Life Sciences Commons^™

Modern Invertebrate Footprints Compared With Fossil Footprints From The Coconino Sandstone (Permian), Marilyn A. Emtage

Loma Linda University Electronic Theses, Dissertations & Projects

Laboratory studies of trackways of the crayfish, Cambarus clarkii were conducted, and the footprints compared with fossil invertebrate footprints (Paleohelcura sp.) of the Permian Coconino sandstone of Northern Arizona, and similar footprints of other sandstone. Fine grained sand (similar to that composing the Coconino sandstone) was placed in a plexiglass tank to form slopes of various angles. The crayfish walked up and down slopes of 10°± 3°, 20°± 2°, 25° and on level sand, and their trackways were photographed. Trackways were produced on wet sand and underwater sand, but the animals would not walk on dry sand. Clear individual impressions …

The Effect Of Carbon Dioxide Concentration On Calcification In The Red Coralline Alga Bossiella Orbigniana, A. Dwight Smith

Loma Linda University Electronic Theses, Dissertations & Projects

The relationship between various experimental concentrations of CO2 and calcification was studied by measuring Ca-45 incorporation into the crystalline matrix. Air containing CO2 at partial pressures (Pc02) of 0.04% to 5.5% was bubbled through synthetic sea water in incubation vessels. The resultant pH values ranged from 8.7 to 6.5. The relative concentrations ofCO2, HCO3 , and CO2— 3 were calculated from the measured ' pH—PCO2 combinations. Calcification was correlated positively with HCO expressed as percent of total carbon. Maximum calcification of about one—third above normal occurred between 0.1% and 1.0% P CCOO22 At 0.26% P calcification increased as increments of …

An Analysis Of Species Recognition In Sympatric, Allopatric And Reciprocally Cross-Fostered Peromyscus Californicus And Peromyscus Eremicus (Rodentia, Cricetidae), Ronald L. Carter

Loma Linda University Electronic Theses, Dissertations & Projects

Experiments were performed to compare homospecific and heterospecific mate selection in two closely related species, Peromyscus californicus and Peromyscus eremicus. Comparisons were made between allopatric and sympatric populations and between males and females for mate selection performance. Both species made significant choice for the homospecific chambers. Significant homospecific choice was made by mice from sympatric populations, whereas allopatric populations did not demonstrate significant choice. No significant difference in choice performance was demonstrated between males and females even when the estrus stages of the females were controlled.

A comparison of different testing lengths and temporal regimes of data collection was performed …

The Distribution Of Orcuttia Californica (Poaceae) In The Vernal Pools Of The Santa Rosa Plateau, Riverside County, California, Cluney M. Stagg

Loma Linda University Electronic Theses, Dissertations & Projects

Ecological studies were conducted on the rare annual grass Orcuttia californica (Vasey), an endemic to California, from April to September, 1976 in 11 vernal pools located on the Santa Rosa Plateau in Riverside County. To help determine why Orcutt grass occurs in only 6 of the 11 pools and more specifically why it only occurs in patches within a given pool, biweekly measurements of frequency, density and phenology were taken within each of a total of 28 circular plots (r = 10 meters) in 5 pools. This data was related to concurrent biweekly measurements of soil moisture, soil texture and …