Phylogenic Evidence of Tarsiers as Anthropoids Essay

Phylogenic Evidence of Tarsiers as Anthropoids - Essay Example However a number of shared and less similar characters make definitive decision about direct ancestors of present day tarsiers almost impossible. There have been considerable debate and research over the tarsiers' relation to prosimians and anthropoids. A number of anatomic and molecular biological studies in recent times have shown a number of derived traits in tarsiers similar to anthropoids. Pocock in 1918 was the first to suggest an anthropoid connection to tarsiers based on its numerous shared derived traits or morphological synapomorphies and allocating it to the sub-order Haplorhini. Based on the data from Gursky (1999) tarsiers share conspicuous haplorhine traits such as a dry rhinarium, haemochorial placentation, reduced olfactory bulbs, promontory artery, fovea centralis and a flexible upper lip. However there are inconsistent views on these traits being purely anthropoidean as it is also argued that the traits have been attained due to homoplasy because of its nocturnal tropical niche over long time periods (Barrett and Dunbar, 2000). The visual system of tarsiers show high ganglion cell densities, high orbital convergence, retinal fovea, postorbital septum and lack tapetum lucedum which shows a stem lineage leading to a tarsier-anthropoid clade (Ross, 2000). Studies have implicated tarsiers to be derived from diurnal ancestors as in haplorhine primates, primarily due to the fact that they have lost the reflecting layer in the eye tapetum lucidum that maximizes its light gathering capacity. Comparison of the average measurement of eye and cornea diameter and ratio of these measurements in relation to the average body weight among primate specimens were considered by Jason Cowan in his attempt to solve the phylogenetic enigma. The eye and cornea diameter averages were closest to the anthropoidean relative Aotus. However the average eye diameter with respect to the average body length showed a prosimian connection. However it could be adaptations for nocturnal habitation and specific dietary reliance that require high visual acuity (Cowan, 2006). A diet reconstruction through character optimization shows a fruit and insect diet for the haplorhine stem lineage and visual predation on insects an adaptation of this (Ross, 1996). Another plausible scenario is that of a nocturnal tarsier like ancestry to anthropoids which occurred when a lineage diverged to adopt diurnality (Cartmill, 1980). Auditory System Tarsiers and anthropoids share an unusual feature in the petrous temporal bone which is the anterior accessory cavity. The cavity arises from the bony auditory tube as a pneumatic diverticulum ontogenetically and invades the developing petrosal plate it into a medial and lateral lamella that forms wall of the auditory bulla and tympanic cavity respectively (Cartmill&Kay, 1978, MacPhee & Cartmill 1986). The two chambers in the middle ear augment sensitivity to low and high frequency sound (Lomabard and Hetherington, 1993) that aid small nocturnal primates in visual predation. Brain components Analysis of brain components of tarsiers by comparing it with both anthropoid primates and prosimians showed a clear anthropoid connection in the work done by Joffe and Dunbar (1998). An increase in size of the visual brain components as a result of encephelization

World Hunger Essay Example | Topics and Well Written Essays - 500 words - 1

World Hunger - Essay Example Poor countries that are in the process of developing do not have enough economic reserves and human capital to provide for the sustenance of their population. Furthermore, they are made to export their few assets particularly their natural resources that leads to a reduction in their capital stock. Also, investors ignore developing countries because they cannot produce feasible profits due to lack of infrastructure. Thus, major businesses do not invest their capital in the developing countries and without the investment, the productivity ceases to increase. Cycle of economic distress keeps the countries in a permanent stage of poverty and under development. Developing countries all around the globe basically lack the general infrastructure that is important for these countries to rise above the economic deficiency that is the leading cause of hunger. The general infrastructure includes a solid road system, warehouses and good irrigation systems and the lack of these causes an increase in transport expenses, deficient facilities for storing and poor water supplies. This limits the average farming produce and hence results in a lower amount of food being available. Considering the major problems, the answer to hunger is building reliable systems of energy, effective means of transportation and communication. This would provide incentives to the potential investors and hence result in generation of capital in the developing nations. Economic growth is possible by the investments coming from the private sector. Business activities increase proportionally to the growth of investment which in term increases the productivity as well as the distribution of goods. This assists in the satisfaction and fulfillment of the common people. In the underprivileged areas of the world, for example the sub-Saharan Africa, poor geographical location and political turmoil has led to small and unreachable