LIFESCI 15 Lecture Notes - Lecture 13: Nuptial Gift, Lactation, Standard Deviation
2/22/18
- Example 4: testosterone
o Stimulate growth and maintenance of male reproductive systems
o Stimulate 2 sex characteristics:
▪ Hair growth
▪ Low voice
▪ Muscle mass
o Numerous effects on mood and behavior
Hormones influence behavior
- Observations of testosterone
o Songbird mating: increased T leads to increased RS but also higher mortality
▪ Males set up territories and females pick the territories they like
▪ Researchers implanted a tube that would release testosterone
▪ The males who had the testosterone implanted fought longer for territories → better
reciprocity
▪ Mortality rates were higher, susceptible to infections etc.
▪ Lifetime fitness was shorter
o Rat maze learning
▪ Males better than females only during high testosterone season
▪ During non-breeding season ale’s testes get sall ad do’t produe a lot of
testosteroe so the differee etee testosteroe i ales ad feales, ales do’t
outperform females
▪ During breeding season ale’s testes get larger and do better than females
o Tennis battles
▪ Prior → oth gus’ T rises
▪ After → loser’s plueted ad ier’s shot up
▪ In both guys who were playing prior to the match their testosterone levels were high
▪ After the match who guy who won maintained the high level of testosterone while the
guy who lost his testosterone level plummeted
▪ Look at testosterone levels in chess matches and found the same results
▪ Found the same in fans of teams
o juie ad roid rage
▪ Have people take steroids for 6 weeks: half get testosterone half get placebo
▪ 6 weeks off
▪ 6 weeks on but sapped if ou did’t first tie ou’d get it seod roud
▪ No increase in aggression except for in a significant minority
▪ Responders: those who take testosterone respond to having roid rage but the vast
ajorit do’t
o Other tasks
▪ Math reasoning, motor skills
#2: sex differences in behaviors are strongly influences by gonadal hormones
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Document Summary
Example 4: testosterone: stimulate growth and maintenance of male reproductive systems, stimulate 2 sex characteristics, hair growth, low voice, muscle mass, numerous effects on mood and behavior. #2: sex differences in behaviors are strongly influences by gonadal hormones. We"re (cid:271)uilt differe(cid:374)tl(cid:455: early investment is necessarily female, males have 1. Males and females are vulnerable in different ways (cid:862)i ha(cid:448)e (cid:271)ee(cid:374) (cid:374)oti(cid:272)i(cid:374)g (cid:455)ou arou(cid:374)d (cid:272)a(cid:373)pus. Go out with me tonight: males and females both said yes 50% Come over to my apartment tonight: males said yes 69% and females said yes 6% Have sex with me tonight: males said yes 75% and females said yes 0% #1: early nurturing of the child/embryo is necessarily female dominated (especially in mammals) Put male and female fruit flies into test tube and saw if the addition of males affected how many offspring they produced. More females for 1 male more offspring he produced. More males for 1 females no difference.
