News tagged with sex
Adam's rib, revisited: Evolutionary divergence of mammalian sex chromosomes
(Phys.org) -- Males and females... Mars and Venus... XY and XX chromosomes -- all are common memes. At the same time, the evolution of therian (placental and marsupial) sex chromosomes is less widely understood. ...
Apr 18, 2012 |
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Sexual reproduction works thanks to ever-evolving host, parasite relationships: study
(PhysOrg.com) -- It seems we may have parasites to thank for the existence of sex as we know it. Indiana University biologists have found that, although sexual reproduction between two individuals is costly ...
Jul 07, 2011 |
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A post-coital switch: Mapping the changing behaviors in the female fruit fly's mind
If men are from Mars and women are from Venus, then it shouldn't be surprising that their neural circuits differ. In research published today in the journal Current Biology, researchers have used dramatic change ...
May 31, 2012 |
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Sex: it's a good thing, evolutionarily speaking
(Phys.org) -- Sure, sex may be fun, but it’s a lot of work, and the payoff is by no means certain. Scientists have speculated for a long time on why all living things don’t simply make like amoebas ...
May 30, 2012 |
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Men can rest easy -- sex chromosomes are here to stay
Fears that sex-linked chromosomes, such as the male Y chromosome, are doomed to extinction have been refuted in a new genetic study which examines the sex chromosomes of chickens.
May 08, 2012 |
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Early spring means more bat girls
There must be something in the warm breeze. A study on bats by a University of Calgary researcher suggests that bats produce twice as many female babies as male ones in years when spring comes early.
May 05, 2012 |
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Biologists turn back the clock to understand evolution of sex differences
Sex differences account for some of the most of the spectacular traits in nature: the wild colours of male guppies, the plumage of peacocks, tusks on walruses and antlers on moose. Sexual conflict – the ...
May 03, 2012 |
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Promiscuous queen bees maintain genetic diversity
By mating with nearly 100 males, queen bees on isolated islands avoid inbreeding and keep colonies healthy.
Apr 16, 2012 |
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Do parasites evolve to exploit gender differences in hosts?
Some disease-causing parasites are known to favor one sex over the other in their host species, and such differences between the sexes have generally been attributed to differences in immune responses or behavior. But in ...
Feb 28, 2012 |
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Sex-specific behaviors traced to hormone-controlled genes in the brain
Hormones shape our bodies, make us fertile, excite our most basic urges, and as scientists have known for years, they govern the behaviors that separate men from women. But how?
Feb 02, 2012 |
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Male spiders of one species lose their genitals after sex to increase sperm count in females
(PhysOrg.com) -- Researchers have known for some time that the male sex organ, called a palp, in orb-web spiders is often broken off during copulation with females; what hasn’t been so clear is why. ...
Feb 02, 2012 |
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PNAS-published poll finds some Christians find their own political beliefs conflict with Jesus' teachings
(PhysOrg.com) -- A new online poll conducted by a team of three researchers from Stanford University has found that of those who identified themselves as Christians and who also identified themselves as either politically ...
Other Sciences / Social Sciences
Jan 31, 2012 |
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High-energy lifestyles led to evolution of the sexes
Scientists are a step closer to explaining one of the most enduring mysteries of modern biology; why are there males and females?
Dec 19, 2011 |
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Mitochondria and the great gender divide
(Medical Xpress) -- Why are there two sexes? It’s a question that has long perplexed generations of scientists, but researchers from UCL have come up with a radical new answer: mitochondria.
Dec 09, 2011 |
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Worms can evolve to survive intersex populations
(PhysOrg.com) -- Sexually reproducing species need at least two sexes in order to produce offspring, but there are many ways that nature produces different sexes. Many animals (including humans and other mammals) ...
Dec 06, 2011 |
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Sex
In biology, sex is a process of combining and mixing genetic traits, often resulting in the specialization of organisms into male and female types (or sexes). Sexual reproduction involves combining specialized cells (gametes) to form offspring that inherit traits from both parents. Gametes can be identical in form and function (known as isogametes), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist: male gametes are small, motile, and optimized to transport their genetic information over a distance, while female gametes are large, non-motile and contain the nutrients necessary for the early development of the young organism.
An organism's sex is defined by the gametes it produces: males produce male gametes (spermatozoa, or sperm) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic. Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience.
For more information about Sex, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
