Explain how a gene pool and biological evolution are related

The ones that are able to survive pass on their genes to the next generation. Bye doing that they pass on certain traits to the next generation causing them to inherit those traits and develop new ones and that prosses repeats for thousands and millions of years and that's how they are able to evolve.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.