A virus's mission is to make as many copies of itself as possible
A successful virus must let its host live long enough to spread the virus. That's odd, though—wouldn't it follow that the most successful viruses would let the host keep living and spreading them as long as possible? Wouldn't that mean we should expect viruses to be on our side in general, since our health is linked to their survival? That depends on what you mean by "on our side." The success of a virus in the long run depends on its ability to replicate without killing its hosts. Of course, that doesn't help you if you're killed by one that hasn't evolved to be "successful" yet. As John Maynard Keynes pointed out, in the long run we're all dead. A virus that spread to ten other people and killed you in the process would be quite successful enough, short term. A virus that immediately killed every host wouldn't be successful, just as a computer virus that instantly crashed every computer it infected wouldn't last long. But longevity of the host is just one possibility for a virus's mission:
A virus's mission is to make as many copies of itself as possible.
Wait a minute—why is that the virus's mission? Do we really believe that viruses have some kind of guiding purpose to their lives? What does it even mean to say that a virus has a mission? Why couldn't a virus just be content with infecting one cell, retiring, and kicking back and watching the endoplasmic reticulum for the rest of its days?
The short answer is: if it did, it wouldn't be a virus as it's defined here. I'm only using the word virus to refer to things that penetrate, copy, possibly issue instructions, and spread. But waving my hands and clinging to the definition is the easy way out. There's a very subtle point here, one that's important to under-stand because it runs through this entire book:
When we look at life from the point of view of a virus, we're not saying the virus is alive, can think, or even has a point of view.
Looking at things from the point of view of a virus just gives us insight into what's interesting about viruses: how and why they spread. When I say a virus's mission in life is to spread, I mean only that when we examine viruses, the interesting thing about them is that they spread. If they didn't spread, we wouldn't call them viruses and we wouldn't be interested in them. We are interested in viruses because their penetrating, copying, issuing of instructions, and especially spreading is a powerful force in our universe. It's fascinating, exciting, and even scary to discover something that, once released, goes off on its own and spreads itself to the world with no further effort on the part of its creator. Saying a virus has a mission in life is a trick to make it easy to understand how it works. It would be equally correct to reverse points of view:
The universe contains many mechanisms for copying and dispersing information, and viruses are some of the things that are often copied and dispersed.
Some of these copying mechanisms are straightforward; others are roundabout. But the viruses we see the most copies of are the ones that those mechanisms happen to latch onto and copy. So given that we're only studying successful viruses, the one thing we know about them is that they are good at spreading. The DNA viruses have found effective ways to spread via the copying mechanisms of our cells.
Mariners had painstakingly mapped the coastlines of the continents. Geographers had translated these findings into charts and globes. Photographs of ...
It's the idea that people living close to nature tend to be noble. It's seeing all those sunsets that does it. You can't watch a sunset and then go off and set fire to your neighbor's tepee. Living close to nature is wonderful for your mental health.
But we can easily extend this hypothesis [that nature has beneficial effects on the physical, cognitive and emotional well-being of individuals] to the conservation of biodiversity. [Ecologists] refer to the extinction of the experience of nature, which they have mainly applied in urban areas. The idea is as follows: from generation to generation, young people live less and less in contact with nature (because there are fewer of them and because their lifestyles limit such contact), at the very moment they are building their identity. The part of their identity that integrates their intimate relationships with their natural environment would therefore diminish from generation to generation. Not because of a lack of education, but mainly because of a decline in opportunities and desires to experience nature without constraint, freely and in their own personal way.
The consequences of this decrease appear in adulthood: with a weaker environmental identity, they are less in demand for nature in their daily lives, they integrate it less in their actions. (...) But if we do not collectively take biodiversity into consideration in our lifestyles, then we will suffer.
Source : Mobilizing against the extinction of nature experience (french), july 2015, Espaces naturels
An inefficient virus kills its host. A clever virus stays with it.