A Sketch of the Battlefield
Emily Berry and Morghen Philippi
Definition of Sex
● What is the definition of sex?
Definition of Sex
Merriam-Webster: the sum of the structural, functional,
and behavioral characteristics of organisms that are
involved in reproduction marked by the union of gametes
and that distinguish males and females
Bateman’s Principle
Natural selection favors males who eagerly
and indiscriminately pursue mates and choosy
females
● Polygyny: mating system in which males mate with
multiple females
● What support is there for Bateman’s Principle? Why
does it “make sense”? What would you say to someone
who teaches you the Bateman’s Principle?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096780/
Polyandry
Mating system in which females mate with
multiple males
● Why would polyandry evolve?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3576576/
Types of Polyandry
●
Convenience polyandry: Instead of expending energy to resist fighting unwanted matings, the females just
lay down and take it.
●
Fraternal polyandry: Male brothers mate with one female.
●
Genetic-benefit polyandry: In female arthropods that can store sperm, the female will mate with multiple
males in order to have a diverse sperm pool, and thus more genetic diversity, to fertilise her eggs with.
●
Mate-defence polyandry: As in the phalarope, where the female guards her multiple male mates.
●
Maternal-benefit polyandry: In which females mate with multiple males due to benefits given by sexuallyactive males, usually nutrition or protection.
●
Serial (sequential) polyandry: In which females form monogamous pairs with multiple males in succession.
Sick of Sex in India
● Mate for 10 weeks
Spooked in Gabon
● Spiky penis
●
http://shar.es/1mdWtx
Perplexed in Cloverhill
● Males die after sex
Time for a Game!
Complete the matches on your worksheet!
Matching Game!
A.
B.
D.
C.
H.
E.
F.
G.
So What?
● Why does sexual conflict exist? Shouldn’t males and
females want to cooperate?
● How does sexual conflict relate to the Red Queen
Hypothesis?
● What factors might promote the evolution of the
following mating systems:
o polyandry
o polygygy
o monogamy
Exploration
Develop a research question regarding sexual
conflict and polyandry.
● You have unlimited funds and resources
Sources For Worksheet
● http://www.bbc.com/earth/bespoke/story
/20140908-twisted-world-of-sexualorgans/index.html
● Dr. Tatiana’s Sex Advice to All Creation