DNA mutations are basically "random", and that is the assmption in many versions of Evolution theory as to how radical changes in the genome takes place. Most of these are detrimental, but on occasion the odds come out right to create a superior critter.
I put "random" in quotations because there actually is a significant study of randomness. Genuine "randomness" is a very hard thing to find. And it is sought for, because if you can generate genuinely random events or numbers, you can use them to build very strong encryption codes.
"Purposelessness" is something that I would think is a philosophical issue. Or human phycological issue. About whether God has a purpose for His Evolution creation, or for humans, science can say nothing, pro or con. I think He does, but science cannot tell me this.
I think we are pretty much in agreement then.
In a pig's eye they are! Joshi A, Wu WP, Mueller LD. 1998. Density-dependent natural selection in Drosophila: Adaptation to adult crowding. EVOLUTIONARY ECOLOGY 12 (3): 363-376.) This study showed that when these fruit flies are grown in conditions of high humidity the wing phenotype of offspring changes almost immediately to suit the conditions.
You can't tell me that's random chance. That's an environmental pressure that's being applied, and the result is a change in phenotype. It's anything but random.