tagged w/ Sexual Reproduction
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women's access to birth control has made remarkable progress in the 20th century,
although misinformation is still circulating.women's access to birth control has made remarkable progress in the 20th century,... more
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Sexual intercourse is poorly designed to give pleasure to both parties. Jeremy Laurance goes back to physiological basics.
Could explain why I am single then.
*cries*
Sexual intercourse is poorly designed to give pleasure to both parties. Jeremy... more
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JJ3000
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added this
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4 years ago
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"Asexual creatures do not even need to find a partner. While that might not sound like much fun, it certainly is efficient, working out to twice the reproductive capacity for a given number of organisms. So why did pond scum eventually evolve to procreate as we know and love it?
It might have all been a reaction to parasites, one theory holds.
See, the bad thing about reproduction sans sex is you make clones, and clones, and more clones. Every organism has the same DNA, other than mutations that occur over time. If a parasite figures out how to exploit a vulnerability, the entire species can be doomed.
But with good ol' sex comes unique combinations of DNA and genetically unique individuals. A parasite may kill many, but it's likely that some organisms won't be vulnerable and the species will live on.
All this has been modeled before. But the true test for any theory is what actually happens in nature.
So for 10 years, scientists studied Potamopyrgus antipodarum, a New Zealand freshwater snail that comes in a sexual and an asexual version. They counted the snails and the number of parasite infections for each variety.
Clones that were plentiful at the beginning of the study became more susceptible to parasites over time. As parasite infections increased, the once plentiful clones dwindled dramatically in number, the scientists write in the July issue of the journal American Naturalist. Some clonal types disappeared entirely.
Meanwhile, sexual snail populations remained more stable over time. This, the authors say, is exactly the pattern predicted by the parasite hypothesis.
"The rise and fall of these female-only lineages was surprisingly fast and consistent with the prediction of the parasite hypothesis for sex," said study team member Jukka Jokela of the Swiss Federal Institute of Aquatic Science and Technology. "These results suggest that sexual reproduction provides an evolutionary advantage in parasite rich environments.""Asexual creatures do not even need to find a partner. While that might not sound... more
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Mexico City is giving out free Viagra and other impotence drugs to men 70 and older.
Mayor Marcelo Ebrard says the city is implementing the plan because sexuality "has a lot to do with quality of life and our happiness."
City Health Secretary Armando Ahued says the government will start handing out doses of one or two Viagra, Levitra or Cialis pills on Dec. 1.
I guess it's baby-making time in Mexico!Mexico City is giving out free Viagra and other impotence drugs to men 70 and older.... more
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Moopak
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added this
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4 years ago
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A group of Canadian and European researchers have unlocked the mystery of a gene with the potential to both regulate and block ovulation. The new study — a collaboration between the Universite de Montreal in Canada and the Institut de genetique et biologie moleculaire et cellulaire of the Universite de Louis Pasteur, Strasbourg, France — is published in the latest issue of the journal Genes & Development.
"Our findings demonstrate that the Lrh1 gene is essential in regulating ovulation," said Bruce D. Murphy, director the Animal Research Centre at the Faculty of Veterinary Medicine and an adjunct professor of and obstetrics and gynaecology at the Faculty of Medicine of the Universite de Montreal. "Until this point, the role of Lrh1 in female fertility was unclear, but we have found the gene regulates multiple mechanisms of ovulation and may affect fertilization."
To reach their conclusions, the research team developed a new type of genetically modified mouse whose Lrh1 gene was selectively blocked in the ovary. They found that deletion of the Lrh1 gene effectively stopped ovulation. "This discovery means we can envision new contraceptives that selectively stop ovulation," said Dr. Murphy. "If created, these new contraceptives would be more effective and produce less side-effects than current steroid-based forms of birth control."
What’s more, the findings could lead to the development of pharmaceuticals that activate the Lrh1 gene, which may prove critical in giving infertile couples hope in producing children. "This is an important development, since 15 percent of couples are infertile," said Dr. Murphy. "The widespread role of this gene in the ovary indicates that it may be targeted to stimulate ovulation and, eventually, conception."
http://www.umontreal.ca/english/index.htmA group of Canadian and European researchers have unlocked the mystery of a gene with... more
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Leading scientist says that it could be the vaccines that cause autism.
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These are my favorite kind of birds.
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It's the hormones in the meat.
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Eating breakfast produces more males.
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Variety is the spice of life!
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Gina Conde is a health worker with a women's organisation and runs a clinic in the community where she lives. This is the story about her work to help other women understand their sexual and reproductive rights.Gina Conde is a health worker with a women's organisation and runs a clinic in... more
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If a woman wants an abortion, she will get an abortion, even if it's against the law.
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"Swim" is an abstract interpretation of conception and, more specifically, artificial insemination, produced entirely by graphic design. In a time where all is to be controlled, the elementary force of our very existence brings an undeniable fusion for a magic moment. This short film is simply about the power that brings us all to life."Swim" is an abstract interpretation of conception and, more specifically,... more
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The Modern World takes on the secular conspiracy concerning "sexual reproduction."The Modern World takes on the secular conspiracy concerning "sexual... more
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