Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Universal common ancestor


Related Topics

In the News (Fri 14 Jun 19)

  
  LUCA. Who is LUCA? What is LUCA? Where is LUCA? Definition of LUCA. Meaning of LUCA.
In biology, the theory of universal common descent proposes that all organisms on Earth are descended from a common ancestor or ancestral gene pool.¹
A theory of universal common descent based on evolutionary principles was proposed by Charles Darwin in his book The Origin of Species (1859), and later in The Descent of Man (1871).
The universality of the genetic code is generally regarded by biologists as definitive evidence in favor of the theory of universal common descent (UCD) for all bacteria, archaea, and prokaryotes (see Three domain system).
www.knowledgerush.com /kr/encyclopedia/LUCA   (829 words)

  
 Common descent - Wikipedia, the free encyclopedia
In biology, the theory of universal common descent proposes that all organisms on Earth are descended from a common ancestor or ancestral gene pool.
This theory is now generally accepted by biologists, and the last universal common ancestor (LUCA or LUA), that is, the most recent common ancestor of all currently living organisms, is believed to have appeared about 3.5 billion years ago (see: origin of life).
The universality of the genetic code is generally regarded by biologists as definitive evidence in favor of the theory of universal common descent (UCD) for all bacteria, archaea, and eukaryotes (see Three domain system).
en.wikipedia.org /wiki/Common_descent   (1091 words)

  
 Last universal ancestor - Wikipedia, the free encyclopedia
Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend.
Also LCA (last common ancestor) or LUCA (last universal common ancestor).
The last universal ancestor already had all of the properties that are shared by all currently living organisms, such as a (prokaryotic) cell structure, DNA, the modern genetic code and mRNA, tRNA and ribosome mediated transcription.
en.wikipedia.org /wiki/Last_universal_ancestor   (172 words)

  
 - A Critique of ''29 Evidences for Macroevolution'' - Part 2 -
If universal common ancestry is true, then some organisms will have structures the function of which was lost or diminished in the course of the organism’s evolutionary history (“vestiges” of the organism’s evolutionary history).
The suggestion that universal common ancestry would be falsified by finding “vestigial structures” in an organism that were not present in that organism’s alleged ancestors, as depicted in the standard phylogeny, is incorrect (in that it is based on a false premise).
There is nothing about the hypothesis of universal common ancestry that requires any particular manner of reproduction, let alone one in which embryos either recapitulate the ontogenies of their ancestors or pass through stages representative of their evolutionary history.
www.trueorigin.org /theobald1c.asp   (6772 words)

  
 Ralph Dumain: "The Autodidact Project": "The Universal" by E. V. Ilyenkov
Also understood as "common" is that which exists apart from these two individuals, precisely as a thing or yet another individual, like common ancestor, common—one for two (for all), field, common motor‑car or kitchen, common friend or acquaintance, and so on, and so forth.
Among the "features" of the common ancestor who continues alive amidst his posteriors, one is bound to suggest an ability to generate something contrary to himself—the ability to generate both, a big man (relative to himself) and, on the contrary, a little man (again relative to himself).
The universal ("concrete‑universal") is opposed to the sensuous variety of particular individuals, in the first place as the latter's own substance and the concrete form of their interaction, rather than to intellectual abstraction.
www.autodidactproject.org /other/ilyenkv4.html   (6792 words)

  
 LAST UNIVERSAL COMMON ANCESTOR -   (Site not responding. Last check: 2007-10-14)
A theory of universal common descent based on evolutionary principles was proposed by Charles Darwin in his...
Algorithms for computing parsimonious evolutionary scenarios for genome evolution, the last universal common ancestor and dominance of horizontal gene transfer in the evolution of prokaryotes Algorithms for computing...
The quest for a universal common ancestor is made possible by the...
universal.fazs.com /index.php?k=LAST-UNIVERSAL-COMMON-ANCESTOR   (1263 words)

  
 Common ancestor - EvoWiki   (Site not responding. Last check: 2007-10-14)
Identifying common ancestors is one of the tasks you have to do when systematically ordering known species.
Usually it is these recent common ancestors that biologists/paleontologists are concerned with, and the most recent link between later species would be the last common ancestor (LCA) while the LCA of all contemporary life on Earth is known as the Last Universal Common Ancestor (LUCA).
A fossil of the common ancestor or a related form is a transitional fossil.
wiki.cotch.net /wiki.phtml?title=Common_ancestor   (281 words)

  
 A response to Ashby Camp's "Critique"
Common descent does not predict that these structures must be identical, just that the similarity must be statistically significant, and that there must be viable intermediates between the variations.
And, as a deduction of common descent, the prediction of biological universals is testable, confirmable, and falsifiable.
The hypothesis of the universal common ancestry of species is not the same as universal common ancestry of proteins and/or genes.
www.talkorigins.org /faqs/comdesc/camp.html   (17232 words)

  
 Evolutionblog   (Site not responding. Last check: 2007-10-14)
Actually, the universality of the DNA code, and the universality of the cellular machinery used to translate that code, are evidence for a universal common ancestor.
I would answer that common descent is merely an extrapolation of processes which are readily observed, such as birth and heredity, while separate creation requires the invocation of a designer who is difficult to explain (where did he come from?) and for whom we have no independent evidence.
Similarly, universal common ancestry could not survive the discovery that in some organisms DNA is the molecule of heredity while some different molecule is at work in other organisms.
evolutionblog.blogspot.com /2004/08/hunter-part-2.html   (2341 words)

  
 Natural History: The Search for LUCA - Last Universal Common Ancestor   (Site not responding. Last check: 2007-10-14)
We infer the existence of this Last Universal Common Ancestor--or LUCA--from the many features shared by all organisms, most notably the unique code that translates the language of DNA into the language of proteins, the things that actually do all the work inside cells.
This undoubtedly tiny organism was the last common ancestor of all present-day eukaryotes (organisms possessing cells with a nucleus).
Forterre argues that his scenario of moving from a complex eukaryotelike common ancestor to a simpler but more efficient prokaryotic system is more appealing than the classical hypothesis that views prokaryotes as the more primitive organisms.
www.findarticles.com /p/articles/mi_m1134/is_9_109/ai_67410993   (1330 words)

  
 Articles - Biology   (Site not responding. Last check: 2007-10-14)
In development the theme of universal processes is also present, for example in most metazoan organisms the basic steps of the early embryo development share similar morphological stages and include similar genes.
This "last universal common ancestor, that is, the most recent common ancestor of all organisms, is believed to have appeared about 3.5 billion years ago (see: origin of life).
The common genetic and developmental mechanisms of animals and plants is studied in molecular biology, molecular genetics and developmental biology.
www.bird-center.net /articles/Biology   (2055 words)

  
 Should We Stop Criticizing the Doctrine of Universal Common Ancestry? Wells, Jonathan A.
For example, Darwinists have argued that all living organisms are descended from a common ancestor, and that the universality of the genetic code is important evidence for this.
The truth is that MOST of the evidence cited in support of common ancestry at the levels of kingdoms, phyla and classes has had to be explained away to protect the idea of common ancestry.
It seems to me, however, that the doctrine of universal common ancestry is primarily a deduction from naturalistic philosophy rather than an inference from biological evidence.
www.arn.org /docs/wells/jw_criticizingcommonancestry1103.htm   (1182 words)

  
 29+ Evidences for Macroevolution: Phylogenetics
The macroevolutionary prediction of a unique, historical universal phylogenetic tree is the most important, powerful, and basic conclusion from the hypothesis of universal common descent.
Several nodes are indicated, such as the "fly" taxon node and an internal node that represents the common ancestor of mice and humans.
For example, the common sample average as an estimate of the mean of a Gaussian distribution and the least-squares fit of a line to a set of points are both maximum likelihood estimators.
www.talkorigins.org /faqs/comdesc/phylo.html   (5162 words)

  
 "My Name is LUCA -- The Last Universal Common Ancestor" by Anthony M. Poole, Ph.D.
LUCA is short for Last Universal Common Ancestor, and it is from this 'organism' that every living cell on the planet has descended.
Nevertheless, universal features are important because they describe a 'lower limit' from which to build upon, and importantly, all these attempts converge on agreement insofar as concluding that LUCA was quite complex.
Universal protein families and the functional content of the last universal common ancestor.
www.actionbioscience.org /newfrontiers/poolepaper.html   (7113 words)

  
 BioMed Central | Full text | Algorithms for computing parsimonious evolutionary scenarios for genome evolution, the ...   (Site not responding. Last check: 2007-10-14)
Thus, comparative genomics might potentially undermine the very idea of a universal species tree because, inasmuch as HGT is shown to make a substantial contribution to genome evolution, no tree can, in principle, fully reflect the course of evolution of species [7,9,11,18,19].
The unexpected outcome of this analysis is that HGT might have been as common in the evolution of prokaryotes as lineage-specific gene loss, particularly at the early stages.
The topology of the species tree in Figure 5 was derived from the concatenated tree of universal ribosomal proteins [24] and is close to the apparent consensus of various genome-tree approaches [30].
www.biomedcentral.com /1471-2148/3/2   (11194 words)

  
 "What is the last universal common ancestor (LUCA)?" by Anthony M. Poole, Ph.D.
LUCA is not the name of a famous scientist in the field; it is shorthand for Last Universal Common Ancestor, a single cell that lived perhaps 3 or 4 billion years ago, and from which all life has since evolved.
The question they are asking is, "which features of the archaea, bacteria and eukaryotes can be traced back to their common ancestor, LUCA?" This should be a very simple task -- simply compare all three groups and choose the features that are common to all.
Some of the genes that are not universal can be added to LUCA because clues to their origin can be found by looking at what they do.
www.actionbioscience.org /newfrontiers/poolearticle.html   (2296 words)

  
 Figure 1   (Site not responding. Last check: 2007-10-14)
The figure shows how the number of ancestors of two people alive today builds up in a manner that is close to exponential.
The same applies in searching for the ancestor of all living humans (universal ancestors are represented as grey balls).
In standard models, the number of generations back to the common ancestor of a particular allele will be of the order 2n, which is much longer ago.
www.nature.com /nature/journal/v431/n7008/fig_tab/431518a_F1_lgnd.html   (204 words)

  
 [No title]   (Site not responding. Last check: 2007-10-14)
In many phylogenies, the modern groups most closely related to the common ancestor of archaea and bacteria are hyperthermophiles that live in places where temperatures exceed 80°C—for example the hot springs of Yellowstone National Park in Wyoming and hydrothermal vents on the ocean floor.
After all, the genetic code and much of biochemistry is universal, so perhaps LUCA can be revealed by finding a set of genes for basic biological functions that is present in all organisms.
Peter Antonelli and Solange Rutz at the University of Alberta in Edmonton wrote equations describing the competition for resources and the sharing of genes and biochemicals that would have gone on in such a world, and found them to be mathematically unstable.
www.nature.com /news/2004/040216/pf/427674a_pf.html   (2411 words)

  
 Evolution without speciation but with selection: LUCA, the Last Universal Common Ancestor in Gilbert’s RNA world
We address another aspect of the original LUCA: that one stage in the evolution of the universal common ancestor in which only selfish genes were present, at first without an organismal or genealogical identity.
In the days of the early ancestor most of these functional compartments were effectively isolated thanks to lipid membranes, across which most materials moved selectively.
These evolvable changes in general were not abrupt; however, we are investing the early ancestor with the capacity not to abrogate some apparently dangerous mobile elements that enter via lateral transfers, and to assume oligonucleotides that could have been part of transitory semiloads (semilethals).
funpecrp.com.br /gmr/year2003/vol4-2/gmr0070_full_text.htm   (4558 words)

  
 LUCA   (Site not responding. Last check: 2007-10-14)
The majority vision today is more that of a common ancestor resembling either bacteria or archaea, and for some, that of a creature intermediate between prokaryotes (cells without nuclei) and eukaryotes (cells with nuclei).
The term 'last common ancestor' could be used (and is in effect) for all groups of organisms.
This work should open on the inventory of proteins common to the three domains, that is to say present similarities of sequence which one could reasonably suppose to all be derived from the same common ancestor (In technical terms, these proteins are said to be homologs).
www-archbac.u-psud.fr /Meetings/LesTreilles/LesTreilles_e.html   (3805 words)

  
 Stephen E. Jones: Testimony: Why I (a Creationist) Accept Common Ancestry
What I mean by "common ancestry" is universal common ancestry, that all organisms that have ever lived, including humans, share a common ancestor and are therefore all related to each other by common descent.
My original position on common ancestry was that I did not accept it, and argued vigorously against it on the Internet for about a year, until in 1995 I was convinced by the evidence and a series of `coincidences' that common ancestry was true.
So Dolly and her offspring have a common ancestry with all other sheep, even though there was human intelligent designer intervention in the process.
members.iinet.net.au /~sejones/cmnctsry.html   (7487 words)

  
 (ootips) Single Ancestor
A universal ancestor is the natural place for behaviour that applies to every object.
Anyone who feels that a single ancestor structure is not useful, necessary, etc., might be enlightened by a look at the class Object in any Smalltalk implementation.
If the common ancestor needs to be changed for any reason, every program in the system must be rebuilt.
ootips.org /single-ancestor.html   (866 words)

  
 LAST UNIVERSAL -   (Site not responding. Last check: 2007-10-14)
scientist in the field; it is shorthand for Last Universal Common Ancestor, a single cell that lived perhaps 3...
A revision of Period IX, chapters 1-4 of her Universal history, with the addition of chapter 5, and Period X, chapters 1-5, carrying the history to March 2, 1855.
He now thinks that "the Last Universal Common Ancestor was not a...
universal.fazs.com /index.php?k=LAST-UNIVERSAL   (1189 words)

  
 The universal ancestor -- Woese 95 (12): 6854 -- Proceedings of the National Academy of Sciences
The universal ancestor -- Woese 95 (12): 6854 -- Proceedings of the National Academy of Sciences
A genetic annealing model for the universal ancestor of all extant life is presented; the name of the model derives from its
Biologists have long subscribed to the powerful, unifying idea that all life on Earth arose from a common ancestor (1).
www.pnas.org /cgi/content/full/95/12/6854   (5562 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.