The ancestor of all life on Earth might have been a gigantic planetary super-organism
All life on Earth is related, which means we all must share a single common evolutionary ancestor. And now it appears that this ancestor might have been a single, planet-spanning organism that lived in a time that predates the development of survival of the fittest.
That’s the idea put forward by researchers at the University of Illinois, who believe the last universal common ancestor, or LUCA, was actually a single organism that lived about three billion years ago. This organism was unlike anything we’ve ever seen, and was basically an amorphous conglomeration of cells.
Instead of competing for resources and developing into separate lifeforms, cells spent hundreds of millions of years freely exchanging genetic material with each other, which allowed species to obtain the tools to survive without ever having to compete for anything. That’s maybe not an organism as we would comprehend it today, but that’s the closest term we have for this cooperative arrangement.
All that we know about LUCA is based on conjecture, and the most promising recent research has been in figuring out what proteins and other structures are shared across all three domains of life: the unicellular bacteria and archaea and the multi-celled eukaryotes, which are where all plants and animals evolved from. This isn’t a foolproof method — it’s possible that two extremely similar but not identical structures could evolve independently after LUCA split into the three domains — but it’s a good starting point.
Illinois researcher Gustavo Caetano-Anollés says about five to eleven percent of modern proteins could be traced back to LUCA. Based on the function of these particular proteins, it appears LUCA had the enzymes needed to break down nutrients and get energy from them, and it could also make proteins, but it probably didn’t have the tools necessary to make DNA. This fits with other research that suggests LUCA fed upon many different food sources, and that it had internal structures in its cells known as organelles.
The big difference between LUCA and everything that came after, of course, is DNA. Because LUCA didn’t have the tools to deal with DNA, it probably used RNA instead, and it likely had very little control over the proteins that it made. The research suggests the ability to precisely control protein manufacture only came long after LUCA split apart, which means that protein-making was probably always a big crapshoot.
That’s why LUCA had to be cooperative, with any cells that produced useful proteins able to pass them on throughout the world without competition. This was a weird variation on what we know as natural selections — helpful proteins could go from a single cell to global distribution, while harmful or useless proteins were quickly weeded out and discarded. The result was the equivalent of a planet-spanning organism.
So why did this paradise of cellular cooperation give way to the last three billion years of cutthroat competition? The simple answer is that some cells probably outgrew this arrangement, as they had finally developed all the structures needed to survive without help. We don’t know quite why that happened, but it appears to coincide with the sharp increase of oxygen in the atmosphere. Whatever the cause, cells began eking out their own independent existences, ending the reign of LUCA that had lasted hundreds of millions of years… while beginning a new order that is still going strong 2.9 billion years later.
The trailers for this series got me really interested in checking out the first few episodes, and maybe I’m being too picky but I’m feeling as though it’s trying to be Lost and Jurassic Park. (The most recent episode of South Park “Ass-burgers” also made a comment to that point, so I know I’m not alone in thinking that.)
The way it’s shot, and the way it’s edited, along with the way the characters are acting/being directed, screams Lost. But if you can forgive that, which I can, it’s a very well-made show and has a very interesting concept. I’m excited to see what they do with it.
Okay, some back story, Jim Shannon and his family live in the distant future where we’ve fucked up our environment so much that we’ve made the Earth practically uninhabitable. There is a program called Terra Nova where people are sent back in time to before we fucked things up. 85 million years before we fucked things up. So they’re with the dinosaurs; pretty cool concept.
So they have this new colony that’s meant to start the human race anew in a separate timeline (cause apparently it’s not “their” past, it’s an alternate reality’s past) which is also very cool!
The inhabitants of Terra Nova are all from different waves of pilgrims; the sixth wave of people broke off from the group and they’re causing problems for Terra Nova but that’s about all that we know about them.
Anyway, if you’re confused you should just go watch the episodes, we’re only 3 in so far. So long story short, main character Jim becomes the head of security of Terra Nova and learns the reason why his wife was chosen to be in the Terra Nova project … another scientist requested that she be chosen … and he’s her ex! …. 😮 wha??!?!?
*rolls eyes (a love triangle story-arc coming up? I don’t see that coming) 😉
Um, you owe your continued existence to the fact that this man has the hots for your wife … and if he was secure in his relationship with his wife he shouldn’t have to worry that she’ll hook up with Dr. Wallace.
I just thought he didn’t have to be such a dick about it.
Maybe it’s because he hasn’t seen his wife in years because he was in a prison and now he’s suspicious of anyone because now that he’s finally back with his wife, he’s feeling insecure … that could explain it. But still, a little trust goes a long way. And is infidelity really a reason to end a relationship? We’re homo-sapiens, our sole purpose here on this planet is to procreate and raise the next generation of homo-sapiens. Sex, as it turns out, is a lot of fun and telling someone, you’re only allowed to experience certain aspects of life with one person while you’re in a “relationship” is, I think, naive and disingenuous to the fact that we are homo-sapiens and therefore mammals and that we enjoy sex.
What is it about sex that makes people act so intensely about “ownership” of who gets to sleep with who? What is it about that act that causes jealousy? Could it be an evolutionary trait ingrained in our species to ensure that our genes are the ones that are passed down to “our” children and ensure that they are in fact “our” children and not the children of man down the street who your wife has secretly been sleeping with?
What is the meaning behind jealousy?
Via Science Codex
CHAMPAIGN, Ill. — Scientists call it LUCA, the Last Universal Common Ancestor, but they don’t know much about this great-grandparent of all living things. Many believe LUCA was little more than a crude assemblage of molecular parts, a chemical soup out of which evolution gradually constructed more complex forms. Some scientists still debate whether it was even a cell.
New evidence suggests that LUCA was a sophisticated organism after all, with a complex structure recognizable as a cell, researchers report.
The study builds on several years of research into a once-overlooked feature of microbial cells, a region with a high concentration of polyphosphate, a type of energy currency in cells. Researchers report that this polyphosphate storage site actually represents the first known universal organelle, a structure once thought to be absent from bacteria and their distantly related microbial cousins, the archaea. This organelle, the evidence indicates, is present in the three domains of life: bacteria, archaea and eukaryotes (plants, animals, fungi, algae and everything else).
The existence of an organelle in bacteria goes against the traditional definition of these organisms, said University of Illinois crop sciences professor Manfredo Seufferheld, who led the study.
“It was a dogma of microbiology that organelles weren’t present in bacteria,” he said. But in 2003 in a paper in the Journal of Biological Chemistry, Seufferheld and colleagues showed that the polyphosphate storage structure in bacteria (they analyzed an agrobacterium) was physically, chemically and functionally the same as an organelle called an acidocalcisome (uh-SID-oh-KAL-sih-zohm) found in many single-celled eukaryotes.
Their findings, the authors wrote, “suggest that acidocalcisomes arose before the prokaryotic (bacterial) and eukaryotic lineages diverged.” The new study suggests that the origins of the organelle are even more ancient.
The study tracks the evolutionary history of a protein enzyme (called a vacuolar proton pyrophosphatase, or V-H+PPase) that is common in the acidocalcisomes of eukaryotic and bacterial cells. (Archaea also contain the enzyme and a structure with the same physical and chemical properties as an acidocalcisome, the researchers report.)
By comparing the sequences of the V-H+PPase genes from hundreds of organisms representing the three domains of life, the team constructed a “family tree” that showed how different versions of the enzyme in different organisms were related. That tree was similar in broad detail to the universal tree of life created from an analysis of hundreds of genes. This indicates, the researchers said, that the V-H+PPase enzyme and the acidocalcisome it serves are very ancient, dating back to the LUCA, before the three main branches of the tree of life appeared.
“There are many possible scenarios that could explain this, but the best, the most parsimonious, the most likely would be that you had already the enzyme even before diversification started on Earth,” said study co-author Gustavo Caetano-Anollés, a professor of crop sciences and an affiliate of the Institute for Genomic Biology at Illinois. “The protein was there to begin with and was then inherited into all emerging lineages.”
“This is the only organelle to our knowledge now that is common to eukaryotes, that is common to bacteria and that is most likely common to archaea,” Seufferheld said. “It is the only one that is universal.”
The study lends support to a hypothesis that LUCA may have been more complex even than the simplest organisms alive today, said James Whitfield, a professor of entomology at Illinois and a co-author on the study.
“You can’t assume that the whole story of life is just building and assembling things,” Whitfield said. “Some have argued that the reason that bacteria are so simple is because they have to live in extreme environments and they have to reproduce extremely quickly. So they may actually be reduced versions of what was there originally. According to this view, they’ve become streamlined genetically and structurally from what they originally were like. We may have underestimated how complex this common ancestor actually was.”
Their study appears in the journal Biology Direct.