Sexual selection has an interesting aspect that can have a bigger impact than other types of selection.

The interesting thing about sexual selection is its unique opportunity for an especially explosive positive feedback loop. A positive feedback loop is one in which a small deviation in the system leads to increased deviations in the same direction as the original deviation. Predator-Prey arms races are good examples of positive feedback loops from non-sexual selection. A small change in a predator’s ability to run fast can eventually be met with its prey being able to run faster, and therefore leading back to a necessity for increased speed in the predator. This process loops over and over.

But sexual selection can offer an even more explosive positive feedback loop. A male can incur the added costs of extravagant attractiveness, even at the cost of his own life, because he will have increased chances for mating before his untimely death. Running faster will keep the predators at bay, but growing that extra-long tail, for example, will get the attention, or preference of the ladies. As long as the male can mate and preserve its genes, longevity past this point is of no real concern.

Here is where the real explosion comes in. In his book, The Genetical Theory of Natural Selection, R.A. Fisher showed how female preference is a legitimate object of sexual selection. In fact, it is the driving force of sexual selection. In the example of extra-long tails, females with a sexual preference for slightly longer tails will choose males with slightly longer tails. This pair will have male offspring with an increased probability for longer tails and female offspring with an increased preference for males with longer tail. The positive feedback look ensues, and the population of long tail preferring females and long tale having males sees a geometric increase.

Can this example of sexual selection be compared to human sexual selection? Sure it can. I view culture gaining its complexity through replication, variation, and selection. A genetic trait that could have led to increased fitness might have been the ability to imitate. If a neighbor did all the R&D work necessary to come up with a valuable tool, or other idea, it would be very beneficial to imitate his actions rather than have to do the R&D work over again. Male imitators fare better, females prefer imitators, they have male and female offspring that respectively are good imitators and prefer good imitators, there is geometric increase in imitators in population. From there, one can see the beginnings of culture emerging.

One striking aspect of culture is that it exists across generations, transmitted through minds. Adapted traits that favor successful transmission are inherited genetically, but culture itself is not. It is stored within us in our brains as well as outside us in a multitude of mediums. Degrees of variation are observed when components of culture are reproduced from one state of storage to another. And another thing we observe is how not all aspects of culture have an equal chance at being passed into the future. This is the final ingredient in the recipe for natural selection.

Cultural replication is different from biological replication in that biological traits are transmitted in one direction – down generations. Culture can be transmitted up and down, as well as side to side. It is even possible for culture to skip generations, lying dormant, stored in a medium that escapes the attention of a people. The theory of natural selection is medium independent; it has no requirements other than heredity, variation, and selection. As long as these conditions are met, the theory of natural selection is helpful in understanding.

Above, I mentioned the ability to imitate, painting the picture of a gene that results an individual being better at imitation compared to one having an alternative version of that gene. This version of the gene that results in better imitation arose through a mutation, or alteration in the DNA sequence from one generation to another. As ideas and cultural artifacts are passed from storage state to storage state, inevitable changes start accumulating. Some of the changes are slight and others are more evident. Some of the traits take off while others fizzle out.

What makes a cultural transmission more likely to be passed along? In an obvious sense, cultural artifacts that increase a person’s ability to survive and reproduce will fair better than those that do otherwise. This may go a long way to explain how we came to be such cultural replicating machines, but it is not the whole story. Our cultural artifacts are not exclusively beneficial for biological reproduction. Their only requirement is that they get passed along, and some artifacts by have features that boost that chance. One example of this is seen in the many variations of “copy me” found in chain letters/emails, educational institutions, and religions. Cultural artifacts can act to benefit humans, be detrimental to humans, or have a neutral effect.

Using the theory of natural selection, not only have we come to know a great deal about biology, we have come to a deeper understanding. Understanding culture through a natural selection paradigm has a short history but it is certainly our future of untangling the complex web. Ideally, in doing so we will increase our ability to marginalize aspects of culture that cause dangers and unhappiness, and promote an optimally sustainable wellbeing.

Quote:All things are subject to interpretation. Whichever interpretation prevails at a given time is a function of power and not truth.

-Friedrich Nietzche

Truth is only one axis on the multidimensional space of cultural artifacts. Artifacts that have a high rating of truth tend to be near those that have a high degree of usefulness, but this is not always the case. Often traits that appeal to emotions such as sex, fairness, or authority tend enjoy a wide spread existence regardless of truth. Many traits affect transmission, but no single trait is what matters. Through this perspective, what matters is making copies – and that involves fidelity, fecundity, and longevity.

For an entity to be considered a replicator, a copy must be made. A copy must have a degree of accuracy or else one cannot say a copy has been made. There are various methods of transmission that increase fidelity; examples range from rituals to using the aid of symbols and machines. With high fidelity, any of the slight variations that occur will be preserved into future generations. It is fidelity that allows replicators to reap the benefit of the accumulating errors that result in benefit.

Fecundity refers to the “fruitfulness” of a replicator. The faster a replicator can multiply, the more wide spread it can be, and more replicating opportunities can be realized. In addition to this, by having fecundity, a replicator will be able to exploit a wider selection of niches. For the most part, the traits that have been discussed affect fecundity in various ways. The point here is that there is no one single factor, different traits increase fecundity in different environments. A higher fecundity rate can make up for lower longevity.

Longevity matters for very obvious reasons. The longer a cultural replicator exists, the more opportunities it has to make copies. As human culture has evolved through time, methods for artifact storage have gotten better and better. In early human culture, as well as in chimpanzee proto-culture, artifacts are often only available for replication in real-time by watching and imitating others. Through the manipulations of symbols, cultural artifacts increase their longevity by being encoded and stored in mediums that endure. From the painting of buffalo on a cave wall all the way to etching notches in thin metals with a laser.

When giving an effort at determining what is true, it is important to understand how these three factors affect the piece of culture under consideration. People naturally exhibit biases (such as the bandwagon effect) that often escape personal awareness. Understanding “who benefits” and allowing cultural replicator in addition to human as the recipient of the benefit is an important tool in calibrating thought when attempting to understand.

What a great way to think about our actions and thoughts, individually and cumulatively! Fascinating. Great post.

Of course, as we analyze cultural replicators, we are "inside" one (or a billion) even by doing that. Crazy.

I can't help but think of the cultural phenomenon (alcohol) having a huge impact on sexual selection, especially in western civilization. What I am saying is that not all favorable traits are being replicated, in fact, one might say that alcohol has the ability to let not so attractive features be passed down. In this case, does culture selection play a greater role than sexual selection? Also, culture phenomenon of say, antiabortion, can lead to accidental pregnancies going to term, therefore increasing the chances that the one-night-stand with beer goggles leads into gene replication. Again, culture outweighs sexual selection. Is it my misunderstanding, or should sexual selection be the primary motivator? Or, is culture the motivator and therefore requires in depth analysis to discover the trends and possible ways to improve? Probably they are equally important, however, i just outlined two scenarios where culture selection beats sexual selection.

Cultural phenomena do have a major impact on sexual selection. The human female can be quite like the peahen, but instead of desiring a big show-off tail she might prefer an expensive car or jewelry – in addition to attractive looks (and so on). Various cultural phenomena, such as binge drinking and over-extended lines of credit offer an effective way to over come deficiencies in some traits, while creating a new trait in the process. This new trait is summed up as the ability to take advantage of things that work to stimulate or manipulate a female into mating, even when she might otherwise be choosier.

I think it is important to see that there are no primary motivators or best features; all that matters in this system is getting copies successfully into the future.

I have always thought one fascinating thing about sexual selection is the information one can gain about a female’s mind by looking at a male. Sticking with the peacock/peahen example, the fact that a peacock has such an extravagant tail has everything to do with the female’s preference. Interesting stuff….

Do you think differentiating between "natural" and "artificial" selection is useful?

If a person is breeding dogs "artificially" doesn't it function the same as a gorillas who kills the young of another gorilla or something like that?

Humans using drugs to enhance our fitness seems ultimately natural as well, no different than symbiotic relationships throughout nature.

Basically if a human does something, it is natural, because humans are natural. We can argue benefits, but terms like artificial and natural seem unnecessary.

Is there a useful purpose that the differentiation serves?

Another one:

Is natural selection falsifiable?

Wiki definition: "Natural selection is the process where heritable traits that make it more likely for an organism to survive and successfully reproduce become more common over successive generations of a population."

Hook suggested last night that any leaps in development could falsify selection. Four thoughts:

1. Wouldn't a "leap" actually go against the basic principle of cause/effect? It's impossible apart from natural selection.

2. Speaking quantumly (not a word) wouldn't a leap be technically possible, however INCREDIBLY remote the odds are? Couldn't ProA possibly wake up tomorrow and find himself a walrus? Even if the odds are close to infinite?

3. If we do see leaps or gaps, wouldn't they be attributed to holes in our knowledge of selection rather than a hole in the theory? Missing link?

4. Can you imagine a scenario occurring, with a cause, that from hindsight could not be attributed to selection? Basically, any choice we make, the environment makes, mutations, etc. that survive will be looked back on as the product of selection, no matter what they are.

Selection is a brilliant way to describe the narrative of what has played out, but is it falsifiable?

BTW, "Darwin's Dangerous Idea" is on its way to me right now.

I should add one more time, that I don't see reasonable doubt concerning our description of life's origins. I'm just wondering if our human tendency to see purpose is at work when we look backwards on what happened.

Artificial selection is a variety of natural selection, similar to sexual selection. These are all forms of the same process, natural selection. I think the distinction is made because the adaptations that are the fruit of artificial selection are matched to mental concepts in human minds, and humans have a default tendency to view themselves as separate from the environment. This is a bias and I am happy to see POM pointing it out.

When a goal or desired outcome is specifically set forth in the mind of a breeder, we are talking about the same process but an attempt at guiding it. I think this warrants a label. What about artificial selection in terms of not just breeding, but in genetic manipulations (transferring gene splices, etc.. or even creating entirely new genes in the lab)? I still view this as the same process, but many of the gradual steps occur virtually in a brain or other type of computer. It is helpful to have a variety of labels here, but it can easily confuse someone who does not seek to understand.

Is artificial the opposite of natural? I don't think so.

Is natural selection falsifiable? The theory of evolution by natural selection is falsifiable. But what about natural selection itself? Is this a meaningful question or is it like asking if long division or arithmetic is falsifiable? Natural selection is a fact that is employed as an explainer in understanding the evolution of life.

If I understand correctly, thought 1 and 2 are in conflict. Leaps are technically possible, but they are vastly improbable. If we were to see leaps occurring at a greater than expected probability, then we could safely say that the theory of evolution by natural selection is either false, or inadequate.

The leap I was referring to last night was Haldane’s “rabbit in the Precambrian”. A hole or gap this size would certainly be a attributed as one in our knowledge of natural selection, which is the theory. Considering the amount of corroborative evidence that supports the theory, it would be likely that we mend the theory rather than throw it all out. I see it like a Copernican > Newtonian > Einsteinian revolution. But showing that evolutionary change occurs without natural selection occurring is what falsification would look like.

Thought 4, what scale are we in here? An asteroid crashing into a moon creating a crater is a scenario with cause and no selection. I suspect this is not what you are talking about. How about a belly-button or male nipples? These kinds of things are not likely to offer selective advantages but are rather side-effects of adaptations. Gould refers to these as spandrels as in the little triangular space necessarily created when one designs an arch (and Dennett sticks it to Gould in DDI, but you will have to wait and read it for yourself…). We shall continue to discuss what an adaptation is and what natural selection “sees”, but I have to cut it short for now.

I can’t decide if you would be better off reading The Selfish Gene or Darwin’s Dangerous Idea first. I read TSG first and it inspired me very much. It is what got me going on to DDI. In fact, it was TSG that got Dennett going on to write DDI. I guess you can’t lose either way. DDI is a bit longer, but you can handle it!

A couple relevant passages from Dawkins.

From The Extended Phenotype:

Quote:The biochemical controversy over neutralism is concerned with the interesting and important question of whether all gene substitutions have phenotypic effects. The adaptationism controversy is quite different. It is concerned with whether, given that we are dealing with a phenotypic effect big enough to see and ask questions about, we should assume that it is the product of natural selection. The biochemist's 'neutral mutations' are more than neutral. As far as those of us who look at gross morphology, physiology and behaviour are concerned, they are not mutations at all. It was in this spirit that Maynard Smith (1976b) wrote: "I interpret 'rate of evolution' as a rate of adaptive change. In this sense, the substitution of a neutral allele would not constitute evolution ..." If a whole-organism biologist sees a genetically determined difference among phenotypes, he already knows he cannot be dealing with neutrality in the sense of the modern controversy among biochemical geneticists.

From The Ancestor's Tale:

Quote:Contrary to my rather ludicrous reputation as an "ultra-Darwinist" (a slander I would protest more vigorously if the name sounded less of a compliment than it does), I do not think that the majority of evolutionary change at the molecular level is favoured by natural selection. On the contrary, I have always had a lot of time for the so-called neutral theory associated with the great Japanese geneticist Motoo Kimura, or its extension, the "nearly neutral" theory of his collaborator Tomoko Ohta. The real world has no interest in human tastes, of course, but as it happens I positively want such theories to be true. This is because they give us a separate, independent chronicle of evolution, unlinked to the visible features of the creatures around us., and they hold out the hope that some kind of molecular clock might really work.

Just in case the point is misunderstood, I must emphasize that the neutral theory does not in any way denigrate the importance of selection in nature. Natural selection is all-powerful with respect to those visible changes that affect survival and reproduction. Natural selection is the only explanation we know for the functional beauty and apparently "designed" complexity of living things. But if there are any changes that have no visible effect—changes that pass right under natural selection's radar—they can accumulate in the gene pool with impunity and may supply just what we need for an evolutionary clock.

Natural vs. artificial selection - "It is helpful to have a variety of labels here, but it can easily confuse someone" Totally. Anything a human does is natural. We are products of our environment changing our environment.

" Is this a meaningful question or is it like asking if long division or arithmetic is falsifiable? Natural selection is a fact that is employed as an explainer in understanding the evolution of life."

I agree. It seems that it is simply saying "the past happened to create the present".

Number 2 is kind of a toss off as any reference to quantum probabilities probably is. But it's still there in everything. definitely in conflict with 1, you're right, but I had to throw 2 out there since we talked about it last night.

Throw out Number 3 as well - fair point.

Number 1 - "leaps" A rabbit in the pre-Cambrian. Is this a meaningful example? It's like saying that the theory of time could be disproved if we wake up tomorrow and it's 1675. I suppose it might be. But everything must have a cause, so the rabbit couldn't show up without the evolution of matter and circumstance to bring it about. This sounds like natural selection. So unless we can falsify cause/effect we can't falsify natural selection.

"But showing that evolutionary change occurs without natural selection occurring is what falsification would look like. "

But as long as the basic rule of our existence - cause/ effect, all phenomena is connected - is intact - then this will always be impossible to find. Any evolution that occurs will be interpreted as natural selection. Obviously,I don't have a problem with what has happened (evolution), I'm just curious as to how much human nature plays into our labeling it as natural selection (like it's a force or has personality or a drive of its own) - it just seems so patently obvious as "fact" that I wonder why we talk about it in those terms. Something saying that "that which creates better odds for reproduction survives" seems like someone saying " the past that makes this present the most likely is what happened."

"Natural selection is all-powerful with respect to those visible changes that affect survival and reproduction."

this statement, for example, is similar to "past events are all powerful in terms of creating the present we live in"

As to superfluous nipples, perhaps they'll die out over time, or perhaps due to unforeseen circumstances, man-boobs will save the species?

---

I'm still trying to put my finger on how to understand and communicate exactly what it is that I don't get about discussing natural selection.

More thoughts ad nauseum

A - Is it possible that heritable traits that make it LESS likely for an organism to survive and successfully reproduce to flourish? Of course not. But a “successful” heritable trait is based purely on the randomness of mutation and environmental stability or change. So we can look backwards and see a pattern, but in the present moment there is not necessarily a pattern, EXCEPT the building up of random event after random event which limits present possibilities to extensions of what has already happened, and the basic law of cause and effect (all is connected).

B - There’s also the question of fitness. Some say that “survival of the fittest” is tautological. I tend to agree at this point, but I am open to argument. Some say that it’s not - certain organisms that are more fit don’t survive. It’s actually “Survival of the fit enough”. But how do we define “fit”? If we define it according to any definition except what survives then aren’t we putting needless value into a BS definition of “fit” in our minds that conforms only to a previous existing, but now irrelevant, definition of “fit”? In other words, there is no “fitness” in being stronger or faster if it doesn’t lead to survival. So the most fit survive because fitness is surely defined by its ability to help you survive.

C - Is an eyeball random? yes. If you put 100 monkeys in a room with a typewriter they will eventually produce Hamlet. But the key question here is “why is Hamlet more valuable or exceptional than random letters?” It only is because we say it is. Same with an eyeball. It’s a gradual buildup of random turn after random turn that results in something that appears meaningful to us simply because we have it.

At the risk of sounding like a broken record - I am not arguing with natural selection - I just think we tend to personalize it, give it a character or a purpose or something when it has none.

Here are two articles that address the tautology issue.

Evolution and Philosophy
A Good Tautology is Hard to Find
by John S. Wilkins

and

Darwin's Untimely Burial
by Stephen Jay Gould

I read the articles by Wilkins before I wrote anything. He didn't seem to address it well. Here's an example

“However, there is another, more sophisticated version, due mainly to Karl Popper [1976: sect. 37]. According to Popper, any situation where species exist is compatible with Darwinian explanation, because if those species were not adapted, they would not exist. That is, Popper says, we define adaptation as that which is sufficient for existence in a given environment. Therefore, since nothing is ruled out, the theory has no explanatory power, for everything is ruled in.

This is not true, as a number of critics of Popper have observed since (eg, Stamos [1996] [note 1]). Darwinian theory rules out quite a lot. It rules out the existence of inefficient organisms when more efficient organisms are about. It rules out change that is theoretically impossible (according to the laws of genetics, ontogeny, and molecular biology) to achieve in gradual and adaptive steps (see Dawkins [1996]). It rules out new species being established without ancestral species.” - John S. Wilkins

But everything that Wilkins describes is no different than survival of the fittest. Efficient vs. inefficient is the product of environment - that which survives is by definition the fittest. Ruling out "theoretically impossible" stuff is referring to basic laws - cause effect, time, new material must come out of old material, etc. And of course the last point about how a new species can't be established without an ancestral species is even more basic. It's saying that something has to have something before it.

Natural selection is a way to describe what happened, I guess. But evolution seems generally better to me. Things change, they move from here to there. Natural selection still seems that it's putting a human perspective or consciousness (however subtle) on to the process. Like there's a natural value system out there that picks certain things over others. In reality it's all a machine driven by incremental randomness - meaning that even though it's all random, each choice is still contingent on possibilities generated by previous random choices.

Looking forward to reading Dennett. Just picked it up

The term evolution can be used to describe all sorts of change. From water/wind erosion to the stages a star goes through, to the changes we observe in life. We offer explanations of these changes in terms of forces: Gravity, friction, nuclear, and so on. These forces (and accompanying theories) are sufficient to explain the evolution of sand dunes or white dwarfs, but alone they cannot account for the ratcheting complexity (or function, or purpose, or negative entropy, or whatever) of life. For this, the principle of natural selection is required.

Does the word principle do anything for you compared to force (or whatever else)?

Perhaps one reason why we talk this way about such an obvious fact is because it wasn’t always so obvious. Its obscurity was not necessarily due to the difficulty of the idea, but more so with cognitive biases and competing explanations. Natural selection is so much simpler than calculus or Euclidian geometry, but it was discovered centuries later.

The competing explanations were ones that violated our basic rule of existence, cause/effect. Most of them injected some aspect of magic or causes caused by something completely out of the system, which is the same as saying uncaused.

Don’t worry about sounding like a broken record. I think we agree nearly across the board, but we have a slight difficulty in pinning down specific meanings for certain words. I wish I could write more, but I have got to get some work done.

Get to work, Hook!


Good post. Principle is better than force. I would argue that the difference between reproduction (life, whatever) and friction or any other "force" that moves things around seems ultimately nill. I understand the need to reduce, divide and label to increase our understanding, but still. Also, isn't "negative entropy" an illusion since we're still killing off the sun's energy faster than we create greater complexity? It's weird though. Very weird.

Another interesting question - is it possible for selection to lead to a simpler organism (or part of one) or does it inevitably lead to greater complexity or keeping the status quo?

Ahhhh! I want to do anything other than what I am supposed to do!

Ultimately, the difference between any x and any y is nil. But that is not the interesting level of discussion.

Negative entropy should be encased in quotes. Life does not violate any law of thermodynamics.

There is no reason why selection cannot explore various areas of complexity in design space. There may be some limits, but it is extremely doubtful that only direction can be explored. In fact, I would bet that there is empirical evidence of this.

Back to work.

So even if eyeballs evolved “independently” (genetically speaking) along different lines and species, couldn’t it also be argued that the reason for this is that one line started developing an organ for sight - Because this was an advantage in this environment, other species’ reproduction favored the development of a sense organ for sight as well, but rather than it being an inevitable development, it was mostly in response to the beginnings of the origination of sight in one species with which it competes.

Two ideas perhaps in conflict

1. Eyesight is a random development which aids in perceiving the world. It developed along different lines, because of the advantage that it gave to organisms who live in the same environment and (more importantly) compete with one another. But if we rewound evolution and hit “go” again, perhaps there would be no sense of sight. Perhaps we would perceive “gloobiness” with our giant Gloobs and that would be the advantage which would then spread to different species because of competition.

2. Eyesight was inevitable, as sight has inherent value in perceiving reality.

Also, how can we really know if eyesight evolved totally independently? Can similar ancestry still have affected the development in different lines of species? After all, we know that “random” variations are still contingent on the past “random” variations creating variables which might be favored. Basically, even though selection is indeterminate, it has to work with what it already has and species still share common ancestry depending on how far back we go.

One example of many: Selection leading to simpler organisms (or parts)....

The blind variety of Mexican tetra, or blind cave fish.

I think that it is entirely possible that if we hit rewind/play on the evolutionary tape gloobs might evolve that allowed detection of gloobiness. But this is obviously and intentionally speculation. We have very good reasons to believe that light (electromagnetic radiation) exists in this universe independent of our ability to observe it. In other words, it was around before us and it will be around after us. (if a tree falls….sound… compression-wave…)

The instances of convergent evolution offer a sort of triangulation on the reality of electromagnetic radiation as part of the environment. The same sort of confirmation can be seen in many varieties of convergence, e.g. flight/gliding. There is plenty to argue, but from a view of convergence, it seems it is quite possible that replaying the tape might yield some familiar adaptations. Not necessarily so because of all the contingent ratcheting of frozen accidents, but possible due to observed convergence.

An easy-ish to read blog post by PZ Myers on the Evolution of vertebrate eyes. It might help explain what is meant by independent evolution. I’ll read it over this afternoon and hopefully will have more to discuss.

Very good post, thanks for the link. Myers description seems to confirm the idea that the evolution of the eye was well underway before our common ancestors split off into different lines. Fascinating. Could we have ended up with Gloobs if it was done again? Who knows. I think in all this, I am still trying to get rid of as much human bias as I can. It's ultimately impossible, but hopefully it's a good goal.

It seems a pretty safe bet that light exists. I guess we can feel the heat and see it. Funny we can't taste it.......

Actually, all the food we eat comes from light....... Light Ranch, Bud Light.....

Funny how they call it Light Beer instead of Diet Beer.