What Does Survival of the Fittest Mean?
“Survival of the fittest” means that those who are best adapted to their environment thrive and tend to be favored by evolution due to “natural selection”. It does not mean “only the most physically strong or mentally strong thrive” and it is not the same thing as “the theory of evolution”, although it does pertain to it.
Organisms with any genetic traits suited to survive their immediate environment are more likely to procreate and pass on their genes. This means in nature, over time, a trait that is “fit” for survival tends to become dominate in a species, regardless of whether it is a generally impressive or useful trait or not.
By looking at examples of existing organisms, we can conclude that the genetic traits that make an organism fit for survival can vary widely. They largely depend on external factors like food supply, predators, and environmental changes. Traits can be useful, or they can hinder the ability of a species to survive. In other words, traits don’t have to be traditionally “useful” to be “fit”.
Let’s look at Darwin’s own words (and the 150 plus years of science that fill in the gaps, Darwin wasn’t 100% right, but today we filled in most of the holes) to help us clarify how survival of the fittest, natural selection, and evolution work.
What is natural selection? CrashCourse explores natural selection and survival of the fittest.
TIP: We seen evolution in experiments, both in the lab and outside of it (see Experimental evolution).
TIP: See PBS for more information on evolution or for a rebuttal to creationist arguments see “A big stink at The Big Think: the supposed shortcomings of ‘Darwinism’ touted by a quasi-creationist ‘thinker’”
What is Survival of the Fittest?
“Survival of the fittest” is a phrase first used by Herbert Spencer (not Charles Darwin). Spencer was trying to equate Darwin’s natural selection theory to economic theory. Darwin liked Spencer’s idea and used it in subsequent works (even adding it into later versions of the already published On the Origin of Species starting with the 5th edition).
With that in mind, once Darwin did start using the term “survival of the fittest”, he intended it to mean “better designed for an immediate, local environment” and used it as a way to better describe the mechanism of natural selection in his theory of evolution.
FACT: In a way the meaning of “survival of the fittest” is a matter of semantics and language. Given the ambiguity of the word “fit,” biologists don’t typically use the terminology when discussing evolution.
Why is life on so diverse? How did mitochondria get in eukaryotes? Who put that chocolate in my peanut butter and why is it so delicious? Darwin has the answer, careful not to wildly misunderstand him to justify prejudice and egotism.
What is Natural Selection?
Natural selection is when a species better adapted to a given environment thrives and procreates resulting in them becoming a dominant species. Natural selection also implies that the species less adapted to an environment does not thrive. There are a number of factors that impact natural selection, but over time, the result is an evolution of species.
FACT: Alfred Russel Wallace simultaneously discovered the concepts of evolution and natural selection; he published a paper with Darwin in 1858. This prompted Darwin to publish “On The Origin of Species” a year later.
A video looking at natural selection in detail. There are a number of different things that can impact natural selection beyond an organism’s own gene pool.
What is Evolution?
Evolution is any change in a population across generations. Evolutionary theory is the theory of how organisms evolve.
When natural selection takes place, unique traits become prevalent in a species that separate it from other species. Over time, this can result in two different species that can’t interbreed, but have the same ancestors. Rinse and repeat for billions of years, and that is generally how evolutionary biologists think that every living thing from cells to humans evolved.
In other words: Survival of the Fittest -> Natural Selection -> Evolution.
Evolution. What is it good for? The existence of all life on earth actually. This video explains.
What Does “Only the Strong Survive” Mean?
“Only the strong survive” is a not quite the way natural selection works, unless we use “strength” very loosely to mean “well adapted to thriving in their environment”.
FACT: One of the most common adaptations of an organism is symbiosis when two organisms work together to better adapt to an environment. This is probably how all life on earth evolved. This means cooperation, not strength, is arguably the most “fit” of all traits.
What Does “Fittest” Mean in Survival of the Fittest?
Fittest simply means “most fit for the environment in which in organism lives”.
Imagine an animal that has evolved to live in a small hole to escape a predator. Every X amount of babies born a genetic mutation will take place and we will get an extra small or extra large version of the animal.
Large muscular versions of the animal would be less fit to survive while smaller nimble versions would be better suited for their environment. We may find that the smaller versions of the animal thrive over time, while the muscular one’s go extinct due to their inability to fit in the hole to protect themselves from predators. Over time, we would expect this species to be small and nimble, and not large and strong.
This would be natural selection taking place and resulting in evolution.
A clip of a PBS Documentary on Animal Misfits. Almost all of these animals evolved with bizarre traits, not that they are particularly useful in the long run, but they do reinforce the idea that natural selection is influenced by many factors other than strength.
An example of being “fit” without being strong: All but one species of mole rats lives and feeds underground to avoid predators, given this mole rats are typically small. To be the fittest mole rat you have to either be small enough to fit in the hole or have another solution to vulnerability on the surface of the ground.
The Big-headed mole rat tunnels like other mole rats, but actually eats and lives above ground. How does it not get eaten? It partners with a tiny bird (moorland chat) that warns the mole rat when the big-headed mole rat’s main predator, Ethiopian wolves, are near. In return, the big-headed mole rat digs up grubs for the bird.
To be fair, the mole rat also has some pretty big teeth that can hurt the wolf, so its size and strength aren’t totally irrelevant. Still the point is clear. While most moles survive by being small; the big ones survive primarily through intelligence and teamwork. Being strong is at best a secondary helper trait in the case of the big-headed mole rat.
Traits that Aid Survival
Any genetic trait can be useful depending upon the environment an organism has to survive.
Strength, intelligence, passiveness, cooperation, self-interest, beauty, luck, high sex drives, low sex drives, passiveness, color scheme, empathy, eyesight, taste, ability to feel pain, ability to think, size, shape, ability to sense magnetism, ability to change shapes and colors, flying, swimming, vocal ability, breathing underwater, being able to turn to ice and die for 5 months before coming back to life, telepathy, psychoactive properties, how delicious you are to eat, how big you can outstretch parts of your body, how many horns you can grow, the size of appendages, being able to change into a different animal after dying, what type of built-in defenses you have, if you are poisonous, how well you can transmit hormones, and many other traits are can all be synonymous with “fitness” depending upon the organism and their environment.
Why do you think each of the 25 most bizarre animals became a unique species? Is that weirdness functional? How do you think it relates to natural selection?
There is little indication that strength or selfishness are even desirable traits on average. In fact, there are many examples in which, being the strongest or a lone maverick that only cares for himself is an evolutionary death sentence. Imagine an ant colony where one rogue maverick ant tries to go make it alone? The chances of survival are slim; never mind the chances of procreation.
The truth is, nature is pretty strange. Sometimes seemingly useless traits end up making an animal fit for its environment. Seemingly weak traits like beauty, love, cooperation, teamwork or negative traits like laziness or a low sex drive can all be synonymous with “being fit” to adapt to an environment.
Life on earth is complex, but the principles behind how it works are not.