Re: Coy males and insatiable females.

I have not read Roughgarden's work. I might and I may find some of it
interesting. However, I don't have to read Roughgarden's "Myth of
Sexual Selection" and "Nature's Rainbow to know Darwinian sexual
selection is not a myth. Why? Because I have read about sexual
selection and seen numerous examples of it in human nature. Mr. Menegay
states, "She is not saying that Darwin's ideas are fundamentally flawed
- she is just saying that there are a lot of fine points that have been
missed
because the outlook of the authors has been mostly male." From what Mr.
Menegay posted and reading a little about Roughgarden's views on sexual
selection, it appears she is saying sexual selection is fundamentally
flawed. I don't see her as just filling in with some new ideas
regarding the fine points. I'm including here an article by Michael T.
Ghiselin who is Chair of the Center for the History and Philosophy of
Science at the California Academy of Sciences.

As I stated, "Rather than seeing this paper try to refute Darwinian
sexual selection I wish I could find some research on gender identity
in homosexuals i.e. what makes one masculine and another feminine as
well as explanations for heterosexual couples who have no children and
those who adopt." Roughgarden states she is not interested in genetic
benefits which is the basis of sexual selection. She writes, ""We
suggest an approach that relies on the exchange of direct ecological
benefits among cooperating animals without
reference to genetic benefits." As I've indicated I'm all for such
research but it has little to do with sexual selection. Apparently,
most think (or at least Roughgarden does) this entails sexual
selection. There can be no discussion of this topic without entailing
sexual selection. That is too bad. Ultimately, the effect will be to
discredit her views regarding sexual selection, to increase the
popularity of sexual selection and to divert attention away from
research which doesn't focus on sexual selection i.e. social benefits
among cooperating animals. Perhaps that is why some individuals are
supportive of her work.

Josh states, "The fact that she's a transsexual is, to my mind,
irrelevant what matters is the soundness of her work. Yeah, except her
work in this area. According to Mr. Ghiselin of the California Academy
of Sciences "At the age of 51, Jonathan Roughgarden had himself
transformed into Joan Roughgarden, and in 2004 published a popular book
entitled Nature's Rainbow (University of California Press). It was a
work of self-justification, in which a personal agenda was overtly
discussed. Had Roughgarden simply argued that there is more to
reproductive strategies than just male combat and female choice, and
presented some reinterpretations of the data, there would have been no
reason to respond. But here we have an effort to discredit perfectly
good science." Certainly the timing of Roughgarden's sex change
operation and the subsequent publication of "Nature's Rainbow" and then
her views in papers on sexual selection hints at the possibility of a
connection. In any event, even if Roughgarden wasn't a transexual his
views on sexual selection would be equally spurious. The fact
Roughgarden is a transexual, even if such phenomenon wasn't mentioned
in the "Myth of Sexual Selection" or other writings, makes her a poster
child for her ideas and garners publicity. Has she been on Charlie Rose
yet?

Mr. Menegay writes, "I'm not sure how true this is in sexual selection
theory, but it is absolutely true in theories of hominid evolution.
Reading this group, you would think that language was invented by males
to help organize hunting groups. And that women picked up the notion
of language by listening to the mighty hunters bragging about their
exploits around the campfire." Indeed, I've mentioned more than a few
times the almost 100% dominance of males in s.b.e. I don't know why
other than man is a competing animal and all the bickering, insults,
upmannship, etc. are more reflective of the male sex (at least in
certain forms) than of the female sex.

As Mr. Ghiselin states, "In sexual selection, the selective agent that
influences each individual's reproductive success is another member
of the population-either a potential mate or a sexual rival. If the
individual gains a mating opportunity by appealing to a potential
partner or by defeating a sexual rival, the individual's reproductive
success is enhanced; if the individual fails to attract a potential
mate or is vanquished by a rival, the individual's reproductive
success is diminished. Or, "In female choice, females are courted by
males, and the females choose as mates the males that they find most
attractive."

In earlier evolutionary times it was more likely male combat would take
the form of killing other men and carrying off the women. However, male
combat today continues but it is less deadly. The principle, however,
is the same. Let's say a really attractive woman was dating several
guys. Only one individual gains a mating opportunity by defeating a
sexual rival(s). Or two men are interested in one woman but only one
gains a mating opportunity. This can take the form of male combat or
female choice. Contrary to the idea many woman initiate courtship with
a male this is rare and precipitated by "display" of the male.

I'm really quite surprised Josh and Mr. Menegay were favorable to the
idea of the "Myth of Sexual Selection" by Roughgarden. I admit I have
not read Roughgarden's work. I'm sure he is a very bright man since he
wrote an important text on population genetics and other works. On this
topic, however, I think she stepped on a big slick cow paddy.



Sexual Selection

Michael T. Ghiselin

In an article titled "The Myth of Sexual Selection" (California
Wild, Summer 2005), Joan Roughgarden, a Stanford University ecologist,
maintained that Charles Darwin had got his theory explaining some of
the differences between males and females all wrong. But it is
Roughgarden, not Darwin, who is in error.

In her opening paragraph, Roughgarden purported to describe one of
Darwin's fundamental mistakes. She told us that Darwin thought that
differences between the sexes result from a kind of natural eugenics.
In support of that claim, she presented a quotation from Darwin's
book The Descent of Man, and Selection in Relation to Sex:

He [Darwin] theorized that these male/female characteristics result
from females choosing mates who are "vigorous and well-armed . . .
just as man can improve the breed of his game-cocks by the selection of
those birds which are victorious in the ***-pit."

In fact, this is a bogus quotation. Roughgarden evidently contrived it
by joining two phrases that appear on different pages and on different
topics in the second edition of The Descent of Man. The words
"vigorous and well-armed," lying to the left of Roughgarden's
ellipsis periods, are followed by the words "and in other respects
more attractive." They are from a passage that explains how the
sexual characteristics in question can evolve even in monogamous
species. The rest of the material quoted comes from a passage three
pages earlier, and discusses the perpetuation of traits that enable
some males to defeat other males in contests for mating opportunities.
The original sentence in its entirety reads: "Just as man can improve
the breed of his game-cocks by the selection of those birds which are
victorious in the ***-pit, so it appears that the strongest and most
vigorous males, or those provided with the best weapons, have prevailed
under nature and led to the improvement of the natural breed or
species."

Roughgarden's use of a fake quotation in the very first paragraph was
appropriate, because the whole article was grossly misleading, both
with respect to what it said and what it failed to say. Because
Roughgarden's article misrepresented Darwin's views and confused
them with those of other authors, I shall review some of the things
that Darwin actually did say and some of the concepts he actually put
forth. On that basis I will then explain why Roughgarden's claim that
Darwin's theory is a myth is out of line with well-established
scientific facts.

Darwin's book On the Origin of Species by Means of Natural Selection,
or the Preservation of Favoured Races in the Struggle for Life was
published in 1859. It provided compelling evidence that organic
evolution has indeed taken place, presented natural selection as a
mechanism that can cause evolution to occur, and made Darwin famous as
the founder of modern evolutionary biology.

When students in middle school and high school science courses are
taught about evolution, they typically learn about natural selection,
including the roles of mutation, variation, and the struggle for
existence. They may not realize, however, that Darwin also elucidated
two other evolutionary mechanisms: artificial selection and sexual
selection. Each of these modes of selection played its own role in
Darwin's thinking about evolution.

Natural selection, artificial selection, and sexual selection are all
variations on a common theme, and all work in the same basic way. They
involve some members of a population being particularly successful in
producing offspring. In the long run, as each generation is succeeded
by another, the characteristics of these more successful individuals
become more frequent within the population. What distinguishes each
mode of selection from the others is the agent that does the selecting.

In artificial selection, the selective agent is a human-a
breeder-who picks an individual out of a population of domesticated
animals or plants, then uses that individual for breeding purposes. The
human thus ensures that the selected individual will enjoy greater
reproductive success than others. This process of artificial selection,
commonly called selective breeding, has given rise to highly modified
varieties of cattle, chickens, pigeons, dogs, tomatoes, apples, grasses
(such as wheat, maize, and barley) and countless other domesticated
animals and plants. Artificial selection was fundamental to Darwin's
thinking about evolution because it showed that selection has in fact
transformed real populations of organisms and even enabled a single
ancestral population to give rise to multiple descendant populations
that differ from each other and from the ancestral stock.

In natural selection, there is no human selective agent. The
environment does the selecting. The members of a population compete to
extract resources from their environment and to convert those resources
into offspring. Some individuals are more successful at doing that than
others, and contribute more offspring to the next generation. As a
result, their characteristics become more common. Natural selection was
crucial in Darwin's thinking because it provided a plausible
explanation for adaptation, abolishing any need for explanations that
invoked the supernatural.

In sexual selection, the selective agent that influences each
individual's reproductive success is another member of the
population-either a potential mate or a sexual rival. If the
individual gains a mating opportunity by appealing to a potential
partner or by defeating a sexual rival, the individual's reproductive
success is enhanced; if the individual fails to attract a potential
mate or is vanquished by a rival, the individual's reproductive
success is diminished.

The existence of not one, but three, modes of selection, provided
Darwin with a broader theory than natural selection alone. They
generated different predictions, and, taken together, strengthened his
case for selection as a mechanism. Sexual selection was particularly
important, because it showed how purely reproductive competition could
produce features that are not adaptations that further survival or
somehow benefit the species.

Conceptually, sexual selection is more similar to artificial selection
than to natural selection. Sexual selection occurs in several forms,
two of which are particularly relevant to the present discussion:
female choice and male combat.

In female choice, females are courted by males, and the females choose
as mates the males that they find most attractive. Darwin suggested
that the females possess an aesthetic taste, akin to our own but less
refined, and that this aesthetic sense governs the choices that the
females make.

To the extent that female choice is acknowledged in introductory
biology textbooks, it typically is described as the mechanism that
accounts for the evolution of gaudy coloration and exaggerated plumage
in certain bird species. If hens are attracted to, and mate
preferentially with, cocks that exhibit bright colors and elaborate
tails, then the males that possess these features will be more
successful in acquiring opportunities to sire offspring. Conversely,
males that lack these features will fare poorly in the mating game.
Over generations of such selection by the females, the males will have
increasingly bright colors and elaborate tails. Furthermore, continued
selection by the process can go to an extreme-witness the pea***.
(Darwin compared the showy nuptial plumage of wild birds to the showy
plumage that breeders had established, by artificial selection, in many
varieties of ornamental poultry.)

In male combat, Darwin's second form of sexual selection, males fight
other males, and the winners gain a monopoly over the females. The
females don't make choices. The males fight among themselves, often
with weapons such as horns, antlers, hooves, or teeth, and the
successful males sire all or most of the offspring that constitute the
next generation. The fighting can be quite spectacular. We have all
seen films showing male combat in deer, bighorn sheep, and other
animals.
Roughgarden presented a pair of fighting bull elk as an example of
something thought to be selected by the females because of its putative
eugenical effect. Although some later authors attempted to put that
sort of spin on it, Darwin treated it as an effort to monopolize the
opportunity to mate pure and simple. The females are not in a good
position to make that kind of choice even if it is to their advantage.
Roughgarden has handed us a travesty of sexual selection theory and
used it as a straw-man.

The notion that a pea***'s tail is chosen as a sign of genetical
superiority has been maintained by some authors, but Darwin did not
know about genes, and he did not explain female choice in terms of
eugenics either. His explanation was that the stronger the stimulus,
the more attractive it is to the females. Recent studies have supported
that view, by showing that the preference for the stimuli was already
present before the exaggerated ornaments evolved. Both explanations
might be true, however, and it is difficult to decide between them.

Sexual selection, whether by female choice or by male combat, is
conceptually distinct from natural selection, but each mode's
relative contribution is hard to evaluate. Consider a case involving
female choice. As Darwin recognized, a female may find a particular
male attractive for some reason other than his bright colors, his
jaunty crest, or his big tail; she may choose him because he appears to
be healthy and highly vigorous. This would make him a fortunate choice
if he is going to have to contribute in some way to the welfare of the
pair's offspring-say, by protecting them from predators or by
obtaining food for them. But a male's good health and great vigor are
also advantageous to him as he tries to cope with his environment and
to survive on a daily basis. In other words, his good health and great
vigor affect his capacity to meet the requirements of natural
selection, regardless of whether they impress any females. Thus, even
if she selects a mate because he is vigorous, that is natural, not
sexual, selection.

To establish the fact that sexual selection does in fact occur, we need
to be able to separate its effects from those of natural selection.
Sometimes we can do this, because there are some species in which we
can see "pure" sexual selection-sexual selection that operates
alone and doesn't overlap with natural selection. We can then compare
that species with other, related species, in which sexual selection
does not occur, or at least is less intense.

One species that offers us an opportunity to see sexual selection in
its pure form is the northern elephant seal (Mirounga angustirostris).
During their breeding season, elephant seals crowd themselves into
rookeries where the females give birth to offspring that were conceived
a year earlier, during the previous breeding season, while the males
fight with each other to monopolize the females, mate with them, and
sire the offspring that will be born a year hence. The females nurse
the young seals that they have just delivered, but the males do not
care for the young at all, nor do the males do any courting. The
biggest males devote themselves entirely to fighting for territories,
to controlling females, and to defending their territories and their
females from other big males.

Under these conditions, the males experience intense, purely sexual
selection by combat. They don't have to get food for themselves as
they don't eat during the breeding season, they don't have to
defend offspring, and they don't have to cope with predators (while
they are on land, they are beyond the reach of any predators that are
big enough and strong enough to threaten them).

Now look at the effects of this sexual selection. The males may weigh
as much as 5,000 pounds while the females typically weigh less than
2,000. This extreme difference in size between males and females is due
entirely to sexual selection by male combat, and it is there for all of
us to see, even if Roughgarden imagines that sexual selection is merely
a "myth."

A similar pattern, with the males much larger than females, occurs in
other pinniped species. Sea lions display a breeding regime similar to
that of the elephant seal, complete with tightly packed rookeries and
continual fighting among the males for territories and females. We do
not find any comparable dimorphism in pinnipeds that do not display
such a regime. In the Hawaiian monk seal, for example, males and
females are of approximately equal size. It is this kind of comparison
that provides the compelling evidence in favor of Darwin's theory.

My own interest in sexual selection arose many years ago while working
on my book The Triumph of the Darwinian Method (University of
California Press, 1969). A review of the literature convinced me that
Darwin's theory of sexual selection had not been properly understood
and had languished in neglect, and that many reproductive phenomena
needed to be reinvestigated. My understanding of Darwin's thinking
allowed me to solve the puzzle of sequential hermaphroditism.

An hermaphrodite is an organism that can function both as a male and as
a female, either at the same time or at different times. An organism
that functions in both roles at the same time is called a simultaneous
hermaphrodite. An organism that functions first as a member of one sex
and later as a member of the other sex is called a sequential
hermaphrodite.

There are two kinds of sequential hermaphroditism. In protandrous
hermaphroditism, an individual spends a part of its life as a male and
then becomes a female. A protogynous hermaphrodite is an individual
that spends a part of its life as a female and then becomes a male.

The reproductive regimes of coral reef fishes often revolve around
protogynous hermaphroditism. Here is a simplified description of one
such regime that occurs in certain species of wrasses. These animals
begin their reproductive lives by functioning only as females, though
they possess both male and female sex organs. The females living in any
particular place constitute a harem that is controlled and defended by
one male, who is typically far larger than the females. The females in
the harem form a hierarchy, with one female-usually the
largest-dominating all the others. This arrangement remains stable
until the reigning male is devoured by a predator or is otherwise
removed from the scene. When that happens, the dominant female quickly
changes sex and becomes the new reigning male.

In certain other species of wrasse, some of the females-as they
become older and bigger-turn into males and go roaming in search of a
territory in which they can assume the role of reigning male.

To explain life histories such as these, I proposed what I called the
size-advantage model of sequential hermaphroditism: "If a small
animal (or a young one) can reproduce more effectively as a member of
one sex, while a large animal (or an older one) can reproduce more
easily as a member of the other sex, then it becomes advantageous for
an individual to switch gender as it grows and ages."

A protogynous wrasse reproduces as a female while small and young
because this is the only way in which this individual can reproduce at
all: though she carries the sexual equipment of both sexes, she is too
small to claim and hold the position of a reigning male. But when she
grows large enough to function as a reigning male, she can greatly
increase her reproductive output by doing exactly that. Consider: If
she continues to function as a female, she will continue to have only
one mating partner. But if she can herself become a reigning male, she
(turned he) will win a big reproductive payoff.

I proposed the size-advantage model in a paper published in 1969, and I
expanded on it in my book The Economy of Nature and the Evolution of
Sex (University of California Press, 1974). The neglect of sexual
selection came to an abrupt end, and the size advantage model was soon
confirmed and extended. The theory bore unexpected fruit when applied
to a wide range of organisms, including flowering plants. It even
explains such phenomena as the little males in some gastropods that
scramble to find a female, then become females themselves. Yet
Roughgarden asserts in her article, "After 130 years, sexual
selection is still not confirmed, and I suggest it never will be." In
fact it has been confirmed time and time again.

In general, males specialize in getting the sexes together, whereas the
females specialize in provisioning the next generation with resources.
Sometimes this leads to males that are larger than females, but this is
exceptional, and generally happens where there is sexual selection by
male combat. Where the mode of competition between males is a matter of
getting to the females first, the males tend to be smaller, as happens
in some barnacles, certain deep sea fishes and quite a range of other
animals. Indeed, male/female dimorphism of eggs and sperm, with the
latter being much smaller, is perhaps a better way to conceptualize the
differences between males and females than what we see in species with
large and combative males. Such facts quite reasonably can be used to
disabuse us of our prejudices and misconceptions. But this raises a
second problem with Roughgarden's article: it gives no indication of
the author's ulterior motivations for writing it.

At the age of 51, Jonathan Roughgarden had himself transformed into
Joan Roughgarden, and in 2004 published a popular book entitled
Nature's Rainbow (University of California Press). It was a work of
self-justification, in which a personal agenda was overtly discussed.
Had Roughgarden simply argued that there is more to reproductive
strategies than just male combat and female choice, and presented some
reinterpretations of the data, there would have been no reason to
respond. But here we have an effort to discredit perfectly good
science. To suggest, on the grounds that it may not explain everything,
that sexual selection or any other scientific theory is wrong, is an
offense against elementary logic and common sense. In claiming that
sexual selection is false, Roughgarden has created her own mythology.

Whether selection theory in general or sexual selection theory in
particular might be improved upon is not an issue. We have a much
better understanding of sexual selection now than we did 35 years ago
for the very reason that scientists have been actively questioning
received views and proposing alternatives. Honest seekers after truth
do not want to suppress controversy. But they also do not want to see
the issues misrepresented.


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Michael T. Ghiselin is Chair of the Center for the History and
Philosophy of Science at the California Academy of Sciences.


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