Microevolutionary Response in Lower Mississippian Camerate Crinoids to Predation Pressure

Crinoids were relatively unaffected by the end-Devonian Hangenberg event, but the major clades of Devonian durophagous fishes suffered significant extinctions. These dominant Devonian fishes were biting or nipping predators. In response to the Hangenberg event, Lower Mississippian crinoids underwent an adaptive radiation, while fish clades with a shell-crushing durophagous strategy emerged. Durophagous predators are inferred to have been more effective predators on camerate crinoids and it is hypothesized that through the Lower Mississippian, camerate crinoids evolved more effective anti-predatory strategies in order to compensate for the more effective predatory strategy of the durophagous fishes. More convex plates and longer spines are commonly regarded to provide more effective anti-predatory strategies. Did convexity and spinosity increase among camerate crinoids during the Lower Mississippian? A new method was formulated to test for an increase in convexity of the calyx plates among species of the genus Agaricocrinus. Spine length was analyzed in the genera Aorocrinus and Dorycrinus and is a simple linear measurement standardized to calyx diameter. Data were analyzed using Kolmogorov-Smirnov and Mann-Whitney U tests to determine if morphological change was statistically significant. Dorycrinus showed the most significant evidence for directional change through time, which provides evidence for escalation as a response to fish predation. Aorocrinus seemed to most likely display stasis or a random walk, whereas Agaricocrinus did not show evidence for distinct directional evolution, but rather showed a decrease in variance in convexity values through time.Shell Exploration and ProductionThe Ohio State Arts and Sciences Honors ProgramA five-year embargo was granted for this item.Academic Major: Earth Science

Market segmentation analysis

INTRODUCTION This working paper presents the findings of research aimed at assessing differences in the value of time by market segment. It draws on findings presented in AHCG’s final report to DETR (AHCG, 1996) and previous research conducted during the course of this research contract (Bates and Whelan, 2001) and it is intended that this document be read in conjunction with those two reports. The paper describes the estimation of a base model for each journey-purpose (business, commuting and other) and shows how each is influenced by: income, journey distance, cost reimbursement, congestion, vehicle occupancy, trip sub-purpose, occupation, age group, gender, household type, ‘free time’, respondent type, time constraints and geographical region. The findings of this analysis are then drawn together to develop a final set of models that allow the value of time to vary across a range of market segments. All models are estimated using GAUSS (Aptech Systems) without taking account of the repeat observations nature of the stated preference data

THE COST OF MEETING EQUITY: OPPORTUNITY COST OF IRRIGATION IN THE FISH-SUNDAYS SCHEME OF SOUTH AFRICA

In this paper the incremental values of water are calculated for irrigators in the Fish-Sundays Scheme of South Africa's Eastern Cape province. The socio-political pressure for redistribution of agricultural resources provided the imperative for this study. The model of the Fish-Sundays Scheme reflects a survey of 50 000ha of fodder and citrus production. It explicitly models the water demand on sixteen typical farms, for five irrigation technologies, six crops and four livestock activities. The existing allocation generates an average value of R0.0423/m3/year, which increases to R0.0681/m3/year if farmer-to-farmer trading is allowed given existing infrastructure. Unrestricted trade raises the average value to R0.0719/m3/year. The marginal cost of additional water in the source basin is R0.05/m3/year for the first 315 million m3 and R1.27/m3/year to extend capacity beyond that.water value, irrigation, linear programming, South Africa, Eastern Cape, Resource /Energy Economics and Policy, Q15, Q12,

Trade Sanctions, Financial Transfers and BRIC's Participation in Global Climate Change Negotiations

Countries can reduce global emissions by reducing own consumption since they are linked to the total value of consumption world wide. Two effects are at issue: a utility loss from forgone consumption and a utility gain from lowered temperature change. It is thus unclear whether own country emissions reductions are in the self interest; typically they are not for small countries, but may be for larger countries. Here are investigate the incentives for individual large population low wage rapidly growing countries in the BRIC group (Brazil, Russia, India, China) and the groups of countries as a sub-global coalition. We also assess what level of other countries’ trade measures linked to non participation is needed to induce compliance as an all or nothing discrete choice. We capture induced changes in the global trade equilibrium in our analysis, as well as participation linked to financial transfers. Our results suggest that only very high tariffs over a hundred percent by all other countries, or even higher tariffs by the OECD alone, could induce participation by BRIC countries, especially when the country is a net exporter. Equally, large financial transfers would be needed.trade sanctions, financial transfers, global emissions, climate change

On the measurement of ecological novelty: scale-eating pupfish are separated by 168 my from other scale-eating fishes.

The colonization of new adaptive zones is widely recognized as one of the hallmarks of adaptive radiation. However, the adoption of novel resources during this process is rarely distinguished from phenotypic change because morphology is a common proxy for ecology. How can we quantify ecological novelty independent of phenotype? Our study is split into two parts: we first document a remarkable example of ecological novelty, scale-eating (lepidophagy), within a rapidly-evolving adaptive radiation of Cyprinodon pupfishes on San Salvador Island, Bahamas. This specialized predatory niche is known in several other fish groups, but is not found elsewhere among the 1,500 species of atherinomorphs. Second, we quantify this ecological novelty by measuring the time-calibrated phylogenetic distance in years to the most closely-related species with convergent ecology. We find that scale-eating pupfish are separated by 168 million years of evolution from the nearest scale-eating fish. We apply this approach to a variety of examples and highlight the frequent decoupling of ecological novelty from phenotypic divergence. We observe that novel ecology is not always tightly correlated with rates of phenotypic or species diversification, particularly within recent adaptive radiations, necessitating the use of additional measures of ecological novelty independent of phenotype