A Sample Critique Paper

Critique paper "Teeth, Brains, and Primate Life Histories"

The nature of relationships among dental development, somatic development, skeletal development, and life history is complex. The timing of dental development is not related to species-level differences in brain and body size, but it is relative to somatic and cranial growth. Teeth grow increasingly and preserve within them a record of that increasing growth in the form of microscopic growth lines. Studying dental development in extinct primates, and its relationship to adult brain and body size as well as other life history and ecological parameters ( diet, somatic growth rates, gestation length, age at weaning), holds the potential to yield unparalleled insights into the life history profiles of fossil primates. Using reconstructions or estimates of adult body mass, brain size, and diet in Primates, as well as the eruption sequence of its permanent teeth, it explored the efficacy of these variables in predicting the absolute pace of dental development in this fossil species. Brain size is the best single predictor of crown formation time in primates, but other variables help to explain the variation.

Critique of the Article Focus The title of the paper is "Teeth, Brains, and Primate Life Histories" by Laurie R. Godfrey, K.E. Samonds, W.L Jungers, and M.R. Sutherland. The title itself of the research paper already gives the summary and overview of the whole study. It attracts the interest of the readers on the relationship between Dental development and other variables. Background The study has been created in order to determine the role of brain size, body size, age at weaning, and age at first female breeding that are more commonly considered in studies of mammalian life history variation. The task is not to test competing explanations of life history variation. Rather, it focuses on the variables that serve as a possible correlates of variation in primate dental development. Terms of Reference The objectives of Godfrey are to find out the effects of brain and body development, protein consumption, dental precocity with dental development and also to determine if there is a correlation between those mentioned above and the variables such as age at weaning, body size, brain size and diet, moreover this paper is aimed to find out the association among variables and dental development.

Study Design In the study conducted by Godfrey, the researcher used the qualitative method in measuring the relationship among species, dietary category, immature individuals and mature individuals, as well as the variables such as age at weaning and first breeding, diet, brain size, etc. Sample Data eruption and metric data were collected by K.E.S. and L.R.G. on 900 individuals belonging to 40 species in 11 families of nonhuman primates. Collection of dates for wild-caught lemurs, coat characteristics for colobines and some new world monkeys, and body masses of wild-caught and captive individuals belonging to species whose growth increase overtime. The result was a reconstruction of at least partial eruption schedules for the primate species. Life history data were compiled from the primary literature. For each individual mesiodistal and buccolingual diameters were measured. The sample of measured crania are given in which the dietary category includes insects, fruits, and foliage or seeds. For the data analysis the author specify the predictions of each of the hypothesis using shared and unique contributions of explanatory variables. A table was given as a summary of the predictions of each of the six hypotheses and their corresponding statistical tests. Directional hypothesis is tested using one tailed probabilities and non-directional hypothesis is tested using two tailed probabilities. It is the unique predictions of each hypothesis that are most critical to hypothesis testing. Hypothesis In this study the researcher tested six hypotheses. Two link developments to aspect of adult size and four relate development to diet. The design constraint hypothesis: generally talks about the measurement of development between large –bodied species and small-bodied species The brain pleiotropy hypothesis: cranial capacity should predict age at weaning and first breeding. Dental development may prolong as an incidental effect of prolonged brain growth. The foraging independence hypothesis: this is a logical derivative of what has been called “need to learn” hypothesis, which purports to explain the observed correlation between large brain size and delayed reproduction. The risk aversion hypothesis: the premise of this hypothesis is that resource distribution and abundance co varies with diet, and affects the risk of starvation.

The food processing hypothesis: the premise of this hypothesis is that the mechanical requirements of mastication co vary with diet. The protein richness hypothesis: the premise of this hypothesis is that, because protein is essential for growth, the relative amount of protein in the diet influences rates of growth and development.

Data Presentations The author has used tables to present the statistical data of the research. Tables for the test of risk aversion hypothesis, test of food processing hypothesis, and the test of protein richness hypothesis. In addition the results for the test of dental precocity at weaning and age at weaning were also presented in the form of graphs. Main Findings The study has determined that adult body size fares poorly in comparison to brain size which is considered the best predictor of dental development precocity at 4 months and 1 year. There is also little or no comparison between age at first breeding and the pace of dental development, once the effects of body size is controlled. Mechanical requirements for food processing also affect dental development at weaning. Species feeding on large amounts of insects, seeds, or foliage develop quickly. However, these species are also typically either small-bodies or small-brained. The ratio of dental development at weaning to age of weaning co varies inversely with brain and body size in primates. Conclusion and Recommendation In the study it has shown that there are correlations between the brain size, diet and dental development in primates and that its independent of body size, age at first breeding, and cranial capacity.