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Full-Text Articles in Ecology and Evolutionary Biology

A Paleocene Flora From The Fort Union Formation Near Baggs, Carbon County, Wyoming, John L. Roth Jul 1975

A Paleocene Flora From The Fort Union Formation Near Baggs, Carbon County, Wyoming, John L. Roth

Theses and Dissertations

A well-preserved Paleocene flora of 39 species from the Fort Union Formation near Baggs, Carbon County, Wyoming has been studied. This is the first study of the plant megafossils in this area. The most abundant species collected are: Carya antiquorum Platanus nobilis, Cercidiphyllum arcticum and Platanus raynoldsi. Together they represent 74% of the flora. The flora has been dated as Upper Middle Torrejonian. This report is also the first paleoecological study of any North American Paleocene flora. Two methods were used to determine the paleoclimatic conditions of the flora. The first was an analysis of leaf margin characteristics, comparing them …


Diatom Phytoplankton And Periphyton Studies Of The Headwaters Of Henrys Fork Of The Snake River, Island Park, Idaho, Richard L. Clark Apr 1975

Diatom Phytoplankton And Periphyton Studies Of The Headwaters Of Henrys Fork Of The Snake River, Island Park, Idaho, Richard L. Clark

Theses and Dissertations

An ecological baseline study of the diatom flora was conducted on the headwaters of Henrys Fork of the Snake River, Idaho. The diatom flora of this spring fed drainage basin consisted of both phytoplankton and periphyton. Thirty-nine genera, two hundred forty-four species, eighty-two additional varieties, and seven additional forms were identified from these waters. Species of Melosira, Stephanodiscus, Fragilaria, Synedra, and Asterionella were found in the plankton of Henrys Lake and Island Park Reservoir. Diatoma, Fragilaria, Synedra, Eunotia, Achnanthes, Navicula, Pinnularia, Gomphonema, Cymbella, Nitzschia, and Surirella were the important genera present in the periphyton.


A Comparative Study Of Some Population Characteristics Of Calyptraea Fastigiata Gould, Crepidula Lingulata Gould, And Crepidula Nummaria Gould (Gastropoda, Prosobranchia), Roger Harold Goodwill Apr 1975

A Comparative Study Of Some Population Characteristics Of Calyptraea Fastigiata Gould, Crepidula Lingulata Gould, And Crepidula Nummaria Gould (Gastropoda, Prosobranchia), Roger Harold Goodwill

Theses and Dissertations

A comparative study of the field populations of Crepidula lingulata, Crepidula nurnmaria, and Calyptraea fastigiata indicated all three preferred a rocky substrate but favored different size rocks. Their positions on the rocks varied but the greatest numbers were found attached to the undersides. Crepidula lingulata and C. nummaria preferred larger rocks and were found in intraspecific associations more often than C. fastigiata which preferred smaller rocks. These associations occurred with a 1:1 sex ratio; however, the overall population did not. Crepidula lingulata had a high female count and C. fastigiata a high male count. Males, of all three species, were …