Evolution through natural selection: The survival of the most fit

But "fittest" when talked about by non-biologists is often a bit of a misunderstood term. It does not necessarily mean the strongest, or smartest, or most beautiful. It means the creature best adapted to fit its particular niche and multiply will usually be the kind to dominate it. There is a subtleness that is lost here when regular people talk about it that implies that evolution as a very individualistic process. However, that isn't strictly true; that's a view that's over 60-100 years out of date depending on how solid the evidence you want to talk about is. Like anything in the real world, evolution is a little more complicated than people may expect, and many factors can be considered.

I'll talk about a few mechanisms here. I would also throw in evolutionary game theory but due to time constraints I will not explain it.

Inclusive Fitness

Evolution can result in the selection of altruistic traits. Consider, for instance, an animal which is compelled to scream in warning when it spots a predator. The scream will make it obvious to the predator where that particular individual actually is, presenting an unnecessary risk that might ultimately end that particular individual's genetic line. However, if the warning scream causes his kin to run and scatter (who also have the same gene complex compelling them to scream when a predator is about), the behavior is preserved and reinforced compared to those who stood quiet and did nothing while the predators picked them off one by one.

Parenting might also be considered an example of inclusive fitness; raising your offspring to better ensure that they survive to maturation is on an individual level a potential detriment to the parent's own survival, but over a longer term is an assurance that your genes and behavior continue to be passed on. Of course, that's not the only way to do things; a lizard or an octopus will not parent at all. Many species can solve the problem of too many prematurely dying offspring by simply pumping out more offspring than any selection filters can gobble up.

Such traits can be reinforced up to the point that the end up being endangerment to the kin who carry it.

Group Selection

Traits which solely benefit the individual don't always win the game of life. Not only can the behavior of an individual be selected against, but the behavior of organizations of individuals. The organization of social groups in everything from insects, to birds, to wolves, and primates can give clue to this fact. Groups which cooperate and work together can often end up better surviving and filling a niche better than those that do not.

You can even see this on the level of human society: cultures that have societies whose cultural norms are more centered around the benefit of the whole generally end up with better survival rates than those that only consider the individual.

Coevolution

One species interacting with another can benefit both, resulting in both species evolving in tandem to better work with one other. Flowers and insects, along with fruits and animals, are the most obvious examples of these. Flowers become strongly scented to better attract insects to spread their pollen while insects themselves became more suited to identifying friendly bodies.

Coevolution also goes the other way, with two antagonistic forces like bacteria and fungi engaging in an ever changing evolutionary arms race to defend against one another.

Bottom line: it's complicated

There are many more mechanisms which can be discussed - including ones which might result in a generally negative social impact such as Hamiltonian spite, or ones that might create a generally negative impact to individuals such as selection shadows.

Hopefully, however, this has given an insight into some mechanisms you may have not known about, which can show that we, as well as most other species, are not necessarily entirely governed by individualistic gains and selfishness, but by also by group benefits (which may not always be necessarily as rosy as some of these examples illustrate either, of course).