Can man be replaced by machine?

The idea that man, or anything similar and ungodly can be immortal is not a new one. It has been around for hundreds of years in myths and stories. But now, it does not seem that far off, with the biological and mechanical replacements for body parts, that people are already becoming part machine. But should this happen? To what extent? How much can you replace before we are not really ourselves anymore? Will we want the next generation, newly improved with mechanical parts, to live forever?
To answer most of these questions would include the consideration of many ethics. However, if one had all their arms and legs replace with mechanical ones, another person’s liver replaced their own, even their heart failed and they were given a new one. With all of these body parts replaced, with such a small percentage of the body they were born with still with them, sustaining life, are they really themselves? Is there a reason that many animals, after they reproduce, die off so that they can let the next generation live? Some think so, that there are reasons why even the ‘immortal’ in myths can die of a broken heart, that there is an evolutionary reason that we live long enough to see our children prosper, and then it is their turn to take care of us as we age, and our bodies fail, in the untampered cycle of life.
To change this way of life would be very dangerous. Where would these people live? How would they be fed? How will the Earth sustain life for all of these people? Granted yes, if scientists could live forever, cancer, heart disease, AIDS, all of these diseases and causes of mortality could be abolished by new discoveries. But with a planet of only a certain amount of resources, and only that space to sustain life as we know it or can conceive it; to open up the possibility of eternal life, or as close as we can get to it, would be to open Pandora’s box in the worst way, to let out all the evils of humanity all over again on the unsuspecting new generations to come.