Life Sciences Commons^™

A New Hypothesis Conerning The Sequence And Nature Of Meiotic Events In The Female Of Drosophila Melanogaster, Rhonda F. Grell

Doctoral Dissertations

Three of the basic phenomena comprising the meiotic process are synapsis, crossingover, and disjunction. It is generally conceded that some form of pairing must precede crossingover; that the crossingover process occurs prior to disjunction; and that disjunction implies a previous association of elements. Construction of a model describing the causal relations among the three events might be expected to be fairly simple, since the possibilities are limited. Yet, no model has been proposed that is consistent with all the genetic data.

Some Environmental Features Of Hallett Station, Antarctica, With Special Reference To Soil Arthropods, Madison E. Pryor

Doctoral Dissertations

Introduction: Since Cook's voyage of 1772-1775, numerous expeditions, nationally and independently supported, have explored coastal and inland areas of Antarctica. The primary purpose of most early scientific expeditions was directed toward a study of the physical nature of the continent. In most instances, biologists were not included as expedition personnel and a large portion of the information concerning the flora and fauna of the continent has been contributed by investigators trained in a variety of scientific disciplines. A very few systematic investigations of land flora and soil fauna have been made. In spite of the obvious inadequacy of such investigations, …

Studies On The Morphology And Growh Rate Of The Cestode Hymenolepis Microstoma After Gamma Irradiation Of The Cysticercoids And Eggs, Huldrich H. Kuhlman

Doctoral Dissertations

From the literature on effects of radiation on mammals, insects, and other organisms, it appears that radiation produces abnormalities chiefly by destroying or inhibiting growing cells and tissues. The effects on length of the worms may be due to reduction in cell population responsible for growth. The presence of certain morphological abnormalities which have been observed, particularly those which have been characterized by the absence of one or more reproductive organs, might also be attributed to a change in the growth or embryological apparatus and that radiation only serves to increase the frequency of these disturbances.

For further similar studies …

Meiosis, Mitosis, And The Induction Of Chromosomal Abnormalities In Hymenolepis Diminuta By Gamma Rays, Raymond Louis Kisner

Doctoral Dissertations

Summary

A growth rate study for H. diminuta in ten worm infestations was attempted. The desired number of worms was not recovered from enough rats to determine a reliable growth curve. It was discovered that worm length varied within rats and between rats of comparable sex, age, weight, worm burden, and genetic background.

The Strawberry Leaf Roller Complex In Tennessee, Stelmon Emerson Bennett

Doctoral Dissertations

This study was undertaken in order to learn the basic biology of the strawberry leaf roller Ancylis comptana fragariae in Tennessee. Shortly after the initiation of the study, it was found that not one, but several forms of leaf roller larvae were involved in the damage being done to strawberries. The study was therefore broadened to include the entire complex of leaf roller species and subspecies which inflict damage to strawberries and sometimes to other host plants in Tennessee. Three of the eleven forms making up the complex were selected as being most important because of their abundance and the …