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Complete program description for educators
  Series Overview |  Show 1 |  Show 2 |  Show 3 |  Show 4 |  Show 5 |  Show 6 |  Show 7
Show 5: Why Sex?

57 minutes, 7 DVD chapters

 
   
  Chapter 1. Prologue (2:40)  
 

Introduction to the show's theme: sex and genes, driving behavior and driving evolution

  • All living beings are programmed to transmit their genes to the next generation
  • From an evolutionary perspective, sex is more important than life

 
   
  Chapter 2. Lesbian Lizards (5:04)  
 

Asexual reproduction and questioning the importance of males

  • A female-only lizard species gives birth without having had sex; each egg has a complete set of her mother's genes
  • If a female-only species can thrive, are males necessary?
  • The biological imperative to pass on genes

 
   
  Chapter 3. The Advantage of Sex (9:46)  
 

Exploring the evolutionary advantages to sexual reproduction

  • Studying asexual and sexual reproduction in Sonoran minnows to demonstrate the value of males
  • The Red Queen theory: when a species stops evolving, it is doomed
  • The evolutionary advantages of genetic variability among offspring
  • Speculating on the origins of sex
  • Descriptions of sperm and eggs: quantity versus quality
  • At a deep biological level, males and females want different things

 
   
  Chapter 4. The Peacock's Tail (8:28)  
 

Male ornamentation and the theory of sexual selection

  • Darwin's theory of natural selection explained traits that improved species' survival, but not extravagances like the peacock's tail
  • Why are ornaments typically seen on males?
  • Ornaments as an indication of good genes
  • Male competition and female choice, as seen in peacock mate selection
  • In some species, females choose good behavioral traits or good genes

 
   
  Chapter 5. Songbirds and Monogamy (5:36)  
 

Shared parenting and its evolutionary implications

  • Monogamy as a social solution to a biological dilemma
  • Female songbirds cheating on mates to give offspring better genes
  • Jacana birds and the reversal of male-female roles
  • Gender roles determined by who competes for mates and who cares for young

 
   
  Chapter 6. Chimpanzees and Bonobos (8:13)  
 

Social differences between two closely related species

  • Chimpanzee society is patriarchal and violent
  • Bonobo society is peaceful, due to female solidarity
  • Exploring how a change in feeding ecology influenced chimpanzee and bonobo differences
  • Implications for early humans, and humans today

 
   
  Chapter 7. Sex and Human Behavior (16:44)  
 

Exploring how modern human behavior springs from our evolutionary past

  • Evolutionary psychologists' provocative theories about humans and our drive to reproduce
  • Research into human scent and genetic compatibility
  • Mate selection and the evolutionary roots of attractiveness
  • Did brains evolve, in part, to attract mates?
  • Humans have gone beyond the biological urge, and will raise children that do not share our genes

 
   
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