It has always been the gene that evolves, not the whole organism.
Evolution of the gene as the inseparable component of being.
Sometimes to understand Evolution, it's enlightening to study it at a molecular level. The smallest individual component of existence is the gene. A gene, in this sense, is an immortal and autonomous component, which can code for a specific function in its host organism.
If we observe this carefully, organisms, including us humans, are somewhat vehicles of the gene. However, these collective genes have to work together to ensure the survival of each individual gene. What I mean by this is that, take a human body, for example, several genes work together to make a functional circulatory system and others the digestive system yet others a reproductive system but also collectively making up a human being, and if we choose to go deeper, the gene ensures the survival of a species.
Additionally, most genes do not identify with one species or Kingdom. You can actually find the same gene in a human being, spider or virus with the same function, perhaps coding for a certain enzyme. Just this versatility is why for example, gene expression of a human insulin gene in a Bacterium can produce functional human insulin as if it was made in the human body.
Organisms act as vehicles of genes from one generation to the next. Once the organism passes genes, the parent vehicle goes into senescence so that it can take care of the potential future vehicle. So what is immortal is the gene, not us, the mere vehicles. But this immortality comes at a price.
Survival of the fittest gene…
Nature’s iron rule is ‘Survival of the fittest’. Only the fit gene is allowed to live.
If Nature notices a weakness in a certain system, it favours processes/pathways that eradicate such a system. In Nature’s bible, it's ‘Survival of the fittest’ all the way. It’s up to the gene to find mechanisms that make it relevant in each and every circumstance it is subjected to. Else it becomes outdated and replaced by emerging ‘fit’ genes.
What it means is that each and every live organism is an embodiment of a collection of successful genes. To Nature, there is nothing Good or Bad; it just is. Whether the gene urges a cheetah to eat a baby antelope or a plant to make food from light, if that mechanism ensures survival, then in Nature’s eyes, it's good to go.
The Biophilosophy
At the instinct-level, each and every organism is governed by genes in a way that ensures passage of the gene to the next generation. If we could study life in the eyes of the gene as the indivisible component of life, then there wouldn’t be confusion about whether the virus is a living or non-living particle. Even Evolution, in general, would be very easy to comprehend because it’s the gene in play. The decisions we make in life show us what our genes have decided with us as vehicles.
