Monogamy, Polygyny, Polyandry

Kelly D. Parungao PSYC 141 April 07, 2011

Mating Systems

 Monogamy - 1 male to 1 female  Polygyny - male mating with more than 1 female  Polyandry - female mating with more than 1 male

Monogamy

 When only a single parent is not enough to raise offspring, both parents are necessary.  Example of species in Monogamy: – Birds (Doves, Albatross) – Fish (Cichlid Fish) – Monkeys (Golden Lion Tamarins)

Albatross

 Will remain faithful to one another for life.  Baby birds cannot fly and due to this, both parents are needed.  One bird will protect the nest while the other retrieves food.  Essential for birds to be monogamous.

When Life Gets Easier

 In certain species, when life gets easier, one leaves. But who?

 Based on three factors: – 1. Internal or External Fertilization – 2. Who has more to gain?

– 3. Who is more depleted?

Polygyny

 Lions - exists as a pride – One male will be dominant in the pride, and be in charge for about 1 - 3 years – When males fight for dominance, if one is evicted from dominance position, the newly arrived male will kill the cubs of the previous males. – Males protect pride from hyenas.

Polyandry

 Sandpiper Birds (arctic) – Making eggs is easy due to the abundance of food.

– Males become protectors of eggs.



Polyandry

Acorn Woodpecker – Acorns need to be stored, and so these woodpeckers create deep holes in the trees and store them within. – Each hole is specific for each acorn, this is a hard job to collect and store, so a monogamous pair is not enough. – Correlation between # alive clutch to # of parents. Polyandry is necessary for this species for both male and female fitness to be optimal. BUT WHY?

“Monogamy unnatural for our sexy species” Christopher Ryan   Proposes that monogamy is not natural. “Fierce Egalitarianism” in hunter-gather societies.

 When we started to settle in communities, there was a bigger need to know who owned what.

Turning Towards Monogamy

 10th Commandment: “Thou shalt not covet thy neighbor’s house, thou shalt not covet thy neighbor’s wife, ….”  Not until we got into agriculture were we able to have wealth be kept in the family. Thus paternity became a concern.

Primate Species

 The two species that we are closest to are chimpanzees and bonobos.  Both sexually active with one another, in a non - monogamous society.

QuickTime™ and a decompressor are needed to see this picture.

Human Body

 Large male testicles.  Male sex organs outside of body to regulate a cool temperature.  Males reach orgasm before women.

 Women’s breasts, vocals and multiple orgasms.

Not Natural

 We choose to live a life of monogamy and that does not make us naturally monogamous.  A life choice.

 What’s your opinion? Are humans naturally monogamous?

Questions

 What are your thoughts on altruism and its relation to monogamy? Could it be that we care more for that one individual, causing us to only want to support and be with the other? And vice versa?

 What are your thoughts on arranged marriages? Is it a successful mating system?

Sources

 Evolutionary Analysis, 4th Edition Freeman  Monogamy unnatural for our sexy species http://www.cnn.com/2010/OPINION/07/ 27/ryan.promiscuity.normal/index.html