REPRODUCTION -- HOW DOES IT WORK?

The earth teems with thousands of species of creatures, all doing their best to continue teeming. As discussed above, a species continues by reproducing, by making copies of the members in that species. Species that don't reproduce, for whatever reason, don't survive.
Samuel Butler once said, "The hen is the egg's way of making another egg." There is a much truth in this adage. In the natural world, the egg's vehicle, be it fish, fowl or flower, doesn't matter. What does matter is that the vehicle gets the egg fertilized, hatched, and far enough along in development to have a chance of producing another egg. The egg contains the hen's genes, which combine with the rooster's genes. The genes create from the raw materials of organic life another chicken. That chicken then has another egg. It is not the egg, but the genetic material that the egg nourishes and brings to fruition that is important. It is the genes that must be passed on if a species is not to become extinct.
In addition, the egg wants to have another egg as much as possible like itself. A species is a collection of genetically similar individuals. Since it's the genetic material, the genes, that makes each egg an individual member of a species, the egg wants to pass its own genes on to the next generation.
Of course, to nature the individual isn't important; what is important is the species to which the individual belongs. An examination of nature shows this to be true. Herbivores that are susceptible to predation often herd in large numbers. Fish and insects may eggs in the thousands and millions. Plants produce seeds and spores in the millions and billions. In this way, although individual members of a species may fall to predators or bad luck, the species is safe from extinction.
However, this does not mean that the individual doesn't care about reproduction. In fact, it is the reason for the individual's existence. It isn't the species that carries the genes, it's the individuals in that species that do. This desire to pass on its own genes is why an individual is so concerned with self-preservation. It must personally survive to pass on its genes.
An organism wants to pass its own genes on to offspring. If it didn't want to, it wouldn't care if it reproduced or not. Enough of these individuals, and the species dies out. However, that event is unlikely. Without an instinct to pass on its own genes that individual doesn't, and its lack of an instinct to reproduce dies with it. Those individuals that have the instinct are the ones that continue the species, and therefore breed the instinct into future generations.