Study+Guid2[1] - Study Guide Exam 2 Anthropology 143 What...

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Unformatted text preview: Study Guide Exam 2 Anthropology 143 What is the best way to identify sex?- through eggs and sperm What are the costs and benefits of sexual reproduction?- costs: o transfer of diseases o maybe hard to find mates (take time) o recombination, mutation o only half of genes go into offspring- benefits o diversity of offspring o variation that natural selection can work on How do male and female gametes differ?- Male o Sperm o Small o Many- Female o Eggs o Large o Few What are the differences in parental investment between males and females? Anisogamy: sex cells of different sizes Isogamy: both sex cells are the same size Among mammals: Females produce eggs, which are larger and limited in number Males produce sperms, which are small and superabundant In primates: fetus develops fully inside mother, female produce milk, females primarily care the infants As a result, females invest more time and energy in young than males Differences in parental investment are at the root of sexual selection. Differences in investment produce different mating strategies Females are the limiting sex Males tend to be in excess Reproductive successes of females depend on how many offspring they can successfully care for (*Reproductive success (RS) = number of offspring produced who survive to reproduce themselves.) Reproductive successes of males depend on the number of infants they sire What is the Bateman Principal?- Fruit flies- Scored individual reproductive success Male RS Female RS 0 1 2 3 0 1 2 3 - # of Copulation partners- F tend to constrain M reproductive success than males constrain F Reproductive success- F produce fewer young, lower reproduction potential o # of mates not correlated w/ # of offspring- M more variance in reproductive potential o # of mates correlated w/ # of offspring- M compete over F- Selection acts more strongly on M- M have higher potential reproductive success- Males show greater variation in reproductive success What is Trivers Parental Investment Theory? Any behavior toward offspring that increases the chances of the offspring's survival at the cost of the parent's ability to invest in future offspring. Sex that invests least in offspring will compete for the sex that invests the most. Sex that invests most will be choosier of mates. Both males & females choose strategies to maximum their RS, thus females intensively care for each of a relatively small number of young, while males invest in siring a large number of offspring What is the difference between intra-sexual selection and inter-sexual selection?- Intra- sexual selection o Male- Male competition Shortage of resources FEMALES Contest competition in primates fighting Big, weapons, impressive looks, aggression, hormones, etc Scramble competition Efficiency Who can get there the fastest Sperm production, quality Readiness to mate o Female Female competition Most competition not sexually selected It is over food not resources, not mates...
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This note was uploaded on 04/11/2008 for the course ANTH 243 taught by Professor Stumpf during the Spring '07 term at University of Illinois at Urbana–Champaign.

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Study+Guid2[1] - Study Guide Exam 2 Anthropology 143 What...

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