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dc.contributor.advisor Cartmill, Matt en_US
dc.contributor.author Barrickman, Nancy Lynn en_US
dc.date.accessioned 2009-01-02T16:24:44Z
dc.date.available 2009-01-02T16:24:44Z
dc.date.issued 2008-09-18 en_US
dc.identifier.uri http://hdl.handle.net/10161/892
dc.description Dissertation en_US
dc.description.abstract <p>The pace of life history is highly variable across mammals, and several evolutionary biologists have theorized that the tempo of a species' life history is set by external factors. These factors, such as food availability and predation pressure, determine mortality rates. In turn, mortality rate determines the age at maturity. High mortality rate results in early age at maturity; individuals must grow and reproduce quickly because of the high risk of death. Conversely, a low mortality rate is allows individuals to prolong their growth period and reproduce slowly. This theory assumes that growth rates are constant across species, and thus body size is determined by mortality rates.</p><p>This project posits that the intrinsic characteristics of species set the pace of life history. Among anthropoids, there is a great deal of variation in growth rates and the pace of life history relative to body size. The hypotheses proposed by this project state that the degree of encephalization in a species determines the growth rates, the length of the growth period, and the adult lifespan. Growing a large brain is costly and requires a prolonged period of development. However, a large brain has the benefit of reducing mortality by facilitating cognitive strategies for food procurement and predator avoidance. This cost/benefit balance results in the pattern of life-history variation in which mortality rates are correlated with the length of the growth period. However, the causal arrows are reversed; instead of the mortality rate determining the age at maturity and consequently the size of the species, the relative brain size of the anthropoid determines the mortality rate and the age maturity.</p><p>These hypotheses were tested by determining the body and brain growth trajectories of thirteen anthropoids, and compiling life-history data from long-term studies of these species in the wild. Multi-variate analyses demonstrated that extensive brain growth, whether through prolonged duration or rapid growth rates, results in slow body-growth rates during the juvenile period and delayed age at maturity. In addition, encephalization results in longer adult lifespan. Therefore, this project demonstrated that intrinsic characteristics of anthropoid species determine the pace of their life histories.</p> en_US
dc.format.extent 4935943 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject Anthropology, Physical en_US
dc.subject Biology, Zoology en_US
dc.subject life history en_US
dc.subject ontogeny en_US
dc.subject brain size en_US
dc.subject encephalization en_US
dc.subject anthropoid evolution en_US
dc.title Evolutionary Relationship between Life History and Brain Growth in Anthropoid Primates en_US
dc.type Dissertation en_US
dc.department Biological Anthropology and Anatomy en_US
duke.embargo.months 12 en_US
dc.date.accessible 2009-09-18T05:00:02Z

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