[whutsurnaym]

The questions you're asking sound to me like they're based around progressive evolution (or maybe teleology? I don't remember the specifics) -- basically the idea that organisms evolve towards some goal.

The example that I heard in school was that of a giraffe's neck. It seems reasonable enough to say "giraffes evolved long necks in order to reach food sources in taller trees", but this is usually a kind of misleading shorthand for the much more accurate "some proto-giraffe acquired a mutation that increased the length of its neck, that change increased its likelihood of procreation (possibly by allowing it to reach food sources shorter-necked proto-giraffes could not, therefore allowing it to survive in harsher conditions), and that mutation was passed down to its offspring".

It's easy to make the mistake in thinking "organisms change their characteristics to survive", but that's applying intent where there is none. Organisms' characteristics change naturally through mutation. Those organisms either live to reproduce or they don't. Mutations that increase the chance of reproduction are more likely to get passed down to future generations. Over a long enough time period you end up with a lot of distinct species that evolved naturally and entirely accidentally.