Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!uwvax!uwmacc!uwmcsd1!csd4.milw.wisc.edu!duncan From: duncan@csd4.milw.wisc.edu (Shan D Duncan) Newsgroups: sci.bio Subject: Re: Bushmen Message-ID: <2453@uwmcsd1.UUCP> Date: Sat, 11-Jul-87 15:23:50 EDT Article-I.D.: uwmcsd1.2453 Posted: Sat Jul 11 15:23:50 1987 Date-Received: Sun, 12-Jul-87 16:47:09 EDT References: <4505@ihlpa.ATT.COM> Sender: daemon@uwmcsd1.UUCP Reply-To: duncan@csd4.milw.wisc.edu.UUCP (Shan D Duncan) Organization: University of WI-Milwaukee Lines: 50 In article <4505@ihlpa.ATT.COM> krista@ihlpa.ATT.COM (K.J.Anderson) writes: >which claimed that the Bushmen are genetically different from other >people in the following ways: > >a) A camel like hump adapatation, for water storage, >b) Sterile offspring from marriages to other groups, >c) Over 50% of the population has number of chromosomes not = 46. > >Because I've read several books about anthropology and never heard [ List several reasons for the low birth rate among the Bushmen (and women :-) ) ] > >a) "[Bushmen]...are extremely hardy: the fat on the women's buttocks >and thighs is a reserve for lean times, > >b) "There is another possible reason why families are small. >According to the Bushmen themselves their women are naturally >sterile during the dry season." [1] Here again, note that cessation >of menses is not uncommon among female professional athletes >ihnp4!ihlpa!krista - I can't help it, I'm just a baby ape. Add to his points above. The reason I heard for the cessation of menses among female athletes is a very low body fat percentage (the estrogens being STEOIDS and fat soluble... perhaps?). Bushmen tend to nurse their offspring for what we westerns consider to be a long time (2-3 years). In many cases this can act as a form of birth control (continued elevated oxytocin levels). Finally humans are not very fertile to start about 30% under the "best" conditions. To compare most farm animals are about 80%. This is not unusual since humans have a relatively long breeding life span and infant care last an fairly long time. [ These properties were once refered to as K-selected atributes... ]. So. All in all there really is only one species of human alive today using the Biological Species Concept (Actually the Zoological Species Concept). --------------------------- duncan@csd4.wisc.milw.edu | ---------------------------