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Wednesday, May 10, 2017

Biological Principles 2 -- 58.LS



A community that is in equilibrium can be characterized by which of the following?
·         It has stable species-richness
·         It has stable species diversity
The individualistic model describes a community as an assemblage of species coexisting due to similarities in physiological tolerances and requirements.
Match how competition affects succession according to the tolerance model.
·         Competition-inteolerant species: successful early in succession
·         Competition-tolerant species: successful late in succession
The relationship between the available area and the number of species present is called the species-area effect.
Which of the following are factors of the facilitation process that assist in the establishment of a climax community?
·         Facilitation promotes the invasion of new colonists
·         Facilitation results in the most dominant species colonizing the community
Which of the following are factors that a community ecologist would address when studying a community?
·         Factors that stabilize species number
·         Factors that stabilize species abundance
Primary succession occurs after a glacier retreats.
Disturbance may increase species richness because of which of the following?
·         it creates micro-habitats that are different than the overall habitat of the area
·         it causes a progression of species who are competing for resources in the area it re-establishes after disturbance
·         it provides niches for species that otherwise would not survive in an area
Identify the steps of facilitated succession in order following a glacial retreat.
1.       Cyanobacteria, mosses, and lichens increase soil nitrogen content
2.       Seedlings of shrubs begin to colonize
3.       Soil depth and litter fall increase, and alder trees invade
4.       As soil nitrogen and litter fall increase, spruce trees begin to invade
5.       Soil becomes acidic and hemlock seedlings appear
A community is an assemblage of many species living in the same place at the same time.
The number of species in a community is referred to as its species richness
The intermediate-disturbance hypothesis predicts that areas with moderate habitat disturbance will have higher levels of species richness.
The productivity hypothesis predicts that species richness can be predicted by the total amount of plant material produced over time.
Which of the following describe the principle of species individuality?
·         Competition does not create distinct vegetational zones
·         Most communities intergrade
·         Species are distributed based on physiological needs
A mechanism of succession in which earlier species make the area more suitable for subsequent species is called facilitation.
The four main hypothesis for explaining differences between species richness in different geographical areas are the area hypothesis, the time hypothesis, the productivity hypothesis, and the intermediate-disturbance hypothesis.
A series of changes in ecological community after a forest fire has destroyed the vegetation is an example of secondary succession.
Primary succession refers to a series of changes in a biotic community that occurs after a bare expanse of ground becomes newly exposed.
The gradual and continuous change in species composition and community structure over time is called succession.
A series of community changes resulting from a tsunami is secondary succession, whereas a series of changes to the community resulting from the formation of a new coastal sand dune is primary succession.
Species richness generally increase with decreasing latitude, from polar regions to tropical regions.
According to the organismic mode, communities are predictable, integrated associations species separated by sharp boundaries.
Primary succession begins with a bare expanse of newly exposed rock, whereas secondary succession begins with an existing community that has been dramatically altered.
Species-rich communities are generally considered more stable than species poor communities.
The relationship between the available are and the number of species present is called the species-area effect.
The intermediate-disturbance hypothesis predicts that areas that has some continuous habitat disturbance will have the highest degree of species richness.
Community ecology is the study of the interactions among individuals within coexisting populations found in a specific area.
The productivity hypothesis predicts that species richness can be predicted by the total amount of plant material produced over time.
According to the diversity-stability hypothesis, high diversity communities are more resistant to disturbance than low diversity communities.

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