Posted on 06/21/2012 11:42:30 AM PDT by Olog-hai
The origin of sexual reproduction was one of the most important events in the history of life—and it would not have been possible without granite. The igneous rock began forming in vast quantities around 2 billion years ago, bringing to the surface the metals that fuel complex life.
Life relies on a number of heavy metals to form proteins. Zinc, molybdenum and copper are particularly important for the eukaryotes—a group that includes animals, plants and fungi, all of which may reproduce sexually.
These complex organisms probably did not become widespread until the oceans became rich in the metals about 800 million years ago, but last year fossil evidence emerged showing that eukaryotes were living in freshwater lakes on land at least 1 billion years ago. So where did they get their heavy metal fix?
John Parnell at the University of Aberdeen, UK, and colleagues studied the rock record and say that an important event was the formation of an ancient supercontinent called Nuna, or Columbia, about 1.9 billion years ago, during the Palaeoproterozoic. …
When Nuna formed, large bodies of magma were injected into the continental crust where they cooled to form granite. This igneous rock is rich in metals including zinc, molybdenum and copper. Over time, natural erosion brought the granite to the surface where it, too, eroded, releasing the metals into the soil and water. Sedimentary records show that they were present in near-surface reservoirs and shallow bodies of water by 1 to 1.5 billion years ago, says Parnell.
"These metals were used by early cells to develop enzymes that enabled them to carry out a greater diversity of functions and begin to sexually reproduce," says Parnell. "They gave early life the added dimension of natural selection and variability." …
(Excerpt) Read more at newscientist.com ...
“One would like to believe in the freedom of music,
but glittering prizes and endless compromises
shatter the illusion of integrity”
I knew Motorhead had something to do with it!
I believe it was the great 20th century philosopher Brett Michaels who said...
“Down the basement,
Lock the cellar door,
And baby,
Talk dirty to me.”
It...just...brings a tear to my eye...sniff...
So profound.
Darwinians are coming up everywhere.
Unanswered is the question of “How did it come to pass that a population of organisms generated dual mutations simultaneous in time and space to produce a ‘male’ component and a ‘female’ component, which attached to each other and produced a new ‘male’ organism and the same thing happened twice and somehow produced a new ‘female’ organism, which then ended up in the same place and time to start reproducing sexually?”
The scientists: Always answering questions there are no answers for.
Making up an answer if one isn’t availbale.
Anyone who has a Motley Crue cassettes already knew that.
“She goes down....”
Evolutionary theory holds that there was a *long* history of progression, in many stages:
* From completely asexual reproduction, to partial exchange of genetic material;
* From completely asexual reproduction, to organisms that can reproduce both asexually and sexually (as exemplified in *many* organisms that still exist, from amoebas to aphids);
* From partially asexual/partially sexual, to completely sexual reproduction;
* From sexual reproduction with no dedicated sexes (which is still used by the majority of plants, and many "lower" animal forms), to sexual reproduction where individuals can become *either* male or female, to sexual reproduction with dedicated sexes (male and female).
* To all the many different ways that sexes are determined (e.g. determined by what they are fed during early development ... like bees and wasps; or individuals that can become male or female depending on mating opportunities ... like many types of molluscs, like slugs; or where males are haploid and females are diploid ... like ants; to male and female determined by temperature during gestation ... as in many types of reptiles; to males and females determined by X or Y chromosome ... which is the system used by us mammals).
* Finally, the transition from sexual reproduction with different sexes that are almost identical, to where the different sexes are significantly different ... like us humans, but even moreso in other mammals such as pinnipeds (seals and sea lions) or ungulates (deer, cows, goats, etc.).
It would take a *lot* more explanation to describe each of these stages ... and a *lot* more examples where all of these different transitions can still be seen in effect in modern organisms.
ping
Well, I do remember listening to my Aerosmith tape the night of my first time, so this study may be legit.
If an organism was reproducing asexually, what’s the theory/reasoning behind why they’d develop different sexual organs to reproduce sexually?
While we’re in the ballpark. . .What are some of the best examples of creatures who are presently in the middle of transitioning between species?
“large bodies of magma were injected into the continental crust”
Stop it, you’re turning me on!
Where is Laz when you need him?
“What are some of the best examples of creatures who are presently in the middle of transitioning between species?”
Liberals?
Bonobo chimps and Pan chimps are in the process of becoming separate species. It is exactly what one would expect if a river changed course a long time ago and ran through the middle of the chimp range. Chimps do not swim so the river was a reproductive barrier - and as is INEVITABLE - differences accumulated in separate populations - with the bonobo being smaller and much more sex crazed than its “cousins” across the river.
I think I am between a rock and a hard on this one.
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