What are mitochondria?
Mitochondria are found inside virtually all eukaryote (animals, plants, fungi, protists, etc.) cells in huge numbers, and their primary task is to
produce energy for the cell. Like their hosts and bacteria, they are bound by a double lipid membrane, and indeed, they even carry their own DNA
molecules, and reproduce independently of the host cell.
Although there's no scientific consensus about the exact way how mitochondria became a part of us, it's a fact that they were once, about 1.5 billion
years ago, free-living alphaproteobacteria. The image below depicts the many models there are for the origin of eukaryotes (notice they all agree on
the origin of mitochondria, i.e it was an alphaproteobacteria of some sort):
The problem for creationists
As many here no doubt know, phylogenetic trees depicting the relationship of animals, plants, fungi, etc. have been derived from nuclear genes (genes
that are encoded by nuclear DNA). Creationists deem these relationships false, and often claim that there is a mechanism that at some point prevents
change from happening (the artificial micro vs macro separation), i.e. they claim that common ancestry is impossible. The image below depicts a
phylogeny that is derived not from nuclear DNA genes, but from mitochondrial DNA genes:
As you see, all mitochondria (names with colors) derive from one branch of the tree and this is supported by a bootstrap value of 100%, which makes
their common ancestry a scientific fact. A level down, mitochondria and Rickettsia (alphaproteobacterial order) are grouped together, which points to
their common ancestry exclusive to Bradyrhizobium (this particular node is not so well supported). A level further down still groups mitochondria,
Rickettsia, and Bradyrhizobium (another alphaproteobacterial order) together with that 100% bootstrap value, making their common ancestry a scientific
The thing is, trees derived from nuclear DNA and mitochondrial DNA depict the same relationships. Is this not undeniable proof, that the divide
between micro and macro evolution only exists in the minds of creationists?
edit on 12-4-2012 by rhinoceros
because: (no reason given)