Major Insights into Evolution of Human Life.

Humans might not be walking the face of the Earth were it not for the ancient fusing of two prokaryotes — tiny life forms that do not have a cellular nucleus.

Very interesting discovery, or research, here, that sheds light on the link between single-celled organisms and the more complex creatures that followed.

Also explains how cyanobacteria transformed the non-oxygen rich atmosphere into one that could sustain life such as our own.

UCLA molecular biologist James A. Lake reports important new insights about prokaryotes and the evolution of life in the Aug. 20 advance online edition of the journal Nature. Endosymbiosis refers to a cell living within another cell. If the cells live together long enough, they will exchange genes; they merge but often keep their own cell membranes and sometimes their own genomes.

Lake has discovered the first exclusively prokaryote endosymbiosis. All other known endosymbioses have involved a eukaryote — a cell that contains a nucleus. Eukaryotes are found in all multicellular forms of life, including humans, animals and plants.

"This relationship resulted in a totally different type of life on Earth," said Lake, a UCLA distinguished professor of molecular, cell and developmental biology and of human genetics. "We thought eukaryotes always needed to be present to do it, but we were wrong."

In the Nature paper, Lake reports that two groups of prokaryotes — actinobacteria and clostridia — came together and produced "double-membrane" prokaryotes. "Higher life would not have happened without this event," Lake said. "These are very important organisms. At the time these two early prokaryotes were evolving, there was no oxygen in the Earth's atmosphere. Humans could not live. No oxygen-breathing organisms could live." The oxygen on the Earth is the result of a subgroup of these double-membrane prokaryotes, Lake said.

This subgroup, the cyanobacteria, used the sun's energy to produce oxygen through photosynthesis. They have been tremendously productive, pumping oxygen into the atmosphere; we could not breathe without them. In addition, the double-membrane prokaryotic fusion supplied the mitochondria that are present in every human cell, he said.

"This work is a major advance in our understanding of how a group of organisms came to be that learned to harness the sun and then effected the greatest environmental change the Earth has ever seen, in this case with beneficial results," said Carl Pilcher, director of the NASA Astrobiology Institute, headquartered at the NASA Ames Research Center in Moffett Field, Calif., which co-funded the study with the National Science Foundation.

Endosymbiosis allowed the cyanobacteria to harness the sun's energy, creating a livable climate for those organisms that followed: us.

More at the link:
machineslikeus.com...

it would be cool if humans could do photosysthisis.
cept weed all be GREEN

I know that in us we have genes that allow us to produce Vitamin C but they are off in primates for some reason. Since the human genome has been mapped, I wonder when we'll be able start fiddling with the on/off switches of these functions.

it would be cool if humans could do photosysthisis.
cept weed all be GREEN

I'm sure Captain Kirk would have no problem with that...

reply to post by Welfhard


I too await the point in time where we can simply do away with genetic diseases and the like by going to a clinic and getting the "tracers" switched off and on accordingly.
How science fiction could it get I wonder?

This month...I want blue eyes. Come spring though, I think green would be in season.


Is that a realistic possibility, I have no clue. It's fun to wonder about though.

reply to post by Spiritfilled


This is completely off-topic, but I watched a japanese animation recently which was set in a devastated future earth setting, where humans could combine with trees.

It was pretty cool - the plant part made them green and 'barky'.

And they had crazy wood strength.

cartoon, I know, but awesome? totally...

reply to post by makinho21


The next phase in our evolution will be as much technological as biological. First it will start with cybernetic implants. Later it will be genetic filtering (of deleterious genes). I suspect that eventually, we will turn ourselves into synthetic life.

We are lucky enough to be standing on the precipice of science fiction to fact, my friend, and the view looks good.

reply to post by Welfhard

Indeed - nice pic btw - with the exponential growth of computer technology, the imminent arrival of quantum computers, and our ever-increasing understanding of how we, ourselves, work, I think we'll see a huge change in our perceived existence in the next decade or so.

I think the supposed "singularity" date is 2028 is it not?

When the understanding of our brain is complete, and our computer technology is great enough to perform the tasks of a brain.

We will be able to map ourselves out onto computers, and live "forever" in a way.


Something like that....

reply to post by makinho21


I don't think there will be a singularity, I think our rate of advancement will reach a kind of terminal velocity whereby complicating factors will slow us down. But still aslong as we're moving forward!

[edit on 21-8-2009 by Welfhard]

"These are very important organisms. At the time these two early prokaryotes were evolving, there was no oxygen in the Earth's atmosphere. Humans could not live. No oxygen-breathing organisms could live." The oxygen on the Earth is the result of a subgroup of these double-membrane prokaryotes, Lake said. "

Rubbish.

Half of the worlds oxygen comes from the oceans...

The water there is made of one hydrogen atom and two oxygen atoms..... I'm sure the ocean would have released just as much oxygen then as it does now. maybe a bit more now, but it wouldnt have been that big a difference.

reply to post by Spiritfilled

Yes, I suppose we would be. Gene Wolfe anticipated your point in his novel, The Claw of the Conciliator. One of the characters in it is named the Green Man because he is, and he is because - yes - he gains energy through photosynthesis.

Energy is only one of the reasons why we feed, however; we must also ingest the matter of which our bodies are made, and which requires continual replacement. Being able to photosynthesize isn't going to absolve us from the need to eat.