Tuesday, June 26, 2012

Do Men Cheat More Than Women?

It's not often that the BBCworldnews runs an article that disappoints me. Unfortunately the other day it did, one which was entitled "More or Less: The Maths of Infidelity." The thrust of the article was that even though it takes two to tango an American study found that more men than women admitted to having affairs ergo: men cheat more than women. Most won't see this as a profound or new conclusion since many seem to intuitively believe this anyways.

 Rubbish. My major problem with this view is that it suggests that cheating is innately gender specific, i.e., that males are simply hardwired to cheat more than females. Usually, evolution is then brought into play to account for why males supposedly have more of a propensity to cheat, namely, that since they have a more compelling desire to spread their genes they will have more of an inclination to seek out a multitude of mates. But this ignores the fact that female promiscuity is also prominent in the animal kingdom, especially among our closest living ancestors the great apes. (See for example the Bonobo.)

Curiously though the article didn't try to use evolutionary psychology to explain why men supposedly cheat more than women. Instead, it just threw out some abstract reasons: because men get lonely, because men get bored, because men aren't being sexually fulfilled, etc. The absurdity of these reasons should be clear: they apply equally as well to why some women might cheat also. Additionally, this article only cites one study that depends on the questionee answering truthfully. Perhaps then one could just as easily draw the conclusion from this study that women are simply better liars than men. In short, this article is in no way scientifically sound.

But why do so many people take it as a given that men cheat more than women? Well, because at one time this was certainly probably true, at least up until about 50 years ago. Now, however, there has been a major shift in women's roles in the last several decades that among other things has seen them take up a large portion of the workforce. In short women are not in the home all of the time anymore and so have more opportunities to, well, cheat if they so choose. In other words what I'm trying to get at is that cheating is something more contextual or situational and historically most women have had very confined roles, usually to the household. To put this in terms of the nature vs nurture debate I think cheating is not something innate within males to do (the nature position) but rather is something more environmentally produced (the nurture position) and thus can affect equally both males and females.

At any rate this is a fruitless question to ask since there's no way it can ever be answered with any kind of scientific probability. Still, I'm throwing the bullshit flag on this misguided but widely held belief that men are more prone to cheat than women. Hogswallow.

Wednesday, June 6, 2012

CSI Cretaceous Part 2

There is a major problem with the asteroid extinction hypothesis of the dinosaurs that fails to convince Bakker of its soundness. He notes that the fossil record when looked at more closely actually indicates something other than a sudden disappearance of dinosaurs. In fact, the fossil record shows a period of gradual decline in the evenness of dinosaur species beginning early in the Late Cretaceous. By "evenness" Bakker is referring to the ratio of one species to another. In most types of healthy ecosystems the varying species should be approximately equal to one another. It's once you have a disproportionate amount of one or two species over others that the ecosystem begins to degrade. Bakker found in the dinosaurs of the Lance faunas examples of a loss of evenness in the variety of dinosaur species some two million years before the end of the Cretaceous. For example, "the genus Triceratops made up 70 to 80 percent of the finds of large dinosaurs." (437)  In other words, several millions of years prior to the end of the Cretaceous there were many dinosaur species already in major decline, some extinct even. Thus, Bakker says, an asteroid impact occurring at the end of the Cretaceous can not fully explain the extinction of most dinosaurs. At best it might have served as "the coup de grace to a dying ecosystem already suffering from massive problems." ( 439)

Bakker's own solution has two interrelated components. For the first part of his explanation Bakker adopts what is known as the "drain-mix-and-cool theory of extinction for the ocean" or for short the "shallow seas theory." (439). This theory states that abnormally warm periods on earth cause shallow seas on land to drain off the continents into the ocean causing, paradoxically, an overall cooling trend for the planet. Bakker on the consequences of these changes for the ecosystem:

"The best answer for the extinction of the great sea animals is that their favorite haunts disappeared when the warm, shallow seas drained off the continents. And the best answer for the extinction of the open-water, deep sea creatures is that surface water becomes colder and more thoroughly mixed with deep water when the shallow seas drain off." (439)

 According to Bakker these changes are well documented. He asserts that climatologists have in fact determined that during the middle Cretaceous there were many shallow seas on the present day continents. (For example, present day North America during this period had a huge in land sea extending from the arctic down through central America. See picture to the right.) Moreover, they have also noted that towards the latter portion of the Cretaceous these shallow seas were in fact rapidly disappearing. So then we have a reasonable explanation for the extinction of some dinosaur species via documented climate changes. However, as Bakker notes this explanation is incomplete since the resulting overall cooling trend of the planet would likely not have killed off the big land dinosaurs that were not already in some fashion dependent on the inland seas.

Thus, the second component to Bakker's explanation:

"Let us observe the historical sequence that unfolds on the land during the mass extinctions. Shallow seas drain off, so that land areas once underwater become dry and regions that had been separated from each other become connected by land bridges or island chains. At the same time, mountain-building forces weaken so that there are fewer barriers dividing the terrestrial regions...But the net result is a more homogenized ecosystem where species can pass more easily from one end of a continent to another, and from one continent to another. Such easy intercontinental exchange can be found precisely at the end of the Cretaceous. Until late in the Cretaceous, Mongolia had supported quite a different fauna from that of North America. There were many advanced mammals and protoceratopsid dinosaurs in the Central Asiatic Highlands not found in Alberta, Montana, and Wyoming. But very late in the last epoch of the Cretaceous Period, the Asiatic mammals and dinosaurs began appearing in North America...Could such interchanges over the continents cause extinction?" (441-42)

Bakker answers in the affirmative noting that "one of the unshakable tenets of animal geography is that the most extreme consequences are possible when foreign species move into a new region." (442) Every species carries its own set of parasites and disease organisms that it has over time adapted to. But when these species are introduced into an area with other species that have never had any contact with such diseases and parasites the result is often the decimation of the latter. History offers many examples of this from the Black Plague (introduced from Asia to Europe), to the destruction wrought by Rinderpest (an Asian cattle disease introduced into Africa by Lord Kitchner), to the settling of Old World peoples with Old World diseases (such as smallpox) into the New World causing the devastation of the vast majority of New World populations, and many more. But the dangers of interspecies mixing doesn't just come from unfamiliar germs and bacteria. The introduction of larger animals into a new ecosystem can also wreak havoc as the Australians learned when rabbits, a relatively minor nuisance in Europe, were first brought to the land down under where they now have become a major pest doing much ecological harm to the Outback.

Likewise then with the dinosaurs concludes Bakker:

"The Late Cretaceous world contained all the prerequisites for this kind of disaster. The shallow oceans drained off and a series of extinctions ran through the saltwater world. A monumental immigration of Asian dinosaurs streamed into North America, while an equally grand migration of North American fauna moved into Asia. In ever region touched by this global intermixture, disasters large and small would occur. A foreign predator might suddenly thrive unchecked, slaughtering virtually defenseless prey as its populations multiplied beyond anything possible in its home habitat. But then the predator might suddenly disappear, victim of a disease for which it had no immunity. As species intermixed from all corners of the globe, the result could only have been global biogeographical chaos." (443)

(Note: this intermixing depends on the majority of dinosaurs being warm blooded; cold blooded animals would be unable to travel long distances.)

So to recap, Bakker's position on the extinction of most of the dinosaurs runs as follows:

1.) The fossil record indicates that millions of years before the end of the Cretaceous many dinosaurs species were declining, a few actually becoming extinct. An asteroid impact at the end of the Cretaceous cannot fully account for this data.

2.) In the latter part of the Cretaceous the shallow seas began to drain off the continents causing the extinction of major sea animals as well as opening up massive new areas of land travel.

3.) The resulted intermixing of new species of dinosaurs introduced various agents of extinction such as new germs, parasites, bacteria, etc, and other ecological changes that eventually killed off many of the dinosaurs.

4.) The remaining few species of dinosaurs (excepting a few) may have finally been killed by the impact of a heavenly body of some kind at the end of the Cretaceous.

I for one find Bakker's thesis very persuasive. However, while most of what Bakker put forward in this book has since become part of mainstream paleontology, his views on dinosaur extinction has, to my knowledge at least, yet to be wholly accepted. I suspect this is because Bakker's explanation is so mundane. Most dinosaurs died out because they mixed with other, previously, isolated species of dinosaurs?!  In other words, Bakker's explanation fails to dazzle us like the traditional view that most of the dinosaurs were killed off in one fell swoop by a gigantic asteroid. We prefer big, amazing explanations for things, especially mysteries. And for this reason I doubt many people will be convinced that most of the dinosaurs actually died off in a rather unexciting manner. Yet sometimes the truth, whether we like it or not, can be rather, well, banal.