May 2008

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Volker Hetzer

I don't think food determines gender. What food /might/ determine is which sperm cell gets through the eggshell.
As for other influences, yes, there are grotesquely oversized secondary sexual characteristics in the animal world, but still, the basic mechanism is genes, mutation, competition and the fitness function. Even if "fitness" is determined by "impressiveness to female peacocks".
As someone else suggested, Darwin is a fascinating read. He arrived at the whole thing well before genes and mutations were discovered. Read his "Origin" and watch a giant think.


well, in a completely real worl setting (not in the lab) what organisms aspire to are what is useful to evolution is again based on survival.


Is DMD Dance Monkey, Dance or something else?


I think you are on the right track now. Long ago you posted, that the theory of evolution invokes you bullshit detector. Wouldn't it make much more sense, if a population could control the rate and subject of mutation of the next generations. Early giraffs operated at their maximum range when trying to get food and were still close to starving. So they started mutating spine and legs. Classical selection picked the good ones and a new species evolved...

If the mutations are not entirely random, there might be a chance, that a benefical one would occur in more than one individuum per generation. And that would make it much more likely to select and keep this modification inside the genpool.


It's not the quality of the breakfast that determines the sex.
It's the quality of the sex that determines whether you stay for breakfast.

Mike Johnston

My theory of evolution for today is that one entrant to the Kentucky Derby should be an ordinary quarter horse, and anyone who doesn't believe in evolution should be forced to bet their entire fortune on that horse.

Blue Mikey

Eric Sigurdson

"Recently I read that certain environmental conditions can increase the odds that women will give birth to boys. So we know that external conditions can influence body chemistry which in turn can influence the genetic makeup of the kid."

The only thing we know is that you read something saying that... Source please!


You must be talking about women who eat breakfast are more likely to have boys.

It's more likely that female babies give off some hormone that makes the mom nauseous in the morning or that boys make the mom more hungry with some hormone. It's very unlikely that eating more will make you have a boy.
They wrote it up to sound like that because making people think that they might be able to change the sex of their baby is way more exciting than the truth. A child's sex is determined as soon as the sperm enters the egg.
In fact this study isn't that interesting. We already have a way of knowing a baby's sex. It's called an ultrasound.

Chris H

"Recently I read that certain environmental conditions can increase the odds that women will give birth to boys. So we know that external conditions can influence body chemistry which in turn can influence the genetic makeup of the kid."

...I think that's lizards.


Speaking of testable:

#1 Why aren't there fossil remains of the all the short necked giraffes before the long necked ones came around and made the short necked ones extinct?

#2 My daughter is alot like me, despite my wife wishing she wouldn't be the entire time she was in her whomb.

I don't believe any of it.


If such was a case, then why only giraffe, even zebra, donkeys, cows and all other plant eating animals would have long necks (because secretly they all would desire longer necks!)


I think that the penis argument actually proves Scott's point. Humans have the largest members (proportionally) of any primate. The average monkey probably doesn't desire a bigger penis; he is more concerned with nuts. The average human does, over the millenia this has made a significant difference. Obviously there is still a variation. Maybe some people want it more than others.


Two comments:

1. As for the beginning of your article: You caught me unaware. I didn't know that there was any doubt whatsoever that the "most successful at reproducing pass their traits to the next generation". This empirical fact is very well established and I was really unaware of anyone defying it other than on the basis of belief. - What *is* controversial is whether this well-established fact of natural selection causes evolution. You know, whether it just keeps the species clean of runts, or if it really creates a human out of the proverbial monkey.

2. The way you pose the question, you didn't "decontaminate" it from the Darwinian stuff. If all the giraffes wish for a long neck, then they will consider the one giraffe with a long neck an attractive one. And they will all want his/her babies. If you really want to make your experiment add plausibility to your hypothesis, you will need to control (randomly, double-blindedly) how your rats mate. And by double-blind I mean, not only *you* must choose the mate randomly, but also the rat must not be able to evaluate the traits of his/her partner. (At least in rats, it's been observed that a female rat can spontaneously abort if it gets a chance to mate with a more attractive male.)

matt nicol

Stick to writing comics monkey brain.

Read Dawkins

Quit yanking our chains


Environment can influence genetic expression, but not genetic makeup. However, exposure to gamma radiation had been known to make some people turn into big green comic book heros.

Just published:
You are what your mother eats: evidence for maternal preconception diet influencing foetal sex in humans

Somebody beat me to Epigenetics.

All Hail Dogbert!


The idea actually has a lot of merit. I don't think it works on the level of chemistry, but on the level of selection by the parents who tend to favour the children that fit their aspirations best. Giraffes want to reach high places, so those offspring that have long necks are favoured by the parents, and those with short necks are neglected.


LOL Leora. My god, that was funny.

Victor Prometeo L. Frankenstein

Hi Scott,
This time I want to do the grim person with a slight tendency in believe that some conspiracy theories are true.
I want to start telling that I think You are right.
The only reason why that truth (Yours) can not be brought to the public attention, is because it leads straight to the fact that -…here You come again…- the way we think our world has a deep impact on it. From this point on, You can built Your own conspiracy theories without me telling You mines; think only of the following words: dangerous thoughts are not allowable, because of the impact they have on reality (reality = our average perception derived from the interaction with something else called: “all but me”).
Now let me continue in what it might seems a digression, but is not; …many years ago I stumbled across a pretty strange “Book” (…well, in pdf format, …and translated into my language, …and in many, many others) and even if I was educated in a certain religious way :), I read it anyway; some parts were out of my grasp because of my cultural background, but there were others, regarding the “natural world” and the way our thoughts have an impact on reality (reality in the common sense, … or in the writer sense would be more appropriate), that struck me, deeply from within. Because of that book I started wondering about true, ..its possible existence, …his possible holders, …and I started to think about how really ours thoughts are able to change reality (reality in whatever meaning); …to be honest I started to think of the stake and the Holy Inquisition too, …but that is another story.
In that book, think of it as a kind of bible if You want, I found a little part of myself, and now, with hindsight, I think in that book there was also a little part of You too, and…………
I’m very sorry, I realised that this is a very longwinded speech that might have no meaning, so let me end this comment with something I heard from D. V. Kleist about conspiracy theories, because that fits with theories in general (I quote NOT verbatim): “if You have no evidence, Your theory is a conspiracy theory, but if You have a single piece of evidence, that theory become a possibility (is not anymore an hypothesis), and the more the evidences You gather, the more Your theory approach what really happen/happened.”

Phil Bob

But you've already said many times that We're moist robots with no free will. So Even if we do have aspirations, we have no control over them. Even if your theory were true - and the penis arguments show that it is not - all you would be saying was that the random enviroment in which you were placed had an ability to affect which genes you passed on. And that's no different from evolution as it is right now.


thanks ..

thats good and If this were true, then the world would be flooded with women that have extremely large bazooms and men with extremely long ---- inseams.


I tried your rat idea in conjunction with Hiesenberg's cat experiment.

Now I have a box that may contain a cat and a bunch of extra-snouty rats. And a swarm of fruit flies.

Tomorrow when I open the box I expect I'll have a nice long-necked giraffe in it. Though I think it will die as soon as I look at it, if I remember the original experiment rightly.

Today's science lesson has been brought to you by the letter 'D', 'U', and 'H', and the number '0'.

Scott (Not Adams)

Creatures? Shouldn't they be evolvers?



We need to review the evidence. Let us use the size of the male member as the outcome, and the desire to have a big one, as the intervention.

A recent Discovery program revealed that the desire for a bigger member is pretty inbred in most males. So, using your hypophysis, what has this intervention produced over the millenia? In some enormous success, in others not so impressive results, and in some huge disappointment.

What does throw a spanner in the works though is that the less well-endowed races in this world seem to far outnumber the rest. So, although we all desire bigger penises, it seems that such desire will make us extinct.

Oh Scott, oh Scott, what have you started!?


There is no possible way that an animal can change its own DNA in a directed manner. It's as simple as that.

Hormones can affect the ways the DNA is read, but it will not affect the DNA that is passed on the children.


[Recently I read that certain environmental conditions can increase the odds that women will give birth to boys. So we know that external conditions can influence body chemistry which in turn can influence the genetic makeup of the kid.]

Wow. Talk about misleading. Environmental conditions, in this circumstance, has nothing to do with genetics. Body chemistry maybe...BUT a woman pregnant with a boy (even two cells - sperm and egg) isn't going to have it change into a girl through environmental conditions. It's going to be a boy. I think you need to read that report again.

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