November-13-12 10:35 AM
Females pay attention to:
• Resource -holding potential
• Physical, athletic ability
• Kindness to children
Males pay attention:
• Cues of youth and fertility
• Waist to hip ratio (smaller hips)
Men might misdirect their paternity to offspring of another male
• Why does it happen?
○ Sex places different selection pressures on males than females;high investing sex
is a limiting factor for low investing sex
• Which sex competes,which chooses?
○ Males, females
• Can it operate on both sexes at the same time?
○ Yes, both can invest heavily
Selection is fundamentally competitive
• Fighting for mates
Both group living and cooperationare common
Types of social interaction
Actor benefits Actor is harmed
Recipient benefits Cooperation Altruism
Recipient is harmed Selfishness Spite
• Altruism is "a special difficulty, which at first appeared to me insuperable, and actually
fatal to my whole theory"
• Altruism reduces one's fitness for the increase of another's fitness
• Parents protecting offspring from a threat
• Some birds help their parents take care of other offspring (siblings)
• How can traits reducing fitness (offspring production) be selectivelyfavoured
○ Sacrificing individual fitness for the good of the group?
More to "fitness than simply producing direct descendants
• Personal reproduction --> direct fitness
• Additional reproduction by relatives do to your 'altruism' --> indirect fitness
• Direct + indirect fitness = inclusive fitness
• Kin selectionfavours traits that increase indirec