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45 Cards in this Set
- Front
- Back
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What is Community Ecology?
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The study of interacting species within an area
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What is a Niche?
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The sum total resources used by a species. The ecological job description.
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What is a fundamental Niche?
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The total possible use of the environment by a species without competitors
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What is a realized Niche?
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The actual observed use of the environment by a species with competitors
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What is the Competitive Exclusion Principle?
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2 species cannot occupy the exact same niche
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Competition
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Both species decrease in fitness. Species with overlapping niches compete with eachother
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What are the 2 types of Competition?
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1. Symmetric-Each species experiences the same decrease in fitness.
2. Asymmetric-One species has a greater fitness decrease compared to the other. |
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Why aren't there just a few superior competitors as a result of Asymmetric Competition?
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Most Niches don't completely overlap and natural selection favors individuals that do not overlap/compete for niches
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What is Interference Competition?
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Species interfere with another's use of a resource
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What are examples of Interference Competition?
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Overgrowth, territorial, encounters, chemical
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What is Exploitation Competition?
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Species both utilize a resource, but the more efficient consumer wins.
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Commensalism
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One species gains in fitness, the other in unaffected. Ex: Whales and sucker fish
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Consumption
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One species increases in fitness and one loses in fitness. Ex: a cow eating grass. A parasite and a host
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Amensalism
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One species' fitness is not affected and the other species' fitness is decreased. Ex: a person is walking and steps on a bug.
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Mutualism
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Both species gain in fitness. Ex: Ants and Acacia trees, bees and flowers
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What is a Constitutive Defense?
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A defense that is always in use, constantly turned on. Ex: camouflage, schooling, weaponry (porky pine)
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What is an Inducible Defense?
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A defense that is only produced in response to predators. It reduces the cost of fitness. Ex: Cottonwood trees increase their chemicals after they are cut down.
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What is Mullerian Mimicry?
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Species with similar defenses that resemble each other. Ex: Hornets and Bees look alike and both have stingers
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What is Batesian Mimicry?
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Species without a defense try to resemble a species that has a defense. Ex: Colorful frogs
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Top Down Control of Consumption
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The amount of predators controls the prey population
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Bottom Up Control of Consumption
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The amount of Prey regulates the predator populations
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Indirect Community Interactions
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Two species that do not directly interact, but exert influences on each other. Generally, there is a middle species involved. It works as a trophic cascade.
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What is a keystone species?
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A species with effects on communities that are disproportionate to their biomass. Small part of the ecosystem but big impact
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What is species richness?
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The total number of species
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What is species diversity?
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the weighted measure that includes both species and abundance
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What causes species diversity?
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Many terrestrial ecosystems show patterns of decreasing diversity with latitude. Farther away from the equator = less diversity
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What is the Productivity Hypothesis?
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High productivity supports more species. Supports bottom up control. Supported by natural patterns, but contradicted by experimental studies
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What is the Area Hypothesis?
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Larger areas support more species. The tropics is the only area with N/S hemisphere regions. Supported by studies
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What is the Intermediate Disturbance Hypothesis?
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In a community, if there are frequent disturbances then there will be few species. R selected species will dominate.
If there are few disturbances, then there will also be few species. K selected species will dominate. If there are intermediate disturbances, then there will be many species. |
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What is the role of Ecological Diversity?
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Diverse ecosystems are able to use more of the resource base, this results in higher productivity. Also, it is more likely to bounce back from a disturbance
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What is ecological resistance?
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A measure of how much a disturbance affects a ecosystem
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What is ecological resilience?
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A measure of how quickly a community bounces back from a disturbance
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What is the Net Primary Productivity? NPP
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The amount of plant material available to herbivores and decomposers
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Clements's View of Community Development. Incorrect View
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He saw communities as super organisms, species worked cooperatively
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Gleason's View of Community Development. Correct View
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Communities are a collection of individual species with unique physiological tolerances. Very individualistic.
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What is Succession?
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The recovery of a community after a disturbance.
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What is Primary Succession?
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All the species and soil are removed. Ex: glacial flow or lava flow
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What is Secondary Succession?
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Some or all of the species are removed, but the soil is left intact. Ex: fire, flood, strong storms
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Early Successional Communities
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Pioneer species colonize these communities. High dispersal, fast growing, short lived
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Late Successional Communities
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Long lived, slow growing, superior competitors colonize these communities
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Climax Community
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A stable, persistent community.
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Species Interactions during Succession: Facilitation
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One species makes conditions more tolerable for another
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Species Interactions during Succession: Inhibition
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One species prevents or makes it difficult for the establishment of another species
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Species Interactions during Succession: Tolerance
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Existing species do not influence the arrival of a new species
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Today's View of Succession depends on..?
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1. Traits of the species involved
2. Species interactions 3. Environmental circumstances |
