbance (e.g., addition or removal of a species).​

the time it takes after a disturbance for a community to return to its original state.​ (diversity improves this)

the process by which the species composition of a community changes over time.​

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each step of community change during succession

the earliest species to arrive at a site; typically are able to disperse long distances and arrive quickly at disturbed sites.​

the final seral stage in the process of succession; generally composed of organisms that dominate in a given biome.​

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a sequence of communities that exist over time at a given location.​

the development of communities in habitats that are initially devoid of plants and organic soil, such as such dunes, lava flows, and bare rock.​

the development of communities in disturbed habitats that contain no plants but still contain organic soil (e.g., plowed fields, forests uprooted by a hurricane).​

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1. After a lake or pond is created, the edge of the water body is initially colonized by plants.​

2. The plants expand laterally across open water and begin accumulating dead plant matter (i.e., peat).​

3. Plants continue to expand and the peat layer becomes thicker.​

4. Lateral expansion of plants eventually covers the lake surface and peat sediments fill in the basin.​

1. An open lake or pond experiences a drought of one or more decades and the water level falls.​

2. Plants colonize the newly exposed lake sediments.​

3. As the drought ends, the lake fills and living plants detach from lake sediments and float on the lake’s surface.​

4. Peat sediments eventually fill the basin.​

a mechanism in which one species increases the probability that a second species can become established.​

a mechanism in which one species decreases the probability that a second species will become established (e.g., by competition, predation, or parasitism).​

when the arrival of species at a site affects the colonization of other species; often occurs through inhibition.​

when the arrival of species at a site affects the colonization of other species; often occurs through inhibition.​

A climax community that develops in an ephemeral habitat (ex. seasonal ponds)

a climax community that is not persistent; occurs when a site is frequently disturbed so a climax community cannot persist.​

A repeating sequence of stages of succession, none of which by itself is stable, but together represent a persistent pattern​

a successional stage that persists as the final seral stage due to periodic fires.​

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when a successional stage persists as the final seral stage due to intense grazing.​

the assemblage of organisms together with their physical and chemical environments​

introduced idea of food web and energy transfer within the web​

Introduced the term “ecosystem” as the fundamental unit of ecological organization

the study of natural systems from the standpoint of energy flow and cycling of matter​

• Conservation of Energy​

• Entropy increases due to inefficiency​

• Treats ecosystems (and the Earth) as giant thermodynamic machines​

the rate at which solar or chemical energy is captured and converted into chemical bonds by photosynthesis or chemosynthesis.​

the biomass of producers present in a given area of an ecosystem at a particular moment in time.​

the rate at which energy is captured and assimilated by producers in an area.​

the rate of energy that is assimilated by producers and converted into producer biomass in an area; includes all energy that is not respired:

a technique that allows measurement of conditions on Earth from a distant location, typically using satellites or airplanes that take photographs of large areas of the globe.​

• 5-20% of energy passes to next trophic level (~10%)​

• Why?

- Assimilated energy​= ingested – egested energy​

-Production​= assimilated energy – respiration - excretion​

the percentage of net production from one trophic level compared to the next lower trophic level.​

• Chemical elements reused constantly​

-Cycle between biologically usable and un-usable states (organic and inorganic)​

• Energy is gained or lost during transformations​

-Oxidation—gives up electrons (loses energy)​

-Reduction—accepts electrons (gains energy)​

• Assimilatory Processes—inorganic→organic​

-Requires energy (Photosynthesis)​

• Dissimilatory Processes—organic→inorganic​

-Releases energy (Respiration)​

the process of solar radiation striking Earth, being converted to infrared radiation, and being absorbed and​ re-emitted by atmospheric gases.​

the latitude receiving the most direct rays of the Sun.​

the fraction of solar energy reflected by an object.​

the circulation of air between the surface of Earth and the atmosphere; caused by properties of air.​

the limit of the amount of water vapor that air can contain.​

the cooling effect of reduced pressure on air as it rises higher in the atmosphere and expands.​

the heating effect of increased pressure on air as it sinks toward the surface of Earth and decreases in volume.​

when water vapor is converted back to liquid, water releases energy in the form of heat and warms air.​

the two circulation cells of air between the equator and 30N and 30S latitudes.​

the area where the two Hadley cells converge and cause large amounts of precipitation.​

atmospheric convection currents between 60 and 90 latitudes that are similar to Hadley cells. ​

the deflection of an object’s path due to the rotation of the Earth.​ (wind isnisn’tt air moving against earth, it is earth moving against air)

a large-scale water circulation pattern between continents.​

and upward movement of ocean water

a region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean causing precipitation on the windward side.​

characterized by warm temperatures and high precipitation, occurring in regions near the equator.​

characterized by low precipitation and a wide range of temperatures; found at approximately 30N and 30S latitudes.​

characterized by warm, dry summers and cold, wet winters.​

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exists in the interior of continents and is characterized by warm summers, cold winters, and moderate amounts of precipitation.​

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