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.
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1
2
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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.
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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!!
You'll Be More Conspicuous to Predators
Male Superb Bird of Paradise
This takes ATP!!
Sex Increases Risk of Diseases
That Lead to:
Sickness
Infertility
Death
So, Why Sex?
b/c it gives us
BIG benefits
against
ANTIGENS!!!
!
WHAT???????? I don’t get it
--
QuickTime™ and a
decompressor
are needed to see this picture.
The Red 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!!
QuickTime™ and a
decompressor
are needed to see this picture.


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.



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.
Sex is the
best
strategy for
winning the
lottery…
keeping
your genes
afloat!!
Lucky in Love
Increasing Variety =
Greater Success
The
Difference
Between
Males
and
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
1,042
Children
Love is Like a Game of Chess
It's All About Strategy
Base Your Decisions on the
Environment in Which You Live
Monogamy...
My Heart Beats Only For You
Polygamy...
I Love You and You and You and You and
Monogamy
Less disease risk
Can guard your mate
Lower infanticide
Form social bonds
Less male competition
Polygamy
More diversity in offspring
Produce more offspring
Less commitment
How
Many
Offspring
Should
You
Have?
If You Decide to Have Few...
This takes ATP!!
You
Must
Provide
Parental
Care
If You Decide to Have Many...
You Won't Have to Provide Parental Care
But,
You'll
Probably
Be So
Exhausted
That You'll Die Soon Afterwards
Are You a Desperate Male?
Commit
Sexual
Suicide
It's Better
to Have
Loved
and
Lost
Then to
Have Never
Loved at All!
Or Allow Yourself to Be Exploited
And Persist as a Tiny
Blood-Sucking Parasite
Attached to the Female's Body
What
if a
Member
of the
Opposite
Sex
is Not
Available?
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
QuickTime™ and a
decompressor
are needed to see this picture.
And Now for the Finale
The
Greatest
Human
Drumroll Please
Mating
Behavior
of
All
Time
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=C06051C8BA2A5A
2C4196C3EDFEC0E7E6A55A1E4F32AD3138
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.jp
g/300px-Callorhinus_ursinus_and_harem.jpg
Slide #
Photographer
URL
21 alb
James Preston
http://www.flickr.com/photos/jamespreston/88920149/
21 lion
Brian Scott
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-nightfever/saturday-night-fever-1-1024.jpg
41
ucumari
http://www.flickr.com/photos/ucumari/427035041/