The Biology of Love*

*Please note. This discussion in no way attempts to discuss love in a religious context. Rather it is merely an entertaining way to learn about the sometimes comical world of biological reproduction.

“If not for sex[ual reproduction], much of what is flamboyant and beautiful in nature would not exist.”

–Olivia Judson, Dr. Tatiana’s Sex Advice to All Creation

Why Sex?

A sexual organism has only 50% of the “fitness” of an asexual organism. In a game between sex and "asex," asex

always wins -- other things being equal. That's because asexual reproduction is

easier, and it's guaranteed to pass genes on to one's offspring.

1 2 3 41 2

A sexual organism has only 50% of the “fitness” of an asexual organism. asexuality is more common in

species that are little troubled by disease: boom-and-bust

microscopic creatures, arctic or high-altitude plants and insects.

1 2 3 41 2

So, I ask again…Why Sex?

You Have to Find and Woo a Mate

This takes ATP!!

You Have to Fight to Win Their Love

This takes ATP!!This takes ATP!!

You'll Be More Conspicuous to Predators

This takes ATP!!This takes ATP!!

Male Superb Bird of Paradise

Sex Increases Risk of Diseases

That Lead to: Sickness

InfertilityDeath

So, Why Sex?

b/c it gives us BIG

benefits against

ANTIGENS!!!!

WHAT???????? I don’t get it --WHAT???????? I don’t get it --

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The Red QueenRed Queen Hypothesis

The Red Queen's Hypothesis is an evolutionary hypothesis ~ 1983.

The term is taken from the Red Queen's race in Lewis Carroll's “Through the Looking-Glass”.

The Red Queen said: "It takes all the running you can do, to keep in the same place."

The Red Queen Principle can be stated thus:

"For an evolutionary system, continuing development is needed just in order to maintain its fitness relative to the systems it is co-evolving with.

When one changes… (prey) so does the other have to (predator)!

The hypothesis is intended to explain the advantage of sexual reproduction at the level of individuals.

By making every individual an experiment, when mixing mother's and father's genes, sexual reproduction may allow a species to evolve quickly-

…just to hold onto the ecological niche that it already has in the ecosystem.

First coined by Leigh Van Valen of the University of Chicago, it refers to Lewis Carroll's Through the Looking Glass, in which the Red Queen tells Alice, "It takes all the running you can do, to keep in the same place."

This never-ending evolutionary cycle describes many natural interactions between hosts and disease, or between predators and prey: As species that live at each other's expense coevolve, they are engaged in a constant evolutionary struggle for a survival advantage. They need "all the running they can do," because the landscape around them is constantly changing.

The Red Queen hypothesis for sex is simple: SEX IS NEEDED TO FIGHT DISEASE!!

Diseases specialize in breaking into cells, either to eat them, as fungi and bacteria do, or, like viruses, to subvert their genetic machinery for the purpose of making new viruses.

To do that they use protein molecules that bind to other molecules on cell surfaces. The arms races between parasites and their hosts are all about these binding proteins.

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The Red Queen hypothesis for sex is simple: SEX IS NEEDED TO FIGHT DISEASE!!

Parasites invent new keys; For if one lock is common in one generation, the key that fits it will spread like wildfire.

So you can be sure that it is the very lock not to have a few generations later.

The Red Queen hypothesis for sex is simple: SEX IS NEEDED TO FIGHT DISEASE!!

According to the Red Queen hypothesis, sexual reproduction persists because it enables host species to evolve new genetic defenses against parasites that attempt to live off them.

Lucky in Love

Sex is the best

strategy for

winning the

lottery… keeping

your genes afloat!!

Greater SuccessIncreasing Variety =

The Differenc

eBetweenMalesand

Females

Between 1725-1765,the Wife of Feodor Vassilyev had

69 Children

In Her 27 Pregnancies:she Gave Birth to *16 Pairs of Twins *7 Sets of Triplets *4 Sets of Quadruplets

1,042Children

Love is Like a Game of ChessIt's All About Strategy

Base Your Decisions on theEnvironment Environment in Which You Live

Make the

Choice

That Wil

l Lead t

o

the Grea

test Num

ber of S

uccessfu

l

Offsprin

g!

Monogamy...My Heart Beats Only For You

Polygamy...

I Love You and You and You and You and

Monogamy PolygamyLess disease risk More diversity in offspringCan guard your mate Produce more offspringLower infanticide Less commitmentForm social bondsLess male competition

HowMany

Offspring

ShouldYouHave?

If You Decide to Have Few...

YouMust

ProvideParental

Care

This takes ATP!!This takes ATP!!

If You Decide to Have Many...

You Won't Have to Provide Parental Care

That You'll Die Soon Afterwards

But,You'll

ProbablyBe So

Exhausted

Are You a Desperate Male?

CommitSexualSuicide

It's Better

to HaveLoved

andLost

Then toHave Never

Loved at All!

Or Allow Yourself to Be Exploited

And Persist as a TinyBlood-Sucking ParasiteAttached to the Female's

Body

Whatif a

Memberof the

OppositeSex

is NotAvailable?

Get a Sex Change!

But, What if You're Alone?

Shy?

Rejected?

Unable to find a mate?

All is Not Lost

Go Asexual

But, Remember You Lose the Benefits of Sex So Switch Back When Possible

Arguably the Most Exquisitely Evolved

Mating Behaviors Belong to Class Aves

Arguably the Most Exquisitely Evolved

Mating Behaviors Belong to Class Aves

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TheGreatest

HumanMating

Behaviorof

AllTime

And Now for the Finale

Drumroll Please

The End

Photo Credits

Slide # Photographer URL

3 Unknown http://www.scienceagogo.com/news/img/sperm_egg_1is.jpg

4 Michael Reeve http://upload.wikimedia.org/wikipedia/commons/f/fc/Evolsex-dia1a.png

5 Arthur Morris http://www.birdsasart.com/Royal-terns-courtship-feeding-DeSoto-FL-_H2D8575.jpg

6 Unknown http://cache.viewimages.com/xc/3290720.jpg?v=1&c=ViewImages&k=2&d=C06051C8BA2A5A2C4196C3EDFEC0E7E6A55A1E4F32AD3138

7 Billy Campbell http://l.yimg.com/img.tv.yahoo.com/tv/us/img/site/81/22/0000038122_20070301141540.jpg

8 Lampron http://www.health2know.com/images/herpes.jpg

9 Unknown http://www.scienceagogo.com/news/img/sperm_egg_1is.jpg

10 Unknown http://www.alice-in-wonderland.net/alicepic/disney-movie/alice-with-queen-of-hearts.jpg

11 John Tenniel http://www.proteusadvisors.com/uploaded_images/Red-Queen-733514.jpg

12 Unknown http://bp3.blogger.com/_92E8fZ0HCXg/Rx5CWQhSyxI/AAAAAAAABJQ/t-P_NSFEcyo/s1600-h/lottery+balls.jpg

13 Unknown http://cache.gizmodo.com/assets/resources/2007/05/dpuzzle_640.gif

14 Steven Rhoads http://www.flatrock.org.nz/topics/society_culture/assets/sex_differences.jpg

15 Can you identify? Found on Creative Commons Flickr Search

16 Unknown http://en.wikipedia.org/wiki/Image:Moulay_Ismail.jpg

17 PoppyW http://www.flickr.com/photos/poppyw/348928452/

18 Can you identify? Found on Creative Commons Flickr Search

19 WTL http://www.flickr.com/photos/wtlphotos/1045750850/

20 M. Boylen http://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Callorhinus_ursinus_and_harem.jpg/300px-Callorhinus_ursinus_and_harem.jpg

Slide # Photographer URL

21 alb

21 lion

James Preston

Brian Scott

http://www.flickr.com/photos/jamespreston/88920149/

http://www.flickr.com/photos/brianscott/283824665/

22 Can you identify? Found on Creative Commons Flickr Search

23 Martha de Jong-Lantink http://www.flickr.com/photos/marthaenpiet/2093911204/

24 Can you identify? Found on Creative Commons Flickr Search

25 Unknown http://www.bpa.gov/corporate/BPANews/Library/images/fish/Chinook_eggs.jpg

26 Anvi http://www.anvious.com/archive/photoblog/061026.jpg

27 Can you identify? Found on Creative Commons Flickr Search

28 TarynMarie http://www.flickr.com/photos/tarynmarie/233251372/

29 T.W. Pietsch http://rmbr.nus.edu.sg/news/images/20050129-photocorynus_spiniceps-male_female.jpg

30 Kawa0310 http://www.flickr.com/photos/the_road_ahead/130768000/

31 tlindenbaum http://www.flickr.com/photos/lindenbaum/360684002/

32 ucumari http://www.flickr.com/photos/ucumari/580865728/

33 Jill Greenberg http://photomediamagazineonline.com/wp-content/uploads/2006/10/JG-monkeysuitff.jpg

34 Arnar Valdimarsson http://www.flickr.com/photos/arnar/95116503/

35 Mike Kemp http://images.jupiterimages.com/common/detail/96/47/23494796.jpg

36 Unknown http://www.rivalryrecords.com/BAND_LOGOS/logo_GoItAlone_LP.jpg

37 Tim Knight http://homepage.mac.com/wildlifeweb/reptile/komodo_dragon/komodo_dragon_04tfk.jpg

38 Sailing Nomad http://www.flickr.com/photos/ryanwhisner/363966960/

40 Unknown http://www.moviewallpapers.net/images/wallpapers/1977/saturday-night-fever/saturday-night-fever-1-1024.jpg

41 ucumari http://www.flickr.com/photos/ucumari/427035041/