Its called adaptation, your genetics make changes to best suit your enviroment without your control, you don't get a say so, am I right?
No, you're not right. You are stuck with the genetics you're born with.
Imagine a bunch of chameleons.
Some have a long tongue gene A and some a short tongue gene B, some have independent eye gene X and some have eyes that aren't independent gene Y. So, you have AX, AY, BX and BY chameleons.
When they reproduce each passes on their genes, for example a AX mating with a BX will produce offspring that are either AX or BX, both parents providing the X and the offspring having a 50/50 chance of getting a long or short tongue, A or B gene.
The ones with A and X genes have a competitive advantage as they are better hunters than the ones with B and Y. Because they are better hunters they are more likely to live to produce offspring and thus more likely to pass their genes on to the next generation. The chameleons with AX really lucked out, they have both advantages and a higher percentage of them will live to pass on their genes than any other combination. The AY and BX chameleons don't have it all, but they each have a strength. The poor BY lizards are going to face an uphill battle though, and some will win it, but a higher percentage of them will fail and die without reproducing than the other combinations.
Gradually, over many generations, the B and Y genes will disappear from the gene pool due to this natural selection. No matter how hard the poor BY chameleons try or how much they need them to survive, they will never have long tongues or independent eyes.