No description available.

No description available.

Ecological speciation involves the evolution of reproductive isolation (RI) as a by-product of adaptation to different selective environments. Parallel patterns of non-random mating by environment type provide strong evidence that ecological speciation has occurred. The processes involved in the origins of RI are more difficult to detect however. One mechanism involves the correlated evolution of mating preferences and sexually selected traits. I developed a conceptual model for detecting RI under various scenarios of mate preference evolution. The model predicts that RI will not evolve if preferences are evolutionarily constrained relative to the preferred traits, but is detectable as long as preferences evolve in parallel. I then applied this framework to an empirical system with populations of guppies (Poecilia reticulata) adapted to low- and high-predation environments. I measured female mate preferences for male colour and size; traits which are divergent between the two environment types. Preference functions for colour also diverged in the predicted direction. The parallel pattern of preference divergence suggests that divergent natural selection from predators may be contributing to RI between guppy populations.

Thesis (D.L.S.)--Columbia University, 1992. / Includes bibliographical references (leaves 123-145).

Thesis (D.L.S.)--Columbia University, 1992. / Includes bibliographical references (leaves 123-145).

No description available.

No description available.

<p>This study examines the advent of state public health and medical services in Trinidad in the post-emancipation colonial period, to 1916. Britain's sugar-producing plantation societies were structured to allow the small white Creole plantocracy to exploit the labour of the African and East Indian lower orders and keep the people in a perpetual state of poverty. Trinidad established the Government Medical Service (GMS) in 1870 in response to an edict from the Colonial Office. The civilising mission had clearly gone awry and state-provided western medical services would henceforth be mandatory to mitigate the excessive mortality and morbidities amongst the subject peoples.</p><p>The GMS rapidly evolved into a major provider of medical care services. However, the form and function of the GMS remained contested terrain, due to the enduring disagreements about the causes of the widespread impoverishment and illhealth amongst the people. The Creole plantocracy used the poverty and poor health of the Africans as proof of their regression into barbarism after emancipation. Conversely, some British officials believed that plantation society colonialism created adverse conditions of life, thus obligating the state to alleviate its effects. The Afro-and IndoTrinidadian people emerged as a powerful force in the process of creolising the colonial state's social policies, as tens of thousands of sufferers sought assistance from the government doctors each year. The GMS thus developed as a distinctly creolised West Indian entity providing western public health and medical services to the African and East Indian residents.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.