Growth rates and phylogeny in primates

Abstract

There is sufficient evidence to indicate that man grows for a longer period of time than chimpanzee who in turn has a greater duration of growth than rhesus monkey. The problem of this paper was to determine if there was a concomitant decrease in a rate of growth. Using the relative growth rate of Fisher ('21), it appears that for most of their period of growth, the rate of change is the same. Immediately after birth, when we have no data for children, rhesus monkey grows significantly faster than chimpanzee. By a year and a half their rates are the same, and neither species shows a sex difference. From seven years (age of youngest children) until children start through puberty, there is no sex difference in Homo sapiens, and the human rate does not differ from the chimpanzee rate. Because of the resemblance between the primate curve for rate and that for dairy cattle, it is postulated that this curve is more mammalian than primate and that during phylogeny the primates have merely increased the duration of time when growth is possible. Man does show one new feature, the puberal growth spurt, which is not found in the non-human data considered.The implications of these conclusions for primate phylogeny and for growth are discussed.

Development and sexual selection in primates

“…Using mixed longitudinal and crosssectional body mass data for 37 species of captive primate, he showed that, as predicted from patterns of adult size dimorphism, species with low levels of inter-male competition do not show sex differences in development (monogamous / polyandrous mating systems). Where it occurs, adult sexual size dimorphism can arise via sex differences in the duration of growth (sexual bimaturism), by differential growth rates in the two sexes, or by a combination of the two (Gavan & Swindler, 1966;Shea, 1986). These different ontogenetic trajectories, bimaturism (male time hypermorphosis) and differential growth rates (male rate hypermorphosis), can none the less produce similar levels of adult dimorphism observed in relatively closely-related species (Leigh, 1992).…”

The Developing Dentition and Tooth Structure in Hominoids

“…Nonethe less, it seems that this tooth has also been found to be mineralizing in newborn and stillborn great apes and macaques, once again suggesting identical relative timing of dental developmental events within the hominoid growth period. Gavan and Swindler [3] and Swindler [4] have empha sized this point in a comparison of both gen eral growth and the developing dentitions of modern humans, great apes and macaques, drawing attention to the mineralization and emergence of molar teeth in these groups at similar proportions through the growth peri od. Recently, Smith [5] investigated the rela tionship between several life history vari ables and dental development in primates.…”

Molar development in common chimpanzees (Pan troglodytes)

“…Hominoid dental development and tooth emergence have historically been valued because they offer insight into theories of life history and phylogeny (Zuckerman, 1928;Krogman, 1930;Schultz, 1935;Bennejeant, 1940;Clements and Zuckerman, 1953;Gavan and Swindler, 1966;Gavan, 1967), as well as the absolute ages of individuals that are still developing their dentitions (e.g., Garn et al, 1959;Bailit, 1976;Dean and Wood, 1981;Smith et al, 1994).…”