Biologist Robert Vrijenhoek has been studying the Mexican Poeciliid fish for more than 30 years. Some species of Poeciliopsis reproduce sexually while others reproduce asexually. Vrijenhoek found that the genetic diversity produced by sexual reproduction allowed the sexual fish to survive a parasite more successfully than the asexual fish. Invoking the Red Queen hypothesis, Vrijenhoek suggests the sexual populations are able to keep up or adapt to new selective challenges, while the asexual populations, essentially clonal, are not. From Evolution: "Why Sex?" Also featured: Meredith Small.

Many say that our culture is obsessed with sex, and uses sexual references to sell everything from fragrances to cars. And wouldn't life be dull without it? Yet from the viewpoint of evolutionary theory, sex isn't the most efficient way of reproducing. In fact, scientists have been asking for decades, why does sexual reproduction even exist?

If the goal of life is spreading one's genes far and wide, asexually reproducing organisms seem to have the edge. They do not have to invest time and energy finding a mate. Asexual individuals can pass on their genes twice as fast as those reproducing sexually, because they pass on all their genes -- and only their genes. When reproduction is sexual, half of the genes handed on to the next generation are those of the other parent. The offspring may lose some of the genetic traits that made each parent successful.

There are many hypotheses but, until recently, little hard evidence on the advantages of sex. They stem from the notion that the genetic variation created in sexual reproduction is worth the cost. And at least in some environments, that variation must give a competitive edge over asexual organisms that can spread their genes efficiently, but vary little from one generation to the next.

One explanation is the increasingly popular Red Queen hypothesis, referring to the huffy chess piece in Lewis Carroll's Through the Looking Glass. In Looking Glass Land, the Queen tells Alice, "It takes all the running you can do, to keep in the same place." According to the Red Queen hypothesis, sexual reproduction persists because it enables many species to rapidly evolve new genetic defenses against parasites that attempt to live off them.

Scientists from Rutgers University in New Jersey have tested this idea by observing different groups of small fish called topminnow in Mexico. Some populations of the topminnow reproduce sexually, while others reproduce asexually, so they provide the perfect opportunity to test these ideas. The topminnow is under constant attack by a parasite, a worm that causes something called black-spot disease.

The researchers found that identical populations ("clones") of the asexually reproducing topminnows harbored many more black-spot worms than did those producing sexually, a finding that fit the Red Queen hypothesis: The sexual topminnows could devise new defenses faster by recombination than the asexually producing clones.

Please Subscribe To The WhyEvolutionIsTrue Youtube Channel.

More Short Videos On Evolution:


You need to be a member of Atheist Nexus to add comments!

Join Atheist Nexus

Support Atheist Nexus

Donate Today



Help Nexus When You Buy From Amazon




Latest Activity

Freethinker31 commented on WayneO's blog post And the Evening and the Morning Were the Fourth Day
3 minutes ago
Kelvin Hilerio replied to satyam dangi's discussion Do we need to change the entire spectrum of human civilization ?
4 minutes ago
Freethinker31 replied to Christine's discussion What exactly is "sin" anyway??
13 minutes ago
Kelvin Hilerio posted a status
"About to play Tearaway later 2night!"
17 minutes ago
Christine posted a discussion
21 minutes ago
Freethinker31 replied to Joan Denoo's discussion My gravesite inscription
22 minutes ago
Will-I Am S. replied to scott martins's discussion IS EVERYBODY 100% POSITIVE THERE IS NO GOD?
25 minutes ago
Freethinker31 replied to Joan Denoo's discussion How Creationists in Texas Are Pressuring Schoolbook Publishers to Bring God into Biology
30 minutes ago
Malcolm Grant Hutton replied to Malcolm Grant Hutton's discussion Impossible Numbers in the Bible in the group Christian Biblical Errancy Debate
31 minutes ago
Freethinker31 liked Joan Denoo's discussion How Creationists in Texas Are Pressuring Schoolbook Publishers to Bring God into Biology
32 minutes ago
Joseph P replied to Joe's discussion The IRS Says It Will Finally Enforce the Rules Barring Pastors from Endorsing Candidates from the Pulpit in the group Atheist News
37 minutes ago
Kelvin Hilerio replied to Joan Denoo's discussion How Creationists in Texas Are Pressuring Schoolbook Publishers to Bring God into Biology
42 minutes ago

© 2014   Atheist Nexus. All rights reserved. Admin: Richard Haynes.

Badges  |  Report an Issue  |  Terms of Service