Recording-2025-02-26T23:24:41.896Z

Phenotype and Reproductive Strategies

• Influence of Maternal Longevity

  • Maternal age significantly impacts offspring number, accounting for 50-70% of variance.

  • Importance of survival and longevity in maternal reproductive success.

Class Announcements

• Campus Quiz Update

  • Quiz number three results: average score around 85-86%.

  • Majority of students affected by one particular question regarding resource extraction times for human foragers vs. chimpanzees.

• Study Materials

  • A comprehensive study guide has been distributed for final exam preparation.

  • Jeopardy options will be provided for interactive review.

• Assignment Deadlines

  • Brighten Summit number three due next Wednesday.

  • Office hours available for additional support.

Infanticide as a Reproductive Strategy

• Behavioral Context

  • Infanticide is seen in various species, often as a strategy to enhance male reproductive fitness.

  • Males may kill infants to make mothers sexually receptive again, facilitating their potential mating.

• The Evolutionary Perspective

  • Research aimed to differentiate between infants’ paternity, whether they are from newcomers or resident males.

  • Key finding: New males more frequently target non-paternal infants, rarely killing those from females they previously mated with.

• Female Counterstrategies

  • Females may mate with multiple males to create confusion regarding paternity, decreasing risks of infanticide.

  • Evidence of sexual swellings during ovulation aids in this reproductive strategy.

Mating Systems in Humans

• Discussion of Early Hominins vs. Modern Humans

  • Common mating systems include pair bonding and polygamy, with variations depending on resources and social structures.

• Cultural Contexts

  • Polygamy common in certain regions (Western and Central Africa). In contrast, illegal in the U.S.

  • Economic stratification leads women to favor polygamous relationships in resource-rich societies.

Historical and Cultural Insights into Polygamy

• Historical Perspective

  • Polygyny noted in hunter-gatherer societies, with varying degrees of multiple partnerships.

  • Research indicates social rather than economic factors impact partnership structures in certain populations.

• Factors Influencing Polygamous Relationships

  • Importance of social capital in relationships observed in the Biaka population.

  • Pair bonded relationships average around 7 years, with high rates of remarriage post-divorce.

Evolutionary Psychology and Mate Preferences

• Predictions on Male and Female Preferences

  • Females typically prefer males with resources for child-rearing; males prefer young, healthy females.

  • Jealousy observed as a cross-cultural phenomenon; linked to mate guarding to retain resource investment.

• Cross-Cultural Preferences in Infidelity Types

  • Studies show men generally perceive sexual infidelity as more problematic than emotional infidelity, where women's preferences can vary significantly.

Himba Population Case Study

• Meeting Systems Among the Himba

  • Complex mating strategies present; include concurrent relationships and arranged marriages with a focus on genetic distance.

• Study of Parentage Among the Himba

  • Genetic studies indicate a high rate of non-paternity (48% children from boyfriends).

  • Investigations into first cousin marriages indicate avoidance of inbreeding despite cultural preferences.

• Inbreeding Avoidance Mechanisms

  • Psychological (Western Mark effect) and biological mechanisms could explain avoidance of sexual relationships among close kin.

  • Research finds no first cousins among sampled children, despite cultural practices suggesting otherwise.

  • Evidence of reduced fertility linked to higher rates of inbreeding; effects on surviving children noted.