To not understand tons of obvious facts in favor of genetic changes we call evolution?
Ok, let's do some Biology 101.
Let's take as example few bird specie with gradual change of beak size (due to mutations and following survival of "fittiest beak" to certain eating function).
Certhidea olivacea: small probing bill, incect eater, feeds in trees.
Camarthynchus palidus: slightly larger bill, incect eater, uses twig or cactus spine to probe incects from cactus.
Camarthyncus heliobates: medium-sized grasping bill, incect eater. Feeds in trees.
Camarthynchus crassirostirs: large crushing bill, cactus seed eater.
How about gradual variations in beak shape among different species of Darvin finches, as correlated by feeding habits?
How about GRADUAL variation of features among apes? Among human races?
Of course, in some examples of "close relatives" there may be even closer similarities (say, in human races) or there may be larger genetic distance between relative species - there are variety of examples. If the distance is very short, they may even interbreed and we then call them one specie. If distance is large, we may even put them in different families. Is this something which is difficult to understand? Is not it self-obvious?
How about different species appearing (and disappearing) at different geological times? Some species emerged 1 billion years ago, some 100 millions, some 60, some 20, some 10, some 1, some now? Many disappeared after few million or tens of million years. The question is - who constantly "makes" them? And out of what?
Out of clay? You sure believe that we, humans (and all other species) were made about 6000 years ago (4000 BC) out of clay, right? But what a confuse - there are human remnants and artifacts which are 10000 year old, 20000, 50000, 100000, 200000, 500000, 1000000, 2 million years old, 5 million, 10 million, 20, 50, 70 million. How about that? And what about the fact that they GRADUALLY look less and less human-like as you go back in time? How about fossiles of numerous other species prior to Holy Bible Creation of them all 6000 years ago? And what about the fact that the inorganic clay is VERY different compound than complex organic molecules we are made of?
What about the fact that ancient fossiles are more and more primitive as you go 1 billion years back, 2, 3, 4 billion? Why are they more and more complex and diverse - like a branches of tree gradually spurring in all directions of complexity with time pass?
What about the fact that as ancient plants start to proliferate, Earth atmosphere which had NO oxygen and plenty of CO2 before that, was gradually (over about 800 million years) depleted by CO2 practically to zero and at the same time oxygen content gradually roze from zero to 20% ?
How about moth in 17-18 century England which had to mutate (change its DNA) from white to black to survive on darkened by mass coal burning polluted birch tree skin (white moth were eaten easily by birds and rare black mutants got upper hand)?
How about now - moth is getting whiter and whiter because of more and more strict pollution control and thus whiter birch bark on which black moth can no longer hide? Sure, DNA of white and black moth is DIFFERENT. By continuing change environment you make a selection of such extreme DNAs which will no longer breed with original DNA (like in the case with some dogs which no longer breed with wolf). Do you DENY that, or you just do not understand how mutation/selection works?
Any high school biology textbook has HUGE and detailed description of evolution - various examples of DNA change: both natural (due to mutagenes and radiation) leading to variety of what we see in the wild now and human engineered/selected. Let me know if you want to learn more about those textbook examples, I can go to the library and fax you chapters with the description of molecular mechanism of DNA replication and mutations.
Would you deny all those FACTS too?