Argument #2: Evolution Of Species

[Chas]

Origins and DNA evidence
Biologists use the DNA sequences of modern organisms to reconstruct the tree of life and to figure out the likely characteristics of the most recent common ancestor of all living things — the "trunk" of the tree of life. In fact, according to some hypotheses, this "most recent common ancestor" may actually be a set of organisms that lived at the same time and were able to swap genes easily. In either case, reconstructing the early branches on the tree of life tells us that this ancestor (or set of ancestors) probably used DNA as its genetic material and performed complex chemical reactions. But what came before it? We know that this last common ancestor must have had ancestors of its own - a long line of forebears forming the root of the tree of life - but to learn about them, we must turn to other lines of evidence.

Just because organisms have DNA with common genetic materials doesn't prove all species have a common ancestor.

You don't actually understand the DNA evidence, do you?

DNA is a string of pairs of purines (Adenine and Guanine) and pyrimidines (Cytosine and Thymine), two of each.
DNA codes for making amino acids.
The code is determined by triplets of these pairs.
Since each location can be one of four combinations (A-T, T-A, G-C, C-G), there are 64 possible triplets. These triplets code for 20 amino acids and a start/stop processing code.

The odds of arriving at that particular coding are about a million million million million million to one.

Every organism on earth uses the same code. Every. Single. One.

That clearly means common ancestry.