Obtuse-Venom

Because you are having difficulty. I would recommend reading up on the laws of Entropy as well as read up on Bio-Genesis. Then come back and talk about evolution. As my first statement pertains to both. And no,I am not trying to make you feel bad. Just perhaps a little more information to help you with comprehension. ;-D. It should also give more information pertaining to the original question given above. What causes a species to change over time?. I gave you the answer just in this statement

As to the first question, the statement speaks for itself. As to the second question. Genetic material is only gained/transposed/changed only by a collision with other chemical/genetic material. The organisms original material remains the same unless that happens.

I disagree with you that mutation is random. More so it is finite. I will give a very good explanation a bit later when I get past the noobness of this account. But in brief, the DNA of any organism for that matter. Every living organism on this planet is constructed of three dimensional digital coding. Like zip files, pure data with "ZERO" junk code in every single strand. Line for line, which opens up click by click by click , to become a living biological organism. All of it fitting together like a perfect glove. And deeper inside, the genome, the framework of pure biological software, and precision operating systems. File folders containing actual body plans. Digital instructions coordinating every strand,every cell, every part. Pulling the molecular fabric of every piece together to create a biological masterpiece. Literally written, birthed, into reality itself. From scratch! The intangible controlling the tangible. The living blue print of what you call "you". By the way, so you know. Each DNA generation of a organism cycling down per generation. Losing a bit of DNA from the previous generation. The laws of replication, over and over again.