Topic 2.

Really, nothing on Earth can be permanent. Animals and plants evolve and/or go extinct, same for humans. Even through evolution things, like animals aren't permanent because they aren't the same as they were.
People can live with this because it's just part of life, they must accept at some point in time that things can't be forever, infact nothing can. It is rather depressing to think that nothing will ever be the same as it once was but that doesn't mean it will be bad. The view on change is warped because just because something is different doesn't automatically make it bad. Just like coming to terms, or at least understanding, death, impermanence must be dealt with. People realize that dealing with everything constantly changing is better than refusing it or choosing to end their own lives, as morbid as it sounds.
Religion, the idea of heaven and hell, gives people the reassurence they need to get on with their lives. The idea of having something after they die. That idea hasn't changed, although their are several different ideas of what that afterlife is. Humans find extreme comfort in knowing that instead of rotting in the ground forever they will be rewarded and get to carry out a greater life elsewhere. Although it is common to believe that Enkidu was the one punished with death the real punishment was cast onto Gilgamesh for having to deal with the death of Enkidu. Enkidu was the one who was sent to the afterlife and got to carry on whereas Gilgamesh suffered for as long as he did because he couldn't come to terms with the idea of one day he was going to die.