Quantification of microevolutionary patterns: Multivariate rates and patterns of evolution in the Neogene diatom lineage Nitzschia jouseae Burckle.
Item
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Title
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Quantification of microevolutionary patterns: Multivariate rates and patterns of evolution in the Neogene diatom lineage Nitzschia jouseae Burckle.
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Identifier
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AAI8820860
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identifier
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8820860
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Creator
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Fenster, Eugene Joel.
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Contributor
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Adviser: Max Hecht
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Date
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1988
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, General
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Abstract
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A study of the rates and patterns of morphological change in the Neogene diatom Nitzchia jouseae over its known duration and geographic range was conducted. This study developed a standardized multivariate method for the measurement of morphological rates of change. This method can be applied to taxa differing in morphology. This method consists of using the first canonical variate means to create a measure of rate in terms of standard deviation units. Stasis is defined as that period of time during which the slope of the canonical means is near zero. It is suggested that the history of a lineage be divided into segments and that the rate be calculated as the slope of the first canonical variate means of each segment. Fluctuations in mean morphology about an adaptive peak may be attributable to factors such as minor environmental perturbations and sampling error. This provides a theoretical basis for the division of the history of a lineage. Each segment represents a major trend in the history of the lineage.;The pattern of morphological change exhibited by N. jouseae is divided into two phases: the first stage is characterized by directional change in morphology, the second phase, which extends through the last appearance of the species is characterized by little morphological change. At any given temporal horizon there are few differences, if any, in morphology between samples taken from different water masses. The pattern of morphological change with both of these stages conforms to the Raup and Crick model of deviations in morphology within selective bounds.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
