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12 Cards in this Set
- Front
- Back
Survivorship curves
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Type I- humans, most individuals survive to middle age and after that mortality is hight
Type II- rodents and invertebrates, length of survivorship is random and the likelihood of death is the same at any age. Type III- oysters, describes species in which most individuals die young |
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Population
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A group of individuals of the same species living in the same area.
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Community
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A group of populations living in the same area.
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Ecosystem
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Describes the interrelationships between the organisms in a community and their physical environment.
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Biosphere
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Composed of all the regions of the earth that contain living things.
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Habitat
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The type of place where an organism usually lives.
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Niche
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Describes all biotic and abiotic resources in an environment used by an organism. When an organism occupies a niche, it means that certain resources are consumed or certain qualities of the environment are changed in some way by the presence of the organism.
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Biotic potential
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The maximum growth rate of a population under ideal conditions with unlimited resources and without any growth restrictions. Factors that contribute: age of reproductive maturity, clutch size, frequency of reproduction, reproductive lifetime, surivorship
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Carrying capacity
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The maximum number of individuals of a population that can be sustained by a particular habitat.
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Limiting factors
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Those elements that prevent a population from attaining its biotic potential. Include:
Density dependent- effects become more intense as the density of the population increases (parasites, predation) Density independent- occur independently of density and include natural disasters and extreme climates. |
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Population growth equation
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r= birth-deaths/N
r= reproductive rate N=population size |
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Two growth patterns
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1. Exponential- occurs whenever the reproductive rate is greater than zero. On a graph where population size is plotted against time, a plot of exponential growth rises quickly, forming a J-shaped curve.
2. Logistic growth- occurs when limiting factors restrict the size of the population to the carrying capacity of the habitat. Results in an S shaped curve. |