Reconsidering the null hypothesis: Is maternal rank associated with birth sex ratios in primate groups?
AUTOR(ES)
Brown, Gillian R.
FONTE
National Academy of Sciences
RESUMO
Trivers and Willard hypothesized that vertebrates adaptively vary the sex ratio of their offspring in response to the mother's physical condition [Trivers, R. L. & Willard, D. (1973) Science 179, 90–92]. This hypothesis has produced considerable debate within evolutionary biology. Here we use meta-analysis techniques to evaluate claims that nonhuman primate females facultatively adjust the sex ratio of their progeny in relation to their own dominance rank in a uniform way. The magnitude of the difference in birth sex ratios of high- and low-ranking females declines as sample sizes increase, and the mean difference in birth sex ratios of high- and low-ranking females is zero. These results suggest that the observed effects could be the product of stochastic variation in small samples. These findings indicate that presently we cannot reject the null hypothesis that maternal dominance rank is unrelated to birth sex ratios.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=123242Documentos Relacionados
- Maternal Age and Birth Rank in the Aetiology of Mongolism
- Association of Congenital Malformation of the Heart with Birth Rank and Maternal Age
- Hypothesis: "Rogue cell"-type chromosomal damage in lymphocytes is associated with infection with the JC human polyoma virus and has implications for oncopenesis.
- Hypothesis: Lipoprotein(a) is a surrogate for ascorbate
- Hypothesis: lipoprotein(a) is a surrogate for ascorbate.
