PhDP

What if the mutation rate is once per million years?

No. Frakking. Way.

It HAS to have happened several times. Look at the equation, the probability of fixation of a neutral mutation is 1/2N. It's very low.

The mutation rate for humans is about 200 mutations/genome/generations, and there are several ways to break a gene, from simple mutations like a point mutation to catastrophic mutations like a frameshift. More to the point, since it has lost its function, the gene that was responsible for the synthesis of vitamin C has accumulated several mutations;

Biochimica et Biophysica Acta 1472:408-411.

About raising children;

From a purely theoretical POV, it's safe to say that homosexuality is not a problem. Empirical evidences seem to go in the same direction. I read an article about this some time ago. There were few differences between kids raised by heterosexuals v. kids raised by homosexuals parents, except one thing, kids raised by homosexuals were more tolerant and less aggressive (i.e: gutless Democrat cowards).

I could try to find the reference if someone is interested, I know I found it by looking for info about a vaccine (probably the MMR vaccine).

Anyway, my semi-relevant point was only that adopting is not a right, but even if it's not I see no rationale to refuse this to homosexuals.

...just a semi-irrelevant note. Of course I support gay marriages, I think I've already 'defended' homosexuals on a certain number of occasions. But adoption is not a right. The kids should be given to the best possible parents, and any justifiable discriminations is perfectly normal. That being said (and it's why this note is pretty irrelevant), we have all the reasons in the world to believe that homosexuals are as apt as heterosexuals when it comes to children. It's simply not true that kids need a dad and a mom, they need people to satisfy their needs.

Skeptic lance - I don't know much about the energetic costs associated with Vit. c manufacture, but could this have conferred a slight advantage to non-vit synthesizing individuals, if one member randomly lost it?

Very often, slight advantages mean nothing for evolution. For very small organism with ridiculously large population size (i.e.: bacteria), I could buy the energetic costs argument.

But for large organisms like us... no. I can't see how a tiny detail like this could lead to a significiant advantage.

I just want to answer to something SkepticLance said about vitamin C, first because he made a mistakes, but also because it leads to a simple explanation of the molecular clock (the idea that we can use DNA to date events).

The other thing that relates to loss of vitamin C manufacturing ability' date=' in addition to the fruit diet mentioned by ecol, is a very low population number. The loss came about because of a mutation in a key gene, that spread to all humans. That spread would not have come as a result of natural selection, since there was no selective advantage. It would have come as a result of genetic drift, which is something that does NOT happen in large populations.

 

Thus, the loss happened at a time when our forebears were very low in population size. We can also conclude that a similar event CANNOT happen today, with 6.5 billion people interbreeding.[/quote']

 

Effective population size is fundamental to, well, pretty much everything in population genetics. But in this case, it doesn't matter.

 

For diploids, the probability of fixation 'f' of a new mutant with selection coefficient 's' and population size 'N' is given by;

 

[math]

f(s) = \frac{2s}{1-e^{-4Ns}}

[/math]

 

(We get this equation from the diffusion approx.)

 

Now, losing our capacity to produce vitamin C doesn't matter if we already get this vitamin in our diet, so a mutation that would destroy our capacity to produce vitamin C will have a selection coefficient of 0 (in short, it's neutral). With s = 0 and l'Hôpital's rule we find that;

 

[math]

f(0) = \frac{d(2s)/ds}{d\left(1-e^{-4Ns}\right)/ds} =

\frac{2}{4Ne^{-4Ns}}=\frac{1}{2N}

[/math]

 

If the mutation rate for this gene is [math]\mu[/math], then the total number of mutations appearing in a population is simply;

 

[math]

\mu 2N

[/math]

 

...because a mutation can appear in every single individual. High population = more mutations. As a last step, we combine this with the probability of fixation to get the rate of substitution 'k', that is, how many mutants will reach fixation in a generation;

 

[math]

k = \mu 2N \times P(s)

[/math]

 

With this equation we can see that the rate of substitution depend largely on the effective population size. However, in the neutral case;

 

[math]

k = \mu 2N \times P(0) = \mu 2N\frac{1}{2N} = \mu

[/math]

 

This is simple, but it's also an extraordinary result; the rate of substitution of neutral mutations is NOT affected by time or population size, it depends only on the mutation rate...

 

Molecular clock

 

If we can find a "neutral region" shared by two species, that is, a region of DNA where mutations are neutral, then, only by looking at how many substitutions occured, we can estimate the time of divergence of these two species.

Rice, S.H. 2004. Evolutionary Theory.

A short book ideal for someone interested in the fundamental principles of the theory evolution and the basic mathematical structure of the theory.

The first chapters cover population genetics; selection, mutations, drift, and how to combine these mechanisms with diffusion theory.

The other half of the book covers the evolution of the phenotype; quantitative genetics, game theory, multilevel selection, evo-devo.

The maths required; not much, basic calculus, some linear algebra.

If by hard you mean hard to understand, then it's certainly (from the hardest to the easiest);

mathematics / physics / (chemistry & biology) / [insert any social science here]

However, if you have a good math intuition, then it's the exact opposite. I bet many scientists here would do better in a physics course than in an 'easy' area like history.

Well physics is based up on mathematical rules and principles form which you should be able to derive what you want to know (in principle). Chemistry, is also a bit like that, but full of names you need to remember and then Biology is just remembering lots of facts and names.

It's both very true and not accurate at all. First of all, biology is just so vast, it's hard to make any generalization. Also, I think it's important to make a distinction between how biology is taught, and biology as a science. Too often, it's true, biology is reduced to memorizing details about morphology, names, molecules, et cetera...

But it's not always the case (and it should never be the case). A good example is evolution. Evolution was founded on a much stronger basis than any field of physics; mendelian genetics, and our understanding of evolution was derived from these simple basic rules to create a coherent mathematical structure.

...in short; 'weak atheism' = no burden because they don't accept as true the proposition "god doesn't exist" (your #2). 'strong atheism' = burden because they make the claim "god doesn't exist" (#2a & #2b).

But again, most of the time when we say something doesn't exist, we're saying so because not enough evidences is given, not because we're actually making the opposite claim.

Scientists (all of whom were theists) showed it to be false.

That again ?

The burden of proof is on theists and strong atheists - both.

I agree, and Mr Skeptic said about the same thing, but is there even one of these mythical 'strong' atheists here ?

Mr Skeptic,

I like your examples, but I respectfully disagree, I think your interpretation is overly literal. Most of the time when we say "I don't believe X exist", it means "I think the existence of X is highly improbable". By definition, only strong atheists accept as true the notion that "God doesn't exist". Same thing goes for Bigfoot, lots of scientists have said they don't believe Bigfoot exist, but they don't actually accept as true the proposition; "Bigfoot doesn't exist", they simply see no reasons to believe in the existence of such a creature (well, to be fair, we do have some evidences that he doesn't exist, but it's another story).

Have you ever said you don't believe in santa claus or in the tooth fairy ? I'm pretty sure you did, and I'm also quite sure that what you really meant was; we have absolutely no reasons to believe in the existence of those entities, so, the probability that they actually exist is very low. You espouse 'weak' "asantaclausist" and "atoothfairyist", until somebody providence evidences, you don't need to do anything. It's the same thing for any theory, any hypothesis... It's no different for god.

They don't

It depends... In Québec, I think a civil union is pretty much the same thing as a marriage (anyway, both civil unions and marriage are available to homosexuals)

That would be most atheists. However, since they almost always lump themselves with strong atheists, this creates some confusion. A better claim is that god's existence is not necessary to explain the physical universe.

I agree. But most atheists are 'weak atheists'. AFAIK, 'strong atheism' is quite rare. I don't believe in god just as I don't believe in the tooth fairy. I accept that I can't prove the inexistence of these entities but I refuse the burden of the proof.

And why should they? Strong Atheists won't accept the burden of proof either, and neither side has shown any proof that the other side is wrong. Sure, a few individuals on both sides have made attempts to prove their side, but those are few and far between.

'Strong atheists' should accept at least some of the burden of the proof.

Usually, whoever makes the initial claim that the other side is wrong in a particular argument is expected to provide some evidence for that position, since they are the ones making a claim.

I agree, but obviously, atheism exist because theists have proposed the existence of some supernatural deity. How could we have made the initial claim ?

And if we have to prove god's inexistence, if we have to share the burden of the proof, it means we also have to prove the inexistence of all the other supernatural entities. Why is god a special case ? Why theists won't accept to play by the rule ?

Atheism, to be atheism, must have at least one positive statement of faith: natural = without deity.

It's not a statement of faith, it's parsimony. I could say that Belenos is the force behind mutations, and the lack of belief in Belenos' presence is a faith because it implies that; mutations = without Belenos. Same thing for god, why would we believe in the existence of god in the universe, it explains nothing.

We can't even say it explains religious beliefs/experiences, as people from different regions of the world believe in different things. If you were born in Japan, you would probably bash the concept of god and believe in Kami.

Please point to the peer-reviewed scientific paper that shows deity is "imaginary".

Again, it's parsimony, we have absolutely no reason to believe in the existence of an anthropomorphic god. Why would science produce peer-reviewed scientific papers about a hypothesis based on no reliable evidences ? There's no scientific paper that proves shamanism to be bogus, AFAIK.

So, it is the onus of atheism to falsify the existence of deity.

We have a lot of work then, because there's an awful lot of mythological creatures out there, and most of us don't believe in them so we need to provide evidences. Let's start with "A" then; Aed, Amaterasu, Ajatar, Alseid....

Most fairy tales can't, and won't, be falsified. Your argument is a stawman, atheists don't say; god doesn't exist, they say; god's existence is highly improbable ('weak atheism').

I find this situation quite annoying, it's nearly impossible to have a civil discussion about the concept of God because theists won't accept the burden of the proof (which is probably a good strategy, when you think about it). How can I prove the inexistence of the christian god ? I can't, and christians can't prove the inexistence of the gods from other mythologies, they can't prove the inexistence of Kami and spirits, et cetera...

The connection also comes because many atheists -- like creationists -- refuse to admit that their faith is a faith. They want science to "prove" their faith. Therefore they misrepresent science and reasoning as having "shown" that deity does not exist.

 

The "connection" is that we have a war between two faiths -- atheism and theism -- and the battleground is science.

Actually, it's not true at all. I think science has made the belief in the supernatural unnecessary, but I certainly don't believe science has shown that god doesn't exist. It's a very important distinction, we can reject a hypothesis because we don't need it anymore, even if we can't disprove it.

"None of the Above".

Edwards | Paul | Kucinich = Impossible.

Clinton = Possible, but unlikely.

What about more credibles candidates ?... Richardson, Webb...

ok, I'm getting tired of this, as soon as I have a little time I'm going to write a small article to explain that, if there's no junk in our DNA, then the theory of evolution is wrong.

YT,

I fail to see why my life would be dull simply because I'm not interested in the local mythologies.

fact is (as evidenced in myself) there IS no connection!

In fact, there is a very strong connection; both makes claims about the universe, based on a different approach.

this is the majority reason why I wanted the P&R section closed too, if we have that we should have one for Snowboarding and flower arranging also, as well as any Other nonsensical random stuff anyone cares to think of.

You think there's no link, but the fact that the P&R section was so active and full of references to science is living proof that many people here don't share your view.

I think science is all about reducing the need for faith, but not about eliminating it. If my hypothesis is that, when I die, my consciousness can exist on its own if I can keep my sanity (which may be hard without all the familiar sensational input I lost when my body died), there are few ways I can test it without actually dying. If I further believe that a collective consciousness might exist and that I could be a part of it if I'm deemed worthy (no one wants to share consciousness with a mass murderer, after all), then it goes a long way towards explaining why so many people mount whole religions around the concept of moral worthiness. And lastly, if my hypothesis is that a being of pure consciousness might have access to higher dimensions predicted in other theories, then why is my idea of religion so at odds with science? I'm just waiting, after all, for testability to draw some conclusions from my predictions.

IMHO, it's faith as its worst. You believe in an universe tailored for your needs, then wait for science to provide evidences. It's exactly what many creationists are doing; they wait to science to confirm their beliefs, even if they have all the reasons in the world to believe that science is doing in the exact opposite direction (the same thing could be said for life after death). Your idea of a religion is at odds with science for many reasons. #1 because you can't provide any evidences or rationale for your predictions. #2 because it does conflict with many of our modern theories, after all, asking consciousness to exist outside the body is like asking a broken computer to calculate. And worst of all, #3; because you ask science to get to a particular result.

Science should be driven by curiosity, by the profound and honest desire to understand how the universe work, even though we might not always like what we see, even when it doesn't serve our personal interests. Certainly, it should note be done to justify our own prejudices.

Beside, evolutionary biology is mostly associated with ecology.

Isn't the subsection "big" enough to warrant it's own category? It's 11 pages long now...

It's 25 pages long, vs. 12 for Genetics

Wow, this thread is refreshing. What would happen if all of math and its uses were only done in statistics, what do you think human understanding would look like? I mean could you model gravity with just stats?

You can (in fact, must) use statistics to test hypotheses, and you can use statistical inductions to uncover relationships.

But you can't have a theory of gravity based solely on statistics. Gravity does not depend on probability (it's not a stochastic procress), at least, not according to the theory of relativity... As such, there's no point to model gravity with just stats. And anyway, even statistical physics (used, for example, to study thermodynamics) depend on much more than just statistics, it relies on algebra, calculus, and probability theory (which is an important foundation of statistics, but not considered within the field of statistics).

There was a significant apple scare in the 1970's -- a medical study linked cancer and apples. As you can image, for a time the sales of apples completely plummeted. But, it was all a coincidence.

We live in a society fundamentally hostile to the concept of 'coicidence'. You're the lone survivors of a plane crash ? It's fate ! or god ! or destiny (of course, the other ones were just bad people)...

I can't do mathematics in my head.

 

That's why I never decided to pursue a career in theoretical physics.

What ?

At the university, I've nearly lost my ability to do maths in my head. I'm so concentrated on the concepts that I open Matlab for simple calculations.

Laypeople tend to overestimate our understanding of the universe, mostly because, in school, they concentrate on what we know and often in a very rigid matter. Also, science popularizers also tend to focus on the problems we solved.

Well, there are many reasons....

#1. As a society, we need people with skills in maths & science. Where would we get our engineers, physicians, geneticists… ? Science-related jobs are often among the best one.

#2. Politically, it would certainly help if most people had a good general knowledge of science. Science is a powerful force, and as we live in a democracy the ignorance of the public opens the door to populism and confusion (it's the case with global warming "scepticism", stem cell research, evolution, homosexuality, et cetera...).

#3. Intellectual development. Science is hard; it requires the child to build a strong intuition on complex, and sometime counterintuitive, notions. I think science is not taught very well, however, I must admit that I hated science until I started reading about it on my own.

Why is "Evolution, Morphology and Exobiology" a subsection ?

I dislike experiments and I lack the patience (accuracy) to do them correctly.

No, not at all. You can be a great scientist and a christian at the same time.

yep, and you can believe in astrology and be a great scientist.

There's still, IMO, a contradiction. Science is all about not having faith. Religions require that someone believe in something with no evidences, most of the time simply because that person was born in this religion.