Moral philosophy: A biological approach

In this paper I argue that Darwinian evolutionary theory gives us the key to an adeguate understanding of morality. Althougt in the past the naturalistic fallacy has been thought to be a bar to the application of evolution to ethics I suggest that properly viewed evolutionary ethics can avoid this problems.     

Moral philosophy and public policy: the case of NRTs

In this paper, I will express some reservations about the usefulness of moral philosophy for the analysis of public policy issues.... My question is whether taking morality seriously requires taking moral philosophy seriously. This paper focuses on one particular public policy context -- namely, government commissions into new reproductive technologies, such as Britain's Warnock Committee, Australia's Waller and Michael Committees, Canada's Baird Commission, and many others.... Moral philosophers are sometimes asked to participate in these commissions, either as Commissioners, staff, or expert advisers. How can moral philosophers contribute to the analysis of public policy recommendations on NRTs? A survey of the literature suggests that there are two main views on this question, one of which is ambitious, the other more modest. The ambitious view says that moral philosophers should attempt to persuade Commissioners to adopt the right comprehensive moral theory (e.g. adopt a deontological theory, rather than utilitarianism or contractarianism), and then apply this theory to particular policy questions. The more modest view shies away from promoting a particular moral theory, given that the relative merits of different moral theories are a subject of dispute even amongst moral philosophers. Instead, it says that moral philosophers should attempt to ensure that the Commission's arguments are clear and consistent. On this view, philosophers should focus on identifying conceptual confusions or logical inconsistencies within the Commission's arguments without seeking to influence its choice of the underlying theory.     

Great ape societies

Edited by W.C. McGrew, Linda F. Marchant, and Toshisada Nishida. New York: Cambridge University Press. 1996. 328 pp. ISBN 0-521-55494-2. $64.95 (cloth). © 1998 Wiley-Liss, Inc.     

African ape ancestry

It is commonly believed that the australopithecines are more closely related to humans than to African apes. This view is hardly compatible with the biomolecular data which place theHomo/Pan split at the beginning of the australopithecine period. Nothing in the fossil hominid morphology precludes the possibility that some australopithecines were ancestral to gorillas or chimpanzees and others to humans.     

Primatology: advanced ape technology

New findings from African rainforests show chimpanzees to have impressively advanced technology. They make tools of vegetation to harvest termites as in East and West Africa, but some apes in Central Africa show different techniques and tool sets geared for different tasks.     

A naked ape would have fewer parasites

Unusually among the mammals, humans lack an outer layer of protective fur or hair. We propose the hypothesis that humans evolved hairlessness to reduce parasite loads, especially ectoparasites that may carry disease. We suggest that hairlessness is maintained by these naturally selected benefits and by sexual selection operating on both sexes. Hairlessness is made possible in humans owing to their unique abilities to regulate their environment via fire, shelter and clothing. Clothes and shelters allow a more flexible response to the external environment than a permanent layer of fur and can be changed or cleaned if infested with parasites. Naked molerats, another hairless and non-aquatic mammal species, also inhabit environments in which ectoparasite transmission is expected to be high, but in which temperatures are closely regulated. Our hypothesis explains features of human hairlessness-such as the marked sex difference in body hair, and its retention in the pubic regions-that are not explained by other theories.     

What we don't know about great ape variation

The patterning of intraspecific variation among the great apes is proving more complex than has been recognized previously. The great ape species, as currently defined, may include markedly different subspecies, alternatively, the majority of intraspeclflc variation may be observed at the populational level within a single subspecies. Recent studies have raised a number of questions about great ape evolutionary biology. How many species of living great apes exist? What was the original dietary adaptation of gorillas? How should we define male orang-utan adulthood?     

Experimental field studies of Asian ape social systems

The Asian apes, orangutans and gibbons, possess unusual social systems among anthropoid primates. Social groups of gibbons consist of mated adult pairs and their offspring; mature orangutans are primarily solitary. Recent experimental field research has begun to yield insights into the behavioral mechanisms employed by these animals to maintain their characteristic patterns of social dispersion. While spatial separation between female orangutans appears to be maintained passively, aggression, which is manifest during direct encounters and long-distance vocal interactions, mediates male asociality. Male-male aggression is the result of intense intrasexual competition occurring between animals for mating access to females. To reduce intrasexual competition, male orangutans have adopted alternative mating tactics. In contrast to female orangutans, female gibbons show marked agonistic tendencies toward conspecifics. Female territoriality contributes to preventing males from becoming polygynous. Male gibbons, restricted to monogamous relationships, attempt to ensure their paternity through intrasexual aggression. These observations suggest that the spatial dispersion of females constrains male mating options in both species. However, variations between orangutan and gibbon social systems can be understood as consequences of the temporal dispersion of sexually receptive females. The temporal clumping of females, due to relatively high operational sex ratios, limits the ability of male gibbons to acquire multiple mates. Conversely, an extremely low operational sex ratio in orangutans creates a strong selection pressure for intrasexual competition and polygamous mating. These considerations provide a novel framework for interpreting the social systems of the African apes.     

Non-nutritive sucking in great ape and human newborns

The development of non-nutritive sucking in chimpanzee, orangutan and human newborns was observed during the first days of life. The group of ten human subjects reliably increased their rate of sucking, time spent sucking, and number of sucks per ten-minute testing session during days 1–4. Similarly, the group of four newborn chimpanzees demonstrated increases in these same measures. The data from the two orangutan subjects, although not statistically significant, were generally consistent with that of the other newborns. The stability of the sucking response and the pattern of sucking were the major apparent between-species differences. The human newborns sucked in a stable pattern of bursts and pauses beginning on day 1, whereas the chimpanzee and orangutan subjects gradually developed a pattern of relatively continuous sucking. The disruptibility of the sucking response was tested using a five-second auditory stimulus. Disruption occurred 58% for humans, 40% for chimpanzees, and 20% for orangutans. It was concluded that non-nutritive sucking of great ape newborns is less distractible by external stimulation than that of human newborns. This apparent rigidity makes it a less useful dependent variable in studies of the sensory capacities of chimpanzee and orangutan newborns than was predicted.     

Clastogenic activity of sodium fluoride in great ape cells

Conflicting evidence has been reported concerning the mutagenicity of sodium fluoride (NaF), especially clastogenicity at concentrations of more than 1 mM. NaF is known to induce chromosome aberrations at these concentrations in human cells, but not in most rodent cells. We considered that such species-specific difference in chromosomal sensitivity would be derived from the phylogenetic distance between rodents and man. To clarify the role of interspecies differences, we investigated the chromosomal sensitivity to NaF in cell lines from various primates, which diverged into many species, including rodent-like prosimians and human-like great apes. The results showed that the clastogenicity of NaF was limited to human and great ape cells.     

High mutation rates in human and ape pseudoautosomal genes

It has been suggested that recombination may be mutagenic, which, if true, would inflate intraspecies diversity and interspecies silent divergence in regions of high recombination. Here, we test this hypothesis comparing human/orangutan genome-wide non-coding divergence (K) to that in the pseudoautosomal genes which were reported to recombine much more frequently than the rest of the genome. We demonstrate that, compared to the average human/orangutan non-coding divergence (K=3%), the substitution rate is significantly elevated in the introns of SHOX (K=5.7%), PPP2R3L (K=8.7%) and ASMT (K=6.5%) genes located in the human and orangutan Xp/Yp pseudoautosomal region (p-PAR), where recombination is over 20-fold higher than the genomic average. On the other hand, human/orangutan non-coding divergence at the Xp/Yp pseudoautosomal boundary (K=3.5%) and in the SYBL1 gene (K=2.7%), located in the human Xq/Yq pseudoautosomal region (q-PAR), where recombination is known to be less frequent than in p-PAR, was not significantly higher than the genome average. The data are consistent with the hypothesis that recombination may be mutagenic.