No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Cold-water corals increase habitat heterogeneity and enhance biodiversity in deep waters worldwide. Despite the recognition of their importance in the deep sea, limited data exist on the ecology and evolution of deep-water corals. The overarching goal of this dissertation research was to integrate molecular, morphological, and ecological data to understand the degree to which populations are connected, species are distributed, and communities are assembled in the deep (250-2500 m) Gulf of Mexico (GoM). Specifically, several hypotheses were tested regarding the roles of environmental variables, particularly depth, influencing population and community structure. Combining phylogenetic and population genetic approaches with ecological data enabled species delimitations of many taxa while demonstrating that deep-water populations and communities diverge over short bathymetric distances. It appears that population isolation, congeneric species replacement and changes in community composition occur rapidly with depth, and these changes are likely due to a combination of both dispersal limitation and adaptive divergence with depth. Local self-recruitment may also be strong within any one site. Furthermore, results suggest that evolutionary history and neutral dynamics play a critical role in octocoral community assembly in the deep sea. This dissertation not only contributes a substantial amount of evolutionary and ecological information on a poorly studied group of foundation species in the deep sea, this research has broader implications for aiding in efforts to protect these long-lived, foundation species from anthropogenic disturbances. / Biology

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 304-324). Available also in a digital version from Dissertation Abstracts.

Humans have tried to separate themselves from nature and to gain an understanding of what it means to be human, through studies of nature. Ideas of human nature have political and ideological implications, and are thus important in providing information about what it means to be human and what the relation to animals and the environment "ought" to be like. The ideology of human nature makes the world hence meaningful and points out what kind of actions regarding environmental issues are appropriate. The understanding of human nature and the human relationship with nature is culturally and historically produced. Humans' cultural conception thus also influences what kind of relationships are seen as desirable with particular animals. Different animals are seen as having different relations to humans, relations in which all animals are not seen as being equal. Some animals are defined edible, others are defined as companions.