Browsing by Subject "Life history"
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Item Autecological effects of habitat alteration: Trophic changes in mangrove marsh fish as a consequence of marsh impoundment(Elsevier, 2008) Kemp, Stanley J.The key to predicting, counteracting, and managing environmental change is understanding the mechanisms through which habitat change affects populations of organisms. The mangrove ecosystem of the Indian River Lagoon (IRL), east-central Florida, has been impounded for the purpose of mosquito control and is representative of such large-scale alterations. Sailfin mollies Poecilia latipinna in this system exhibit significant interpopulation differences in adult body size in relation to habitat alteration. One likely hypothesis for this pattern is the apparent change in diet experienced as a result of impounment, as has been documented in earlier studies. To address the question of whether these dietary changes would have been sufficient to cause trophic differences in P. latipinna populations relative to impoundment, a comparative study of trophic position in 2 size-divergent populations of P. latipinna using stable isotopes was employed. Results suggested that P, latipinna from an unimpounded site had a slightly higher trophic position than those from an impounded site and may constitute a partial explanation of differences in adult body size between the 2 populations. Results from the present study also showed that there was a fundamental difference in energy source between the study sites, which suggests greater assimilation of mangrove-based carbon in impoundments. Specific population- and community-level effects of impoundment on mangrove habitats have been demonstrated, indicating a mechanistic link between anthropogenic habitat alteration and life history of P. latipinna.Item Does the thought of death accelerate a fast life history strategy?: Evaluating a mortality salience prime(2016) Frederick, Michael; Khan, Humama; Ancona, MatthewThe characteristics of the developmental environment can have long-term effects on an individual's metabolism, stress-sensitivity, hormone levels, and gene expression. Life history theory suggests these outcomes can be broadly viewed as individual strategies along a continuum from 'fast' to 'slow', with stressful environments predisposing individuals towards faster, more short-term oriented strategies. Griskevicius et al. (2011a) reported an interaction between childhood socioeconomic status and a mortality prime when measuring economic impulsivity using a delay-discounting task. Specifically, participants who grew up in wealthier homes responded to a mortality prime by becoming less impulsive, while those who grew up less wealthy reacted to the prime by becoming more impulsive. The current study sought to replicate and expand upon these findings using a sample of university undergraduates (66 females and 19 males). Participants were exposed to a mortality prime, an anxiety prime, or a neutral prime before completing a questionnaire that included questions about childhood socioeconomic status and a delay discounting survey. When the results of the delay discounting measure were analyzed, no significant interaction between childhood environment and priming condition was observed. Thus, we failed to replicate the findings of Griskevicius et al. (2011a). We suggest that the limited saliency of the mortality prime may account for this discrepancy, and note that the results of other priming studies have often been difficult to replicate. Limitations and future directions for priming studies and life history research are discussed.