Today’s falsehood is the idea that individual animals act for the benefit of their own species.
Let me give you an example. When I was a kid, I watched a nature show about cougars. The show ‘documented’ a single female cougar going about doing cougar-things and being generally cougar-like. At one point she had cute little baby cougar kittens.
Then a flood came. The stream near her chosen lair swelled its banks and threatened to drown the kittens. So, she carried one of the kittens up the hill to a new lair. She went back to get the second kitten, and the flood waters were even higher and closer to the den, but she managed to save that second kitten. When she went back to get the third kitten, it was not at all clear that she would make it in time. It seemed inevitable that the third kitten would be carried off to it’s death by the torrent. As the mother cougar approached the flood and all hope seemed to diminish, the narrator said “The mother cougar, driven by an instinct to save her species, searched desperately for any sign of the third kitten, who represented the next generation of cougars.” (Or words to that effect.)
At the last second, the mother cougar spotted the kitten, who had already run partly up the hill, and brought it safely to the lair. (We presume that all kittens always survive, which is why we are up to our necks in cougars.)
Within biology, many of the falsehoods being discussed here actually affect practicing scientists. We’ll see an especially good example of this later with the “reproductive success is maximized by fitness” fallacy. We’ve already seen it with the “Evolution has stopped for humans” fallacy. But the “Survival of the species” fallacy never directly affects actual biologists because it is literally almost the first thing you learn about selection, evolution, organismic biology, or whole organism biology. Individuals act in their own (inclusive) self interest. The appearance of altruism is usually underlain by selfish motives. If there is any group-level selection at all (and most biologists think there is not, or at least not much) it is certainly not operating at the level of the species.
The mother cougar was not trying to save cougars when she desperately searched for the third kitten. She was, rather, doing two things simultaneously.
1) She was, at some ultimate level not cognizant to her in any way, trying to increase the likelihood of the survival of her own genes. Or, more accurately, some of the genes she carried were busy saving themselves, and for this particular event, the other genes were free-riding. During some other episode of her life, perhaps as hunger drives her to hunt, different genes are perhaps busy saving themselves while the others are free-riding. I’m sure you get the picture.
2) She was, at the more immediate, or as we like to say, proximate level, her behavior was a response to some kind of limbic and endocrine attachment syndrome whereby mothers bond to and do things for their offspring, similar to the kinds of deep neurological systems that may facilitate the orientation of offspring to their mothers, and in the case of these kittens, the neuro-muscular system that causes a kitten to go limp when picked up by the nape to be carried by mom, instead of squirming around, flying out of mom’s mouth, and dropping fatally into the rushing river.
That the saving of the individual kittens would possibly help the survival of the species is a side effect of her behavior at both the proximate and ultimate level.
This idea can be tested, and has been tested, both in theoretical constructs and in field studies. It is often possible to construct alternative testable hypotheses, one based on an instinct to help the species, or some other large group, and the other to at selfishly. Below, I recommend texts you may wish to consult for excellent overviews and evidence along these lines.
The bottom line is this: A variant of a gene (an “allele”) that confers a trait that results in group-level or species-level survival or reproduction at the expense of the individual will have lower fitness than an allele that instead confers a trait that results in individual survival or reproduction. One of the classic examples of this phenomenon is the prudential restraint in egg laying among colonial nesting birds.
Some bird species — such as gulls, terns, boobies, and the like — nest communally and from these nests forage for nearby resources to feed themselves and their growing young. So, there may be dozens, hundreds, or even thousands of gull nests on well protected cliffs overlooking the ocean, and the gulls will go down to the ocean (one member of the pair at a time, the other staying behind to protect the egg or chick from the other gulls) to feed, and bringing back food for the mate and/or offspring.
The following has been noted (slightly oversimplified here):
1) The number of eggs that a pair will have in a nest varies, let’s say from 3 to 5.
2) The number of eggs each pair has in a given year is the same, with most of the birds laying 3, 4, or 5 eggs.
3) The number of eggs, higher or lower or median, appears to vary with the availability of resources. When there are lots of resources, more eggs are laid, when resources are scarce, fewer eggs are laid, to the extent that this can be assessed by the birds.
Two different hypotheses have been proposed to explain these behaviors.
A: The birds are practicing prudential restraint for the benefit of the group. By holding back on egg laying, the demand on the local resources will be lowered now and over the near future when the offspring fledge, so there will not be as much competition for resources and more members of the group will survive. This is group selection, and taken just one step more, survival of the species.
B: Individual birds (or pairs of birds, but really, probably just the female) lay the number of eggs that matches some perception about the availability of resources, and the birds are essentially tracking the resources and producing the number of offspring that makes sense, economically/ecologically, that year.
One way to test this is to place extra eggs in a small number of nests. If only a few extra eggs are placed overall (but say one per nest), that will not measurably affect the overall availability of or competition for resources by the group, but it may severely affect the birds with the loaded-up nest. Extra egg experiments have been done, and when extra eggs are added to the nest, the final number of offspring fledged goes down rather than up. In other words, the number of eggs in an individual nest is adjusted as needed for the individual’s fitness, not the group’s fitness.
Another fact worth noting is that if both parents in these colonial nesters leave the nest alone, the neighboring birds tend to eat the eggs or chicks as a snack. So much for survival of the species. One would think that if you could prudentially restraining one’s reproduction as an evolutionary strategy, one would prudentially restrain one’s snacking behavior for the same purpose.
It is interesting to note that the survival of the species fallacy has other forms in other areas that are very important. The survival of the species problem is the same problem as the tragedy of the commons problem. It is also the same thing as the “agency effect” or the “agency problem.” It is also worth noting that the early work on this problem was tied to some of the important early work that moved theory from evolutionary biology over to economics. The economists have been playing with this kind of theory … called game theory … ever since.
An interesting paper representing the overlap between economics and evolutionary biology with respect to this issue is “Economic man and selfish genes: the implications of group selection for economic valuation and policy.” From the abstract:
A basic tenet of socio-economics is that economic behavior is shaped by social bonds and cultural context. A relevant controversy in evolutionary biology is group selection and the related issue of altruistic behavior, that is, behavior neutral or detrimental to the individual but positive for the survival of the group. In this paper we examine the parallel controversies surrounding “economic man” and “selfish genes” with particular emphasis on the policy implications of group selection. We argue for the replacement of standard welfare economics with models of human behavior in the spirit of “consilience” between economic theory and the best available science from other relevant disciplines.
(Source:Gowdy, J. (2004). Economic man and selfish genes: the implications of group selection for economic valuation and policy Journal of Socio-Economics, 33 (3), 343-358 DOI: 10.1016/j.socec.2003.12.026)
As promised, here are a few suggested readings that will cover this topic (and other topics). Most of these are available used.
More Falsehoods !!!
This post is one of a series on the topic of falsehoods. The following is a list of falsehoods posts in order:
- The Falsehoods
- “False Pearls before Real Swine”
- Falsehood: A baby is not the biological offspring of its adoptive mother
- Falsehoods: Has evolution stopped for humans?
- Natural Selection is Survival Of the Fittest (A Falsehood)
- Falsehood: Nature maintains balance.
- Is it a Falsehood that Humans Evolve from Apes?
- The poor and the dark skinned have more babies than the rich and the light skinned
- Acting for the survival of the species (a falsehood)
- Culture Overrides Biology (Another falsehood)
- What is the Placebo Effect, and it it getting stronger?