Evolutionary Survival

Non-theistic evolution would have many chance elements, but natural selection, as it is called, would not bring about new species immediately, nor would it necessarily result in what is optimal instead of minimally sufficient.  If unguided evolution happened, yes, there is still an uncaused cause by logical necessity, and the two are not contradictory, just as an uncaused cause creating the universe and abiogenesis creating life from materials in the universe are not contradictory.  Theism does not exclude many things that are popularly mistaken as antithetical and vice versa.  Biblically, abiogenesis would not have occurred if Christianity is true, but that is a different issue than what is being focused on here.

Why would there be imperfect adaptations to the environment of an animal if natural selection is about increasing the chances of survival and reproduction?  A plant that succumbs to a given disease does not have a gene that grants immunity.  A species of fish with poor vision does not have a gene that brings better visual "hardware" for the eye and nervous system, and its correlating phenomenological sense of vision would suffer (it just might not need excellent sight or any sight at all).  Some things might die because of their limitations before they can reproduce at all.  Tradeoffs between one characteristic and another aside, there is nothing about evolution that itself requires perfection in behavioral/survival outcome or the traits used to obtain it.

As long as an organism is just effective or fortunate enough, by as much as a sliver, it has the chance to reproduce, and if it gets to do so, then its genes and corresponding physical traits (phenotypes) can be passed on.  It does not need to be "ideally" fit to survive through physical ability or mental fortitude one way or another if other members of its species are less equipped to survive, such as by having some crippling disability or happenstance greater susceptibility to sickness, or if some chance disaster eliminates many others while leaving the creature in question alive.  Again, nothing more than the bare minimum is required to survive here.

The concept of macro-evolution is about gradual changes from generation to generation.  It is not the idea of one species directly giving birth to a totally different species or even a small number of generations producing a different species.  Non-theistic (or angelic or extraterrestrial-influenced, etc.) evolution is not presided over by outside forces and is not even about giving one animal anything more than what is absolutely necessary to get by, and it would by nature lead to chance mutations.  The applicability of various traits to survival, in contrast, would not be total chance because they would or add to or detract from the probabilistic likelihood of life extension or the passing on of genes.

If macro evolution did occur, then it would not need to be the case that we would observe every kind of surviving species and individual within each category has perfect, universal adaptations.  In this case, there would not even be something to set one individual animal physically apart from another to give it a survival advantage.  What barely permits a living thing to stay alive and perhaps procreate is enough.  Whether survival objectively matters is an issue hinging on whether morality exists and what its obligations are, which is really a matter of whether the uncaused cause has a moral nature and, if so, what it is like.  Survival opportunities and chances, however, are affected by physical traits, and only creatures that reproduce could pass on their traits.  This is natural selection, which is on this level true even if it was independent of macro-evolution, and it does not involve the immediate development of high quality traits unless guided by some sort of mind, for all it would need would be something just useful enough.