Mystery of the male ostrich's erection solved

[웃 910]

This is in P&R because it mentions evolution...

Mystery of the male ostrich's erection solved

Getting an erection is no problem for male ostriches – but maintaining it for more than a few seconds is a different matter. The birds may have inherited their underpowered genitalia from their dinosaur ancestors.

The ####### is a vital piece of equipment for many vertebrates. Most male reptiles and mammals have them, and two of the most ancient groups of birds have them too, suggesting that dinosaurs, from which birds have descended, also possessed the male member. The majority of male birds don't have one, though: the reason why is something of a mystery.

The ostrich belongs to one of those two ancient, #######-bearing bird groups. It is a palaeognath, a group that also includes emus, kiwis and the near-flightless tinamous. The other endowed group is the Galloanserae, commonly known as fowl, which includes chickens, pheasants and ducks.

Many of these birds' penises are well understood, but the penises of ostriches and their relatives remained a mystery. So Richard Prum of Yale University and Patricia Brennan, now at the University of Massachusetts Amherst, obtained a dead ostrich and three emus to find out more.

Fast action

In both species they found spongy organs called paralymphatic bodies at the base of the #######. That tells us that the birds' penises fill up with lymphatic fluid to make an erection, like all other bird penises studied – and unlike reptiles and mammals, which use blood for the job.

That is bizarre, Brennan says, because the body keeps lymphatic fluid under lower pressure than blood. As a result, birds can't maintain an erection. "Copulation is very brief compared with mammals and reptiles," Brennan says. "It's a matter of a few seconds."

Brennan says she doesn't know why such an inefficient system would evolve, especially as it must have evolved from the more evolutionarily ancient blood-based system. However, all birds with penises produce erections this way, so the condition must already have existed in the last common ancestor of modern birds.

That last common ancestor was alive in the early Cretaceous, at least 130 million years ago. It is not clear now much further back down the bird evolutionary tree these inefficient penises might be found, but it is at least possible that the trait first appeared in the dinosaurs from which birds evolved.

Gregory Erickson of Florida State University in Tallahassee says it makes sense that dinosaurs had penises, but so far the fossil record has remained silent on the matter. It would take a dinosaur fossil with exceptional soft tissue presentation to establish whether dinosaur sex was as brief as the birds' or as leisurely as mammal and reptile couplings.

A dinosaur ####### would be far from the oldest in the fossil record, though: that crown is currently held by a tiny crustacean found in rocks 425 million years old.

http://www.newscient...ion-solved.html

Edited December 14, 2011 by Lord Infamous

[SMR 368]

This is in P&R because it mentions evolution...

Mystery of the male ostrich's erection solved

Getting an erection is no problem for male ostriches – but maintaining it for more than a few seconds is a different matter. The birds may have inherited their underpowered genitalia from their dinosaur ancestors.

The ####### is a vital piece of equipment for many vertebrates. Most male reptiles and mammals have them, and two of the most ancient groups of birds have them too, suggesting that dinosaurs, from which birds have descended, also possessed the male member. The majority of male birds don't have one, though: the reason why is something of a mystery.

The ostrich belongs to one of those two ancient, #######-bearing bird groups. It is a palaeognath, a group that also includes emus, kiwis and the near-flightless tinamous. The other endowed group is the Galloanserae, commonly known as fowl, which includes chickens, pheasants and ducks.

Many of these birds' penises are well understood, but the penises of ostriches and their relatives remained a mystery. So Richard Prum of Yale University and Patricia Brennan, now at the University of Massachusetts Amherst, obtained a dead ostrich and three emus to find out more.

Fast action

In both species they found spongy organs called paralymphatic bodies at the base of the #######. That tells us that the birds' penises fill up with lymphatic fluid to make an erection, like all other bird penises studied – and unlike reptiles and mammals, which use blood for the job.

That is bizarre, Brennan says, because the body keeps lymphatic fluid under lower pressure than blood. As a result, birds can't maintain an erection. "Copulation is very brief compared with mammals and reptiles," Brennan says. "It's a matter of a few seconds."

Brennan says she doesn't know why such an inefficient system would evolve, especially as it must have evolved from the more evolutionarily ancient blood-based system. However, all birds with penises produce erections this way, so the condition must already have existed in the last common ancestor of modern birds.

That last common ancestor was alive in the early Cretaceous, at least 130 million years ago. It is not clear now much further back down the bird evolutionary tree these inefficient penises might be found, but it is at least possible that the trait first appeared in the dinosaurs from which birds evolved.

Gregory Erickson of Florida State University in Tallahassee says it makes sense that dinosaurs had penises, but so far the fossil record has remained silent on the matter. It would take a dinosaur fossil with exceptional soft tissue presentation to establish whether dinosaur sex was as brief as the birds' or as leisurely as mammal and reptile couplings.

A dinosaur ####### would be far from the oldest in the fossil record, though: that crown is currently held by a tiny crustacean found in rocks 425 million years old.

http://www.newscient...ion-solved.html

Yet another example of scientists assuming evolution and then trying to figure out how the evidence supports it instead of looking at the evidence and trying to come up with the most likely theory to explain it.

[elmcitymaven 9,712]

Yet another example of scientists assuming evolution and then trying to figure out how the evidence supports it instead of looking at the evidence and trying to come up with the most likely theory to explain it.

What IS the most likely theory to explain it, then, if not evolution?

[Nina~ 431]

What IS the most likely theory to explain it, then, if not evolution?

The ostrich hasn't met a FSU woman

Edited December 14, 2011 by Nina~

[Mr. Big Dog 10,747]

The ostrich hasn't met a FSU woman

[Ban Hammer 13,760]

The ostrich hasn't met a FSU woman

[Dakine10 5,452]

The ostrich hasn't met a FSU woman

[kytwell 179]

If they were native to the USA, they could get on Medicare and get a ####### pump.

[Bad_Daddy 2,209]

The ostrich hasn't met a FSU woman

You took the words right out of my mouth.

If they were native to the USA, they could get on Medicare and get a ####### pump.

[Darnell 8,479]

Sorry, this isn't 'solved' until Amby has the final word.

One of yas go wake her up, get her to come here and 'make the final word'.

Soonish?

[Misha & Ira 113]

The ostrich hasn't met a FSU woman

Aint that the truth.

[Bad_Daddy 2,209]

Aint that the truth.

Iv'e often wondered if RUB chicks are trained in the art of pleasing a man or if it comes to them naturally. It's like they were born for it.

[Misha & Ira 113]

Like Sparrow class?

Edited December 14, 2011 by Misha & Ira

[kytwell 179]

Iv'e often wondered if RUB chicks are trained in the art of pleasing a man or if it comes to them naturally. It's like they were born for it.

There's a reason Greek and freak rhymes. I can't knock a RUB though, because I haven't tried one out.

[Bad_Daddy 2,209]

There's a reason Greek and freak rhymes. I can't knock a RUB though, because I haven't tried one out.