A Primer on the Tree of Life (Part 1)

Discovery Institute ^ | May 5, 2009 | Casey Luskin

[GodGunsGuts]

A Primer on the Tree of Life (Part 1)

Evolutionists often claim that universal common ancestry and the “tree of life” are established facts. One recent opinion article in argued, “The evidence that all life, plants and animals, humans and fruit flies, evolved from a common ancestor by mutation and natural selection is beyond theory. It is a fact. Anyone who takes the time to read the evidence with an open mind will join scientists and the well-educated.”[1] The take-home message is that if you doubt Darwin’s tree of life, you’re ignorant. No one wants to be ridiculed, so it’s a lot easier to buy the rhetoric and “join scientists and the well-educated.”

But what is the evidence for their claim, and how much of it is based upon assumptions? The truth is that common ancestry is merely an assumption that governs interpretation of the data, not an undeniable conclusion, and whenever data contradicts expectations of common descent, evolutionists resort to a variety of different ad hoc rationalizations to save common descent from being falsified.

Some of these ad hoc rationalizations may appear reasonable — horizontal gene transfer, convergent evolution, differing rates of evolution (rapid evolution is conveniently said to muddy any phylogenetic signal), fusion of genomes — but at the end of the day, we must call them what they are: ad hoc rationalizations designed to save a theory that has already been falsified. Because it is taken as an assumption, evolutionists effectively treat common ancestry in an unfalsifiable and unscientific fashion, where any data that contradicts the expectations of common descent is simply explained away via one of the above ad hoc rationalizations. But if we treat common descent as it ought to be treated — as a testable hypothesis — then it contradicts much data.

The Main Assumption
As noted, the first assumption that goes into tree-building is the basic assumption that similarity is the result of inheritance for a common ancestor. That is, except for when it isn’t. (And then the similarity is purportedly said to be the result of convergent evolution, etc.) But even if we take this claim at face value — that similarity is the result of inheritance from a common ancestor — let’s recognize it for what it is: a mere assumption. But are there other possibilities?

I'll explore more problems with the tree of life and other possibilities in a series of four total posts in this series.

Reference Cited:

[1.] Perry Mann, "The Dinky Insect That Helps Demonstrate Darwin's Theory," at http://www.huntingtonnews.net/columns/090427-mann-columnsmanntalk.html (April 27, 2009).

[GodGunsGuts]

Good morning...Ping!

Will post rest of series as they become available—GGG

[MEGoody]

Anyone who takes the time to read the evidence with an open mind will join scientists and the well-educated.

That's the typical line with the subtext being, if you don't believe as we do, you are stupid and uneducated or just plain looney.

Sorry, but that kind of 'argument' just doesn't cut it with me.

[dmz]

That's the typical line with the subtext being, if you don't believe as we do, you are stupid and uneducated or just plain looney.

And if the "evolutionists" don't believe as you do, we are atheist, materialist, God-denyers intent on destroying western civilization as we have known it for the last 2000 years. On purpose. Willfully. With full knowledge of the ramifications of what we are doing.

And we kick small dogs as well.

I'd say there is room for improvement in how these 2 groups deal with one another.

[Angostura]

This article carries its own assumption that “the truth is that common ancestry is merely an assumption that governs interpretation of the data”.

I would argue that actually there’s a tremendous amount of data that has lead to this conclusion, so it is an assumption based on what we’ve seen. However it is not an unassailable one. If there were compelling evidence that life arose multiple times, that wouldn’t actually be a problem for modern evolutionary theory. In fact it would be fascinating and probably get some researcher a Nobel gong.

These ‘ad hoc rationalisations’ that the article mentions are merely observations of what happens in nature. Take convergent evolution. We know that the hornbill and the toucan are only very distantly related from DNA evidence and yet they look remarkably similar, presumably because they are adapted to similar life styles. Similarly, we’ve actually observed horizontal gene transfer occur, it’s not just something that’s been made up. And yes, rates of evolution do presumably differ based on selection pressure.

When you look at how many aspects of the basic genome are conserved across different species almost identically, I’d say the evidence for a common ancestor is pretty strong and so most scientists use it as a current working assumption.

[GodGunsGuts]

Arguing is one thing, presenting the evidence is quite another. If there truly is a tremendous amount of data demonstrating common ancestry, the Evos sure do one heck of a job hiding it!

[Alamo-Girl]

Thanks for the ping!

[verity]

Seems to me Creationism is based exclusively upon faith and not on hard evidence.

And, I do not kick small dogs. ;-)

[chris_bdba]

I’ve had people tell me that it really isn’t just a theroy because it can’t be proved or disproved. When I remind them that if it were a fact it would be called that they resort to the insults. Peer pressure at it’s finest and it works really well on people with no critical thinking skills.

[MEGoody]

I'd say there is room for improvement in how these 2 groups deal with one another.

I would agree.