What evidence for proteins is there for evolution?

Question

I know there is evidence, I'm just not sure what it is.

Answer 1

Comparing selected proteins, evolutionists hope to show not only phylogenetic relationships but also a "molecular clock" that will provide a relative time table for evolution. For example:

alpha chain of hemoglobin differs between horse and man by about 20 amino acids. Evolutionists believe that the horse and man "diverged" about 100 million years ago THEREFORE, the evolutionary rate of hemoglobin is ONE amino acid per 5 MILLION years. This rate is then extrapolated to other differences and in this way a "phylogenetic tree" is established complete with DATES!

Answer 2

Proteins show enormous features of common descent.  The major mechanism for this is gene duplication.  This is a process that has observed.  There are large families of proteins that share common structures such as the immunoglobulin superfamily.

The most striking feature, however, is homology.  If you compare the same protein in different species, the number of differences not affecting function increases with the degree of relatedness based on the anatomically derived phylogenetic tree.  As this holds true for nonstructural genes such as digestive enzymes, it is independent confirmation.