R and K Strategies

Each species on the earth employs a different strategy to ensure that they leave offspring
behind before they die.  This strategy is usually reinforced by the organism’s genes and so
it is difficult for most organisms to deviate much from their inherited strategy.  There are two
fundamental types of reproductive strategies and they can be described as antagonistic –
meaning that when you are reliant on one you normally use less of the other.  These two
strategies are the K strategy and the r strategy.  K strategists are often said to be “K-
selected” and r strategists are said to be “r-selected.”

Biologists often refer to a “spectrum” or continuum that helps us distinguish one organism’s
reproductive strategy from another.  All living organisms are supposed to fall somewhere on
this continuum between the two extremes (r and K).  Also, organisms can be differentiated
from one another in terms of their relative reliance on one strategy over the other.


r ____._________._________.______.________.__________._________._________._______.____ K
bacteria      mollusks      insects      fish      amphibians      reptiles      mammals      apes      humans


R strategists usually create an abundance of offspring in the hopes that a few will make it.  
These species usually have a very short maturation time, often breed at a very young age,
have a short lifespan, produce many offspring very quickly, have young with high mortality
rates and invest relatively little in parental care.  The parents do not focus on passing down
memes, units of cultural information, to their young.  Instead the behavior of the young is
determined by their genes.  The young are precocial, meaning that they often can make it
on their own without any instruction from their parents.  Examples of r-selected species
include bacteria, insects, and fish.

K strategists are very different in that they attempt to ensure the survival of their offspring by
investing time in them, instead of investing in lots of them.  It is a reproductive strategy that
focuses on quality over quantity.  K strategist have relatively few offspring and make an
effort at being good parents.  Their young are altricial meaning that they cannot survive on
their own until they reach adulthood.  This extended period of maturation is used for
memetic transference- the parents teach the young so that they can go on to reproduce
themselves.  K strategists are known to have a relatively long life span, produce relatively
few offspring, the offspring have low mortality rates and the parents provide extensive
parental care.  The offspring are also relatively intelligent so that they can internalize the
lessons from their parents.  K-selected species include elephants, apes and whales.  
Humans are perhaps the most K-selected because their young are truly helpless- they
necessitate a full two decades of parental care and tutelage and the parents usually only
produce one offspring at a time.

An organism’s behavior determines its chances for reproductive success and therefore the
rstrategy is by far the more robust strategy.  The behavior of an r strategist is dictated by its
genes which are naturally selected over geological time.  This means that r strategists are
self sufficient and their behavior rarely goes wrong.  The behavior of a K strategist on the
other hand is completely dependent on the lessons from its parents and so extreme K
strategy is very risky.  I believe that there are certain mechanisms that might help mitigate
the risk inherent in the K strategy.  

To read my theory on cognitive impairment and meme utility
click here.



Altrical: adj.
The condition of being helpless or dependent on external support.  Dependent on parents
for food.

Meme: noun
A unit of cultural or social information that is transmitted by behavior or by observation.  A
lesson that is transmitted from one mind to another.

Precocial: adj.
The condition of being self sufficient or independent.  Capable of walking shortly after birth
and of leaving the nest within a few days.
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