There’s an old ‘joke’. How fast do you have to run to escape a hungry tiger? The answer is merely “faster than your slowest friend”.
In evolution, we often talk about the survival of the fittest, but that’s not really it. It’s really survival of the mostly adequate. It doesn’t matter if the solution is optimal, just that it’s better than the alternatives.
It’s not about winning, it’s about not losing.
In human sports, there can be only one. The Superbowl, the World Cup, the World Series, etc. etc. etc. They all have one winner. One team (or competitor) that has bested all (or most) of the other teams. There’s another saying, “Second is the first loser.” That’s the attitude of people. There has to be a winner and everyone else loses.
In fact, it seems that most human endeavors have a clear cut winner and everyone else is a loser. But that’s not how things work for the rest of life. Consider a herd of zebra stalked by a lion pride. The lions will make one kill, eat it, and spend the next day or two sleeping. In this case, there isn’t one winner and everyone else loses, but there’s one loser and everyone else wins.
It’s an important distinction and one that is hard to get across to people.
When we think about evolution, we tend to think “survival of the fittest” and that a small number of highly fit organisms tend to do most of the breeding. That’s just not the case. In reality, we have a very few losers and everyone else is breeding. We see this in fish, in plants, in animals of all kinds. Even in bacteria. It’s not a universal position, but pretty close to it.
A recent conversation with the latest creationist to visit this blog left us unable to convince him that natural selection doesn’t result in death. In reality, it’s the lack of reproductive opportunity that results in natural selection. Think of that lion pride. The single male lion (or reproductive age) in the pride guards his females and offspring jealously. When a competitor turns up, either he wins and takes over the pride or he loses and runs away. But neither animal dies.
What this creationist person was saying is that animals that are spayed or neutered, woman with hysterectomies and men with vasectomies are really dead. Which, even thinking about it for a few seconds, is pretty stupid.
But there’s anther point to this. It’s that evolution doesn’t provide the optimal solution… or even require it. The non-loser just has to be good enough. Think about that male lion again. He will do some hunting, but the females do 80+% of the hunting. The males are for fighting each other and defending their pride. It’s a different skill set… just like game hunting is a different skill than speed target shooting.
So, is the male that wins the fight and control of the pride the best possible animal? Probably not. He may not even be the best possible male lion. Maybe he challenged an old, weak male. Regardless, he’ll kill the cubs and mate with the females. He’s certainly good enough for now.
This is especially important because many people think that natural selection reduces diversity… and it does. A tiny little bit. But in the not-a-loser model, even alleles that are not the best possible version have a good chance at being passed on to the next generation.
So, there’s two models here.
- Survival of the fittest where a small number of highly fit individuals do most of the breeding.
- Survival of the adequate where a large number of non-horrible individuals all breed.
What do we expect to see in each?
In the first model, we would expect to see a lack of diversity. The majority of the organisms in a population will be directly or indirectly related to a few, highly fit individuals. What’s interesting about this model is that it actually has a very high rate of evolution.
This is because as the highly fit genes spread through the population, the majority of the offspring will be highly fit. This, in turn, means that, to stand out, one individual will have to be much more fit than all the other highly fit individuals.
In the second model, we have a large number of highly diverse individuals in the population. The rate of evolution is slower. The population is more resistant to major changes in the environment, due to that diversity.
Now, what do we see in the real world? We see the second model… for most organisms.
This doesn’t take into account genetic bottlenecks, like the Cheetah. Cheetahs are very homogeneous on a genetic level, not due to fitness, but to a near mass-extinction.