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The Obfuscation of r-selection and K-selection Theory
Eric Lee
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19 min read
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Aug 28, 2024
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Salmon are r-selected species
A female salmon typically lays between 1,500 and 10,000 eggs depending on species and health of the female. Only a few (0 to 10) of these eggs will survive to be adult salmon. A population maintaining its size only produces one adult from each parent on average (two adults from each spawning pair), but it will be higher in some years and lower in others.Adult salmon live in the ocean, travel up to 1,000 miles from their home stream, and grow for 2 to 7 years (4 to 5 average) before returning to (usually) their stream of birth to spawn and die. If the carrying capacity has not changed nor the level of predation/disease hasn’t changed (e.g. by modern commercial/recreational overfishing), then on average 2 of the 1,500 to 10,000 eggs will live/persist long enough to spawn and die a natural death, meaning 0.13% to 0.02% survive, or there is a 99.87% to 99.98% die off of hatchlings (babies). Modern humans believe they are a K-selected subspecies of Homo sapiens [those few who can view themselves as animals].
Humans are K-selected species
Humans may be defined as fully bipedal apes, as distinct from facultative bipeds (‘knuckle walkers’, e.g. sifakas, capuchin monkeys, baboons, gibbons, gorillas, bonobos and common chimpanzees). The first hominin was, until recently, thought/guessed to be Sahelanthropus and Ardipithecus, but recent evidence shows they were facultative bipeds. Thigh bones of the six-million-year-old Orrorin tugenensis supports the view that Orrorin was bipedal (and a good tree climber).Members of the subfamily Hominini (hominins) is contested. Some include chimanzees and/or gorillas, but I’m a biped chauvinist, and instead of creating a new sub-subfamily, I include only obligate (mostly bipedal) bipeds among fellow humans, unlike all truly modern humans (e.g. Elon Musk) who view only the expansionist form of Homo sapiens sapiens that arose about 76k years ago in Africa as human. Nor am I one of the other extremists, the sinocentric racists who view only mongoloid modern humans as truly human (as real humans).
Normal humans, those prior to the expansionist form and those who persist to modern times (<10k San, <400 Hadza with pre-expansionist culture intact), are K-selected humans, i.e. the rest (the 99.9999% modern human majority) are not, i.e. everyone who could read this claim.
For over six million years normal humans, people of place, endeavored to live within limits (carrying capacity). Half of offspring died before becoming reproductive adults because sexual reproduction creates variation. Variations of what works tend to mostly not work as well, but some work better, so if those of the next generation who don’t function as well as their parents generation die, their death (or non-reproduction) is the NECESSARY price paid for the few who are marginally more adapted to persist than their parents, such that the frequency of their genes increase in the next generation and, long term, humans persist (evolve).
Normal humans usually have 4 or 5 offspring per pair bond, but if there has been a depopulation event, e.g. by natural catastrophe (that decreases environmental productivity or by disease), normal humans can increase their fertility rate to 6–7 births per adult female average to exponentially increase their population to recover from the depopulation event (and then return to 4–5 depending on death rate to maintain their population within carrying capacity).
Oh, but our ancestors didn’t have IUDs, birth control pills, latex condoms, and didn’t abstain from vaginal intercourse, so they couldn’t do any family planning like modern humans often fail to do, so they just had one baby after the other, right?
No. They were normal (evolved, adaptive) K-selected humans.
Normal human mothers nurse for 3–5 years. Half of offspring naturally die, and so having four makes two replacements maintaining a stead-state population. Nursing for 4 years creates (naturally) a state of lactational amenorrhea (not ovulating, no periods, no pregnancy). After nursing ends, menorrhea restarts, and in about a year there is (naturally, no planning implied) another baby (a 5 year interval — on average each woman has 4 or a bit more offspring that maintains the population and by unintentional culling of random variation, each generation is as functional as their parent’s generation or slightly more so, unlike in all devolving modern societies).
Oh, but what if the climate changes and environmental productivity increases, food is more abundant, fewer hours are needed to gather it and food quality is high…, well then, normal hominins stop nursing sooner, have a baby every 3–4 years, and the group’s population grows. At some point items normally on Nature’s shelves start to go missing, food become more scarce, the time to gather it increases, stress levels raise, and like normal mammals, normal humans respond to increased stress (General Adaptation Syndrome, GAS) that decrease fertility rates (nurse 5 years or 6 years between offspring to reduce fertility rate) in complex ways (whatever works is selected for by evolution including stress-induced adult death which is, totally all forms of stress related physical/mental/social dysfunction, the number one cause of death among modern adult humans, i.e. the diseases of civilization).
In normal humans, women stressed by increasing lack of abundance nurse longer, birth fewer young, and population declines until the food pickings are again comfortably within the limits of enough. If over-abundance should arise, offspring are weaned sooner and the dance with Mother (Nature) goes on as the millennia pass.
Modern humans are not normal animals. Most cannot think of themselves as animals, much less normal animals, and would rather die than live like animals. For most, this is their foreseeable future (most die and the others live as evermore denormalized animals during a prolonged as possible dissolution process).
Modern humans are storytelling animals, as all normal humans were 76k years ago. Normal humans came to tell stories consistent with their biology and ecology, what had worked during the prior six million years of hominin evolution. Naturally they told stories that reinforced their K-selected biology/ecology. When resources became scarce, a conscious story of why women should nurse longer might be told, and a K-selected culture emerged to reinforce what their mammalian ancestors knew as K-selected animals. Thus did the increasingly complex verbal behavior (storytelling) allow humans to live long and prosper (enough) within limits.
Humans differ, though not in kind, from other land animals in the complexity of their verbal behavior (that of cetaceans is more complex). Their storytelling brains told adaptive stories, but their acquired superpower created the possibility of telling maladaptive, pathological stories, stories of things not out there, stories of error, ignorance, and illusion that feel ever so good in the short term to believe.
And thus did the expansionist form of human arise who told stories that contradicted all foundational tenets of K-culture that all normal humans presumed to be natural and normal, as their ancestors had always thought and thereby had persisted in a prosperity of enough as the millennia past.
New stories were told of ‘growth is good’, ‘more is better’, ‘us vs them’, of ‘winner take all’, and of why we omniscient conquerors must celebrate our rightful gains. We who were no longer a people of place could take from nature and pseudo-pretend humans, view all as a resource for the taking, and Earth as an illimitable plane Lord Man could endlessly expand upon. Africa was 20k years in the taking. Eurasia took another 10k-30k years and it took 39k years to begin the taking of the Americas. It took 50k years to begin the taking of the Pacific islands, but by 700 years ago the last continent (Zealandia) was taken.
Oh, but Earth is not an illimitable plane. Sorry about that.
But in modern times no one Omniscient Conqueror has claimed the planet yet, so conflict between empire builders persists. While all land areas had been taken by the 18th century, the resources within had not. There was a planetary larder of fossil fuels for the taking, energy to empower the taking of all other nonrenewable natural resources, and it was the Indo-Europeans who first used coal to grow empire, empowering an Industrial Revolution that could turn fossil fuels into food via a Green Revolution even faster than the human, livestock, and pet populations could grow (until the 21st century) by turning 99% of vertebrate land animals into humans, livestock, and pets.
The change from a K-selected from of human to an r-selected form of human had two preconditions: technology and an ability to tell stories about the world. Stories about the world were adaptive as evidenced by the ability to tell them was selected for.
If language was a ‘superpower’ that enhanced our inclusive fitness (and could again), it contained the potential for telling stories about the world, forming a worldview, that could be mistaken for the world. If likely stories are believed in, the mutation was a belief-in-belief memetic mutation that allowed mis-taking our view of the world for the world. Abstracted beliefs, social constructs, an ability to tell stories AND BELIEVE in them as if the stories are true, are the thing told of, is the mutation of ideology (abstracted systems of belief), a cognitive pathology.
If an omniscient storyteller came to tell stories of why rule by an alpha-male was decreed, then the first conquest culture was formed. When scarcity arose, the people in the next valley and its resources were taken. When scarcity arose again, the solution was always the same — look towards the horizon and envision more resources for the righteous taking. We modern humans are nearing the climax of our righteous succession.
Shaka and storyteller may have repeated on a grand scale a pattern that started on a small scale (<100 ) 76k years ago.
Toovercome foresight intelligence, the normal human’s ability to ask ‘and then what?’ after the taking, the conquest, required ideology to justify. Sometimes it takes religion (religious ideology). Sometimes it takes politics (political ideology) to believe insapient claims, asserted as presumed verities, e.g. human exceptionalism and supremacy. All expansionist consensus narrative are variants of one narrative: the ideology of the necessary primacy of the human enterprise as technology enables.
The expansionist enterprise was dependent on ideology and technology — on serving both. The condition of dependency selects for domestication. Wolves who became dependent on humans became dogs, wolf domesticants. Humans whose persistence was dependent on technology and ideology became modern human domisticants who added money to what they depend on and serve.
Wolves are K-selected. They do not overshoot carrying capacity and kill all prey animals (they don’t have guns), degrade their habitat until it cannot support them to prosper for a time. Dogs are r-selected to breed continuously without limit until there is no kibble, e.g. feral dogs in the Chernobyl Exclusion Zone (now inhabited by about 120 wolves and all remaining feral dogs are fed by humans who work in the CEZ — the dogs may never evolve to persist without being dependent on humans). Modern humans and dogs are r-selected to expand, to maximize growth, consumption, their numbers. Modern humans took 12 years to go from 7 to 8 billion people who would rather believe than know.
The absence of modern humans is needed.
Some modern humans are more r-selected than others. The genetic diversity of women is about three times that of men because at various periods in the last 75k years a few men did most of the breeding. Some 64% of modern European males can trace their paternal lineage back to just 3 male progenitors, conquerors who, after killing the adult males not turned into slaves, bred hundreds of women each whose many sons endeavored to do the same if on a lesser scale.
Those having the most reproductive success spread their genes and also memes (language, culture, religion, worldview, mindset) globally to, by the mid-20th century, form the Euro-Sino Empire of fossil fueled development served by a monetary expansionist culture. Elon Musk, an Indo-European and African, until recently, convinced he would retire on Mars and has many adorers, but his cohort are storytelling animals who would rather believe than know.
Think about salmon, normal humans, and modern humans (and dogs). That’s all you need to know about r/K-selection theory. The r-selected species are carrying capacity blind and maximize the number of viable offspring. The K-selected are foundationally carrying capacity sighted.
In sea turtles, r-selection is what works for long term persistence. Dogs, r-selected wolf domesticants, have no long-term existence apart from humans unless some renormalize as the dingoes in Australia did.
Modern humans have no long-term existence apart from technology and ideology (and money) which selects for over expansion/growth, which is a dynamic that selects for extinction long term (as a metastatic form of pancreatic cell selects for its dissolution). If modern humans side-step extinction in the next 50 to 50k years, it will be to become Borg-like expansionists within the Milky Way, their first galaxy for the taking.
Other traits associated with r-selected and K-selected species are a distraction. The belief that modern humans are K-selected is a necessary illusion — as if modern humans were recognized to be r-selected, their worldview based on zero-order humanism, on the ideology of the necessary primacy of the human enterprise, would be fatally contradicted (but better now than later).
Ifwhat is important to understand is how/why organisms vary in size at birth, growth patterns, age and size at maturity, number, size, and sex ratio of offspring, age- and size-specific reproductive investments, age- and size-specific mortality schedules, length of life, then forget about r/K-selection theory and focus on life history theory. It’s all about the traits, right?
In life history theory, yes, and also in obfuscated r/K-selection theory. The ‘K’ is German for ‘carrying capacity’, which may be mentioned, but largely ignored/obfuscated as needed. To not understand what your salary or Anthropocene enthusiasm depends on, requires distractions, i.e. ‘traits’.
K-selected species are characterized by traits such as:
- Low reproductive rate
- Large body size
- Long lifespan
- Late maturity
- High parental care
- Specialist diet
- Low dispersal ability
- Low population growth rate
- Specialist niche
r-selected species are characterized by traits such as:
- High reproductive rate
- Small body size
- Short lifespan
- Early maturity
- Little parental care
- Generalist diet
- High dispersal ability
- High population growth rate
- Generalist niche
Oak trees are large, long lived, and therefore often featured as an example of a K-selected plant and dandelions are r-selected. A dandelion plant can produce between 50–150 seed heads per year, with each head containing 54–400 seeds on average. This means that a single dandelion plant can produce between 2,170–23,000 seeds. An oak tree can produce 2,000 to 10,000 seeds each year or 10 million acorns in a lifetime to on average replace itself. Oak trees, like sea turtles, are large, long lived r-strategists.
Rats and mice are cited as r-selected mammals, which they manafestly are not. If mice have larger litters than rats or even dogs, it is a adaptation to high predation. If introduced by humans to a predator free enivronment (e.g. an island) mice may lack an evloved ability to limit their population like reindeer did on St. Matthews Island and other wolf-free islands they were introduced to. The reindeer on St. Matthews went into overshoot and their population collapsed to island extinction. Polynesian rats have reached numerous islands, with or without human assistance, and have evolved adaptations, i.e. they don’t do the overshoot to collapse thing like reindeer do.
John B. Calhoun’s first experiment involved wild Norway rats, presumably full function normal K-strategist rats (not rats of NIMH) who had never been subject to overdensity living and loss of functional behaviors, and thus avoided overdensity population overshoot. Doing so is adaptive and has been selected for (in rats who have been a eusocial species far longer than humans who are not as highly evolved).
Calhoun released five female rats and enough males in a 10,800-square-foot (1000 m²) outdoor pen with predator exclosure and supplied them with illimitable (to them) food and water and such necessities as Calhoun (he wasn’t a rat, so what would he know?) thought to provide. He observed them over a 28-month period starting in 1947 (Calhoun was forced to retire from the National Institute of Mental Health (NIMH) in 1984 but continued to study his data until he couldn’t as he had a life-driven purpose to do so).
Per Calhoun’s best guess their population could have theoretically grown to 5,000 rats in the enclosure (based on the density domestic rats tolerate), but didn’t. Their population climaxed at about 200 and then stabilized at around 150. As noted, these were normal K-selected Norway rats with culture/behavioral repertoire intact. They did not disperse evenly about the enclosure as individuals, but self-organized into twelve or thirteen colonies of about 12 rats each. The Dunbar number for Norway rats is about 12, and the maximum viable colony density was about 12–13 for the size of area they inhabited. Stress between colonies, conflict/fighting, was evident.
Rat fertility was stress reduced to maintain the population within evolved K-selected norms for Norway rats that allowed their ancestors to avoid overshoot. Domestic r-selected rats and mice (and r-selected dogs and modern humans) lack the genetic/memetic information need to live within limits.
A response to stress is still evident (e.g. increased diseases of civilization including mental illness and the ‘demo graphic transition’, which is an observation, not a theory, that may be secondary to stress on modern women who are increasingly educated to serve the economy apart from home to pay for daycare if any children happen for some inconvenient reason). The GAS response, however, is not adaptive enough to have prevented overshoot:
The socioeconomic-political system serving modern schooling system is also a mis-education system that of necessity must serve zero-order humanism, the ideology of the necessary primacy of the human enterprise and its (somehow) sustainable future.
Khan Academy offers an example:
r-selected and K-selected population growth strategies | High school biology | Khan Academy
[Correction: r/K-selection is a persistence theory, not a population growth strategy.]Transcript
- [Narrator]What we’re going to do in this video is talk about different population growth strategies for different species. And think about if we can come up with a broad categorization or if there’s a broad categorization already out there for us.
So, we see that there are species like elephants that are long lived, in the wild. An African elephant can live roughly as long as a human being can 50, 60, 70, in some cases, 80 years. You also have things like killer whales that are also long lived.
You have things like human beings that live a pretty good long time compared to other things in nature. You have things like gorillas that are also reasonably long lived, live many, many, many decades.
Now there’s also other patterns that you see on these large mammals. They tend to be large. Especially, if you think about compared to very small things in the animal kingdom. They tend to not have a lot of children every reproductive event, I guess you could say, at every time they give birth. So few few children, children at a time And it takes them a while to give birth to those children. And then they take care of them for a while.
Now, the other end of the spectrum, you have some of the things that we have here. You have amphibians like frogs, you have insects. You could imagine small fish, bacteria, mosquitoes that are more short-lived. Short lived. They tend to be smaller. And they tend to have a lot of children at a time.
So lots of children at a time. Just an example, a frog or what do you see here is this is a spiders coming out of an egg sack. Frogs or spiders, they can lay in many cases, thousands of eggs at a time. And they’re not really dependent on any one of those eggs, necessarily surviving.
Many of them will be killed off by predators but as long as a few survive then the next generation, you can imagine, they get to reproduction and then they’ll lay thousands of eggs.
And they’re shorter lived. A frog could live a few years. Some insects might live anywhere from a few days to a few years. You have things like bacteria that can have an even shorter life span. So, when biologists or ecologists look at this, they say it looks like there is a spectrum over here.
You have these large long-lived animals that have a few children at a time. And really the limiting factor on their population is how dense their population is. At some point, these animals are going to compete for resources with each other. And that’s true of things like human beings.
And the other end, you have these things like spiders or frogs, instead might be limited on their reproduction by environmental factors like how moist or dry it is, how hot or cold it is. And so generally speaking folks have attempted to classify these types of species.
They call them K-selected. I’ll talk about where the K comes from in a second. And they talk about these types of species as r-selected. And where these letters come from, is there, there’s a general idea that if we draw a little axis here, time and then draw up axis here, population on the vertical axis, most species that when there’s not a lot of them, and they’re not limited by resources they will grow exponentially like this.
Now, when you go into the math of it, that rate of growth is usually denoted by the letter ‘r’, and you could see where this r-selected is coming from. And what that r is, how large it is, is determined by a species biotic potential.
And biotic potential just means in a given environment, how quickly can they reproduce? What percentage of those are able to get to maturity so that they can reproduce, et cetera, et cetera?
And so you could imagine the higher the r, the faster this exponential growth goes up. Now, at some point you’re going to be resource constrained. And some, there’s some carrying capacity. And so let’s say this is the carrying capacity here, and let’s call that K.
And the reason why we use K instead of C is K comes from a word for capacity in German. So, at some point you’re gonna have so many things that you’re not gonna have enough resources to support more. And so your population would flatten out something like this.
And so, generally speaking biologists have categorized these left categories of species as K-selected. The amount that you have, the amount of population is going to be determined by the resources that are there, the carrying capacity in the environment, while things like frogs and mosquitoes and bacteria and spiders, you view more as r-selected.
They’re gonna grow exponentially at their biotic potential, but that biotic potential is gonna be determined by how hot or cold or wet or dry or other environmental factors. They’re not gonna get to such a high density, that they’re really competing with each other.
Now, as you can imagine with most categorizations, nature is not that clean that things are always going to be on the left side, or always gonna be on the right side. For example, things like turtles lay a lot of eggs but they live a very long time.
It’s also worth noting that there’s no value judgment that one strategy is better than the other. They’ve both been successful. The fact that these species exist today, show that they have worked well.
It is worth noting that invasive species tend to be more r-selected. They will just grow and grow and grow, and gonna be limited by the environment and not as much by each other.
While K-selected species are often the ones that are most effected by invasive species.
Now, the last thing I wanna highlight is, what we just talked about as population growth strategies. And that can sometimes be confused with niche strategies where are there certain species that are generalists, that can occupy many different niches while there’s certain species that are more specialists.
Here, we’re just talking about generally speaking, how do species tend to grow in population? While when we talk about niche strategies, we’re gonna talk about the types of niches they feel in order to get their resources. And we’ll talk more about all of that in future videos.
The End
— — — — — — — — — — — — — — — — —
For K-selected species, overshooting the upper limit never has a long-term payoff.
Evolution selects for those who avoid overshoot like the plague.
Modern r-selected humans are a one-off plague-phase species.
K-selected humans would not exceed carrying capacity to avoid degrading the biotic community they depend upon to persist long term (there ancestors had persisted long term). Modern r-selected humans did/do, hence are not normal humans. They and/or their progeny will pay the overshoot debt that is now locked in. Sorry about that.
Ecology
Written by Eric Lee
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A know-nothing hu-man from the hood who just doesn't get it.
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