“More than 150 years ago, Darwin proposed the theory of universal common ancestry (UCA), linking all forms of life by a shared genetic heritage from single-celled microorganisms to humans. Until now, the theory that makes ladybugs, oak trees, champagne yeast and humans distant relatives has remained beyond the scope of a formal test. This week, a Brandeis biochemist reports in Nature the results of the first large scale, quantitative test of the famous theory that underpins modern evolutionary biology.
The results of the study confirm that Darwin had it right all along. In his 1859 book, On the Origin of Species, the British naturalist proposed that, “all the organic beings which have ever lived on this earth have descended from some one primordial form.” Over the last century and a half, qualitative evidence for this theory has steadily grown, in the numerous, surprising transitional forms found in the fossil record, for example, and in the identification of sweeping fundamental biological similarities at the molecular level.
Still, rumblings among some evolutionary biologists have recently emerged questioning whether the evolutionary relationships among living organisms are best described by a single “family tree” or rather by multiple, interconnected trees—a “web of life.” Recent molecular evidence indicates that primordial life may have undergone rampant horizontal gene transfer, which occurs frequently today when single-celled organisms swap genes using mechanisms other than usual organismal reproduction. In that case, some scientists argue, early evolutionary relationships were web-like, making it possible that life sprang up independently from many ancestors.
According to biochemist Douglas Theobald, it doesn’t really matter. “Let’s say life originated independently multiple times, which UCA allows is possible,” said Theobald. “If so, the theory holds that a bottleneck occurred in evolution, with descendants of only one of the independent origins surviving until the present. Alternatively, separate populations could have merged, by exchanging enough genes over time to become a single species that eventually was ancestral to us all. Either way, all of life would still be genetically related.”"
Continue reading at Physorg.com
I knew that conker tree at the bottom of my hill fancies me but now I know why. I’m away to give him some love now. While I’m away I hope that the contents of the box can be revealed as I haven’t seen any update on what it was yet.
Mwah to all my ancestors.
How many times must this be said: That’s not how science works! It didn’t confirm anything. It failed to disconfirm the theory, which is great in its own way. You cannot have confirmation without replication and consensus. This was one study. Even with two decades of such studies, we just say that a theory is commonly accepted, not confirmed.
I promise I’m not arguing semantics here. We use statistical methods to test these theories. Without even looking at the study, I can tell you that there is a chance that this result could be completely in error. Beyond that, if the statistical power was too high compared to the effect size, then they could’ve found the results, anyway.
Please, just stick with the agreed upon terminology. Otherwise you make us scientists into liars.
The long-held obsession with paternal lineage has lead to a distorted view of human familial connectedness. Six degrees of seperation: the network of humanity can be described using a maximum of six nodes between each individual. (I think… hope that is right, not an expert).
We are such a melting pot that our current notions of seperate races and families is an illusion reinforced by our physical differences.
In the long term, we are all the inhabitants of Earth – Earthlings, if you like.
We should also be aware that the network is self-supporting in conjunction with our environmental conditions and that we mess with the links and nodes at our peril.
beautiful picture!
this is inneresting. on the one hand, it makes sense fer there to be one originating life form–it just seems like the simplest way to go. but OTOH, we always seem to be searching for The One Origin of just about everything…so i’m not sure what to make of this kinda speculation.
Ah, but they haven’t checked my genes yet … that would have caused chaos in Darwin’s theory .. and a few more here and there …
The song ‘We Are Family’ suddenly and strangely comes to mind.
I agree with Roz – great pciture!
Any chance of telling us who the artist is or where it’s from?
Thanks, toby
Humm! Evolutionary theory. Someone once tolde me that if the web-like theory was correct we would be able to see evolutionary effects on human beings within our own life times. The trouble with UCA as far as I can see is if it is correct would it not take much longer for all organic matterto reach it’s current state?