Spelling suggestions: "subject:"biology, zoology"" "subject:"biology, noology""
291 |
The secondary sexual characters of Plethodontid salamanders with especial reference to Eurycea quadridigitata (Holbrook)January 1974 (has links)
acase@tulane.edu
|
292 |
Seasonal variations in habitat availability, habitat selection, and movement patterns of Myocastor coypus on a subtropical freshwater floating marshJanuary 2006 (has links)
I employed a combination of vegetative sampling, GIS mapping, and radiotelemetry to examine habitat availability, habitat selection, and movement patterns of the invasive nutria on a freshwater floating marsh at Jean Lafitte National Historical Park and Preserve (JLNHPP) in southeastern Louisiana. I found that the floating marsh is both spatially and temporally dynamic at the plant species level. Nutria at this study site had larger home ranges than reported for most other nutria studies. This finding could be attributed to a low to moderate population density, patchy resource distribution, and/or improved telemetry techniques. I evaluated habitat selection at three different scales, or orders of selection; the home range, the location point habitat type, and the individual plant species composition at location points. Nutria did not select habitat at the home range or habitat type level; i.e. they did not select based upon broad-scale habitat characteristics or by dominant plant species. Across all seasons, nutria selected habitats that were significantly different from those available to them at the plant species level. Male and female nutria did not differ significantly in their overall patterns of habitat use and movement. These findings suggest that nutria occupy a spatially and temporally dynamic habitat and that their utilization of this habitat depends heavily upon the individual plant species present at a specific locale / acase@tulane.edu Read more
|
293 |
An ultrastructural study of skin allograft rejection in the leopard frog, Rana pipiensJanuary 1974 (has links)
acase@tulane.edu
|
294 |
The anthropoid hand: a comparative study of prehensionJanuary 1973 (has links)
acase@tulane.edu
|
295 |
Circadian locomotor activity rhythms in the crayfish and their entrainment to light cyclesJanuary 1974 (has links)
acase@tulane.edu
|
296 |
Distribution and abundance of frogs in a central Amazonian forestUnknown Date (has links)
This study is the first comprehensive survey of a frog assemblage in the central Amazon. Forty-three species of frog were found in a 2,000 hectare tract of primary forest near Manaus, Brazil. Breeding habitat affiliation, breeding phenology, spatial distribution, and relative abundance were determined for most species principally by counting calling males along variable-width strip transects. Frogs were also censused with visual detection methods and in litter plots. However, these techniques were not as powerful as audio transects for assessing species composition, habitat occupancy, and abundances throughout a large area. Anuran species and generic richnesses are similar throughout the Amazon except for Eleutherodactylus which is depauperate in the central and lower Amazon. As many species were abundant in the study area as were rare. The distribution of breeding habitat abundance parallels the distribution of species-abundance and so breeding habitat availability seems the best candidate to explain the relative abundances of species in the study area. / There is pervasive correlation between life history variables, particularly reproductive mode and habitat affiliation, and phylogeny in tropical forest anurans. This association supports a hypothesis that, at a regional scale, the history of an area's colonization and speciation rates of the colonists influenced the distribution of habitat use by frogs in forest assemblages more than selection. / Litter plot sampling was biased in favour of conspicuously behaving litter species. Since the proportion of the litter fauna that is conspicuously behaving is much lower in southeast Asia than the Neotropics, there is no evidence that litter frogs per se are more abundant in the Neotropics. However, abundances of conspicuously behaving species are higher in the Neotropics. Practically all abundant species at Manaus undergo terrestrial development. It appears that terrestrial reproduction releases frog populations from dependence on limited aquatic habitat. Since two prominent Neotropical families of litter frog reproduce terrestrially whereas terrestrial development is not associated with any southeast Asian taxon, the historical colonization of these regions by different lineages explains inter-regional abundance differences most parsimoniously. / Source: Dissertation Abstracts International, Volume: 52-04, Section: B, page: 1904. / Major Professor: Daniel Simberloff. / Thesis (Ph.D.)--The Florida State University, 1991. Read more
|
297 |
Appetitive search behaviors and stereotypies in captive animalsFernandez, Eduardo J. January 2009 (has links)
Thesis (Ph.D.)--Indiana University, Dept. of Psychological Brain Sciences, 2009. / Title from PDF t.p. (viewed on Feb. 10, 2010). Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3770. Adviser: William Timberlake.
|
298 |
Ecology and conservation of the twin-spotted rattlesnake, Crotalus priceiPrival, David Benjamin January 2000 (has links)
Although twin-spotted rattlesnakes (Crotalus pricei ) were first identified more than a century ago, little has been published about the ecology of this species and no information has been available regarding population characteristics. During 1997--99, I captured, measured, and marked 117 C. pricei in the Chiricahua Mountains to address this need for information. Lizards constituted the bulk of C. pricei prey, but their diet also included mammals, birds, and snakes. Mating and parturition were concentrated in August and early September. Movement patterns varied dramatically from year to year, as males moved substantially farther during the 1998 monsoon season (July--September) than in 1997. Crotalus pricei are sometimes collected illegally for the pet trade. About 90 people may have hunted for C. pricei at a well-known site during 1997--98. On average, snakes at this site were 38.1 mm smaller than snakes at other sites, an observation that could be attributed to collecting pressure.
|
299 |
Variation in Tetragnathid spermathecal structures and sperm competition with descriptions of natural historyDanielson-Francois, Anne January 2002 (has links)
The study of variation in arachnid genitalic structures has contributed to the fields of systematics and sexual selection. Simon (1892--1903) in his Histoire Naturelle des Araignees first divided the ecribellate higher spiders into two groups, the Haplogynae and Entelegynae, using reproductive morphology. Spider genitalia have been used as a taxonomic tool for distinguishing between taxa because of their species-specific morphological variation. Variation in spider genitalic morphology has inspired evolutionary biologists to test mechanisms of sexual selection by which the variation could evolve, ranging from Fisherian run-away selection, chase-away selection, and sperm competition. The Tetragnathidae are particularly interesting for a comparison between haplogyne and entelegyne reproductive morphologies. Within this entelegyne family, a reversal to haplogyny has occurred. Fifteen representative members of this family and four outgroup taxa were examined with scanning and transmission electron microscopy in order to describe the fine structure of spermathecae, including the distribution and density of spermathecal gland pores. While the function(s) of the glandular secretion are unknown, the distribution and density of spermathecal gland pores is discussed with regard to possible functions of the glandular secretion. The potential influence of spermathecal gland secretions on mating behavior and sperm competition is considered. Sperm release patterns have been examined in entelegynes, but previously were not available for haplogynes. The relationship between copulation duration and sperm release was determined in Tetragnatha versicolor, the first examination of sperm release patterns in any haplogyne spider. In this species, copulation duration is not proportional to sperm release. To examine the relative influence of spermathecal morphology and numerical sperm competition on paternity, sperm release and paternity was assessed in the entelegyne Nephila clavipes and the haplogyne Tetragnatha versicolor. The data clearly support differential sperm release between males as the cause of previously reported first-male advantage in Nephila clavipes and the mixed paternity found for N. clavipes and Tetragnatha versicolor in this study. The natural history, mating behavior, and sperm release were determined for a previously unstudied tetragnathid species, Glenognatha emertoni . This is the second examination of haplogyne sperm release behavior as well as the first description of an unusual escape behavior. Read more
|
300 |
The integration of digestive, metabolic and osmoregulatory processes in nectar-eating birdsMcWhorter, Todd Jason January 2002 (has links)
Nectarivorous birds are represented by three major radiations: hummingbirds, honeyeaters, and sunbirds. These lineages share a number of convergent features in ecology, morphology, physiology, and behavior, and have served as important models in the study of foraging strategies and energetics. Because their diet is rich in water and sugar but poor in nitrogen and electrolytes, nectarivores provide a striking opportunity for evaluation of physiological constraints. My research emphasizes a novel aspect of the water-energy interaction: water overingestion in nectar-eating birds. The dual purpose of my dissertation research was to investigate the physiological mechanisms that allow nectar-eating birds to cope with exceedingly high ingestion of water and to elucidate the consequences of ingesting and processing large quantities of water for energy intake and for the maintenance of balance of important metabolites such as glucose. In nectar-eating birds, water overabundance in food has the potential effect of constraining energy procurement by overwhelming osmoregulatory processes and limiting digestive function. My research has allowed the development of an integrated quantitative description of gut and kidney function under the broad range of water loads and hydration conditions that birds can experience in the wild. Understanding limits to water processing will provide general insights into how animals are designed, on how aspects of design constrain their ecological performance, and into how aspects of design in one physiological system can impose limits on other systems. The osmoregulatory processes of nectar-eating birds highlight the relevance of understanding the impact that events taking place in the gut can have for feeding behavior, and renal and metabolic function. Adopting a broadly comparative approach to understanding the interaction between feeding behavior, digestion, and osmoregulation is pertinent because is unclear whether the many extreme physiological characteristics of hummingbirds that have traditionally been assumed to be associated with a nectar-feeding habit are shared by other nectar-eating birds. In my dissertation research I have begun to examine the similarities, and have found some important differences, in the responses of two major radiations of nectar-eating birds to their sugary and watery diets. Read more
|
Page generated in 0.0354 seconds