What works survives and propagates.
What doesn't, dies and doesn't propagate.
What does and doesn't work is determined by the environment at large.
Natural selection.
There is also the effect of consciousness on evolution, such as the process of migration. One may not be suitable for a hot environment, so rather than stay and die, by not being selected by natural selection, you migrate to where it is cooler, so you can be selected. During the ice ages, animals were forced to consciously migrate to find places where they can be selected. The carnivores, following their food supply, made selection for them a moving target.
Darwin's theory of natural selection has logic to it based on natural potentials that push and pull on life. Science added a genetic randomizer variable that is not that well thought out. Random change will do more harm than good. Take a complex machine like an automobile and randomly move parts around. Or randomly move the lines of computer code around and see if you break it or innovate it. The odds are you will break it long before you improve it. It makes no conceptual sense.
To me a more complete and logical model of evolution would also include changes in natural selection itself, for any given environment. A forest fire can alter the environment and change who can and will be selected. This selection process will then gradually change as the forest grows back; larger animals appear.
An Ice Age can change the rules for selection, in all environments, so collective biological change is needed. The current theory is more like unnecessary change as though selective pressures are always the same. Adaptation to changing environments adds the brain to the selection formula, by using the brain to alter, adapt or migrate to where the weather suits your clothes.
If you look how/where various races of humans settled, at one point in time, this selection was mutual; good place to thrive and be selected. Places like China and India do a lot of propagating. The West tends to push population control, since they do not feel as selected. This could be due to the fast pace of change in free market materialist cultures that imports too much stuff.
I tend to believe there is cause and effect for genetic change. It may look random, but often it is about timing, where changes appear too early or tool late, relative to the changes in natural selection. It would be like moving to a new part of the country, to get a good job, and then the economy tanks. Now this once optimize change, is not optimize, and looks like a random mutation due to lack of selective advantages. If this had been done a year before, the story may have ended differently; selected to stay at the job.