Bacteria and Viruses do not evolve and are misused as examples of evolution.
A Bacteria never becomes more than a Bacteria, and a Virus never becomes anything other than another type of Virus. Mutations and adaptations within
their own genetic limits is not in any way a form of evolution, it is what they are genetically made to do.
A bacteria can no more evolve into a complex cellular organism with a backbone, than a primate could evolve into a human.
ironic considering humans ARE primates but more to the point a more correct analogy would be to compare bacterial evolution with a mammal evolving
into becoming a human as opposed to a primate. the evolution of primates is rather well documented at this point with new discoveries being made every
And on that note, Humans share only 93-95% DNA with Chimps, but share 98% DNA with Pigs.
Are we more related to Pigs than to the proposed ancestor of our lineage?
Not quite. Mammals have most of the same genes for similar biochemical and physiological functions. If you look at the details of the genes …
there'll be differences between them, but they'll still be doing the same kind of function.
It's a little bit like having a Ford or a Holden — it's still obviously a car but a slightly different version.
But while 20,000 similar genes sounds like a lot, only one to two per cent of our DNA actually encodes proteins. Most of the rest is transcribed into
Some RNAs that don't carry the plans for proteins have important structural or functional roles in their own right. Transfer RNAs, for example, ferry
specific amino acids into a growing protein, while ribosomal RNA constitutes part of the factories in cells that manufacture proteins.
But we are only just beginning to understand what many other non-coding RNA molecules do. Some control higher level functions such as the expression
of protein-encoding genes, and some have even been implicated in memory.
Parts of the genome that don't encode proteins tend to evolve rapidly, so you can have significant regions of the genome where there's no discernible
similarity between species. This means many sequences will not line up when you compare genomes between species.
And the further away two species are on the evolutionary tree, the greater the difference.
"If we compare really closely related species, like a human and chimpanzee, we can still see the similarity between these rapidly changing sequences.
If you move further away to the more distantly related pig, so many changes in the DNA will have occurred that it is no longer possible to recognize
that the sequences were ever similar.
Depending upon what it is that you are comparing you can say 'Yes, there's a very high degree of similarity, for example between a human and a pig
protein coding sequence', but if you compare rapidly evolving non-coding sequences from a similar location in the genome, you may not be able to
recognize any similarity at all. This means that blanket comparisons of all DNA sequences between species are not very meaningful.
11-10-2013 by peter vlar because: (no reason given)