h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I wondered how long it would take you to find this thread Adib

A nematode is an animal, as are we. A banana is not and we share 50% of our genes with it. 75% is therefore a comparatively large amount. There are fundamental metabolic processes to all life (such as respiration, cell cycle control), that are all controlled from a fundamental set of genes whose roles are so important to the functioning of a life-form that they have been preserved throughout evolutions history.

Also, phylogenetics is a little bit more complex that just comparing how much of the genome is the same. Genomes operate on many levels and it is too simplistic to say that we are 95% related if we share 95% of DNA with species x. But still, Chimps and humans share a common ancestor that is not all that distant in the past.

Also, the current estimate for the number of human genes is from 30,000 to 40,000.



Ste

Actually I was invited to this site from Gilford he said there are no creationist on the sight so here I am.
I read some where that apes have one less cromosone than us but potatos have the same number as us. Don't know if its true?

Adib

"...According to the family tree made by evolutionists, the Chordata phylum, which man is included in, and Nematoda phylum were unrelated to each other even 530 million years ago. This makes the %70 similarity - a very high figure for humans and nematode worms, completely different and dissimilar life forms - does not imply any evolutionary relationship."

I'm afraid that isn't really supportable. I assume that when you say 'unrelated to each other', you really meant 'didn't have a living common ancestor at the time', but stating that evolutionary biologists believe there was no relation is wrong (it'd be like someone saying offspring of mine many generations hence would be unrelated simply because I'll be dead by then).

Percentage figures can be misleading, since once evoloution has hit on a useful or vital chemical (or set of chemicals) there is a large chance the genes for producing those chemicals will be conserved in future generations - and so we share many genes with primitive organisms, since at the biochemical level, much of what we do (metabolising food, degrading or recycling waste products, contracting muscles etc.) isn't very different from what they do.

What makes you think that 70% is a very high figure?

What really matters are the *relative* figures - if we turned out to be *more* related to nematodes than chimps, that would be hard to explain, but as long as our genetic relationship tallies with our expected relationship from non-genetic angles, there really isn't a problem.


"...For that reason, there is no scientific basis for claiming that all the genes of man and ape are 98 % similar only because of the similarity in 40 out of 100,000 proteins. Scientists have not worked out the entire chimp DNA code and so they can't see how much it actually is close to humans."

I'm confused - given that statement, do you agree or disagree with the article stating it was roughly 95%? If you don't believe any realistic measurements are possible, why bother commenting beyond just stating that?

Anyway, I'm not sure people were claiming that "all the genes were 98% similar" - they could have been claiming that 98% of the genes were pretty/broadly/highly similar, or something else.

I'm sure a biologist can give more information on the basis of the 98.5% figure - since it dates from well before mass DNA sequencing, I assume some rather coarser method was used to get an estimate?

Regarding chromosome numbers.

Imagine there are many people in a town who each have a very small book collection. If I have 26 books, and someone else has 25, but 24 of theirs are the same as mine, and the remaining one is the same as my remaining 2 stuck together, you'd say we had a much more similar collection than if you compared me with someone else with 26 books, only half of which were the same as any in my collection.

That's roughly the picture with numans, chimps and potatoes.

Or anotehr wat of saying it the number of chromosomes doesn't really matter, but what they contain. Chromosomes are just a method of packaging the DNA so that it fits into the nucleus.

I shall now go dack and read the rest of the b-log to find out what you is talking about now..

Ok. Look I have never seen a fossil I could see as being a link between one animal and another in a chain of fossils that does not have multipule physical and biological changes in it. Can you tell me any?

This is my part of I don't want to piss any one of so ask rather than state things theroy.

Adib

The questions are - What is going to count as a "transitional" fossil?
and How complete is the Fossil Record?

As an example - Fossil evidence of the evolution of land based mammals into the whales and dolphins was for a long time challenged by creationists on the basis that there were no transitional fossils.
A handful of intermediate fossils have now been found, but they are still significantly different to both the land based mammals and the whales. According to the creationists this means that we are now missing TWO sets of transitional fossils. Between A and B and between B and C, rather than just one, between A and C.

In any case, every fossil that comes from a species that was not the end of its evolutionary lineage is a transitional fossil. It comes between what went before, and what came after.

For a genuine test one needs some criteria that falls between discounting any fossil as transitional (by definition) and one that includes every fossil as transitional (by definition).

So what are the criteria?

Noggin

What about land animals. Why would a aquatic animal produce sweet glands, limbs for movement on land, Kidney or is live system, a new skeleton able to support its on wieght and lungs when it lives in water? Or are you going to say that by chance mutation a animal did produce all these things and then ended up on a beach plus its eyes would have to change as they are not designed for looking above water.
As for the fossil thing. My idea of a linking fossil would have all the traces of the animal it was supposed to be from and have a new feature not of the originle animal and not fully in working order. For instance a dino is not going to go from having fore arms to wings in one step is it. There is mager genetic reconstructing and that would take time.

Adib

I recently saw some transitional fossils between dinosaurs and birds in the Natural History museum - from the Lionyang [i think] region of China.

The big problem for evolutionary theory here is that wings, just like land skeletons etc that you mentioned, are not useful for flight until they are fully formed. Which can't just happen in one mutation as you rightly say.

So small adaptations must have occurred which later - by chance - were co-opted for flight. For example, a dinosaur similar to all others but with a fluffy coat - originally for insulation, dispay etc. Then one with longer and longer forearms providing advantages in grabbing prey - later found useful in a rudimentary wing.

Evolution is all chance and long, long periods of time. Of course, for every adaptation that later proved useful for something else, there must be millions that were absolutely useless. We, however, only see the successful ones whose adaptations are passed on, giving the illusion of design.

Actually, land skeletons can be quite useful even in a primitive form. At a point in time when there were few (or no) competitors or predators, even a bungled attempt at walking (or water-adapted eyes) could be quite useful.

Given the amount of food present in the tidal zone, allied to the risk of being stranded in drying-up pools at the tide recedes, a simple method of locomotion to enable getting back to deeper water could have had a significant selective pressure in its favour.

As far as wings are concerned, given the mammals, amphibians and snakes which are currently adapted for gliding, it depends what you mean by 'useful for flight' and 'fully formed wings'. Free flight is only one end of a spectrum.

Well what about flys. Most insects have wings how do you explain that they have wings. An they can beat there wings some thing like a hundred a sec and if one wing went out of coordination with the other it would crash.
Plus Feathers even on birds like arcyheoptrix (Sorry about the spelling) were designed for fligh plus gliding is harder than normal flight. have you tried holding your arms out for hours on end its hard to do. The albotros comes over this with a unique muscle system where when its wrings are spread its muscles are fairly relaxed.

Adib

Ah that's true. However flight feathers are complex structures, it would be unlikely that their first precursors conferred much or any advantage in either gliding (the top-down theory) or running leaps (bottom-up). These first 'transitionals' had literally fluff without the structure of modern feathers. Which still leaves the problem of what selective advantage they originally gave.

Similarly, the swivel wrist joint that modern birds use for their flying action is found in ground-dwelling dinosaurs before the appearance of flight feathers or even 'fluff'. So how do that arise in the first place? Possibly for catching prey. I don't think this is a big problem - it just implies that evolution is based more on luck and subsequent opportunism, than gradual ongoing design towards a predestined goal.

I read some where that a scientist had compared the wrist of early dinosaurs live velociraptor and others likely to have been the ones to evolve in to birds and compared it to the early birds including above mentioned bird I can not spell and found there to be no resembalance. I will try to find out who and stuff.

Adib

Heh i missed your post Muzaak - i was replying to the one above...

I totally agree in that its just preposterous to suggest these specialised systems could arise just like 'that'. Evolution must occur in tiny steps. On top of that each tiny step has no foresight of the structures that may eventually be based on it.

But i don't think this sinks evolutionary theory, just requires a different approach - above. Just bear in mind the mind-boggling lengths of time, and numbers of unsuccessful variants. The ones we see in the fossil record and today are just the 'selected' tip of the iceberg, so to speak.

Hmmm flies.

There's a line of thought that reckons that insect wings started as a body temperature control mechanism; but in an an organism as small as a fly even a small wing area would give considerable bouyancy for gliding. Cordination of gait in land animals, and probably of wings in flying animals, is achieved by groups of neurons that function as oscillators. You'll have to ask the experts how that works exactly, but if an insect has the neural machinery for controlling its legs, the same machinery can be coopted to controlling wings.

As a thought on how genes build bodies that work, consider the case of a human child born with an extra finger on each hand (it's rare, but it happens). These children have normal use and feeling of the extra digit. The argument against evolution based on the need for a whole series of genetic changes (governing brain, blood vessel, and muscular changes etc) to be exactly coordinated has in these cases either happened against all the odds, OR phylogeny doesn't work the way creationists think it does.

Noggin

Yes but its not mind bogling amounts of time. After the earth was fromed and cooled down enother then life could begi. So essentially evolution has got a limit of time on a earth perspective.

Adib

Limited yes, but still very long from a human perspective. Around half a billion years from the time land animals first appeared. Long enough to throw up a *lot* of mutations. It would be interesting though, to look up some estimates of the avergae mutation rate and whether that varies through time.

Well some one did work them out but I will that at the end of this.

When looking at fossil I can't help to notice that they have supposedly evolved anti predotury devices before they were needed.
For instance one of the creatures which suddenly emerged in the Cambrian Age was Hallucigenia, seen at top. And as with many other Cambrian fossils, it had spines or a hard shell to protect it from attack by enemies. The question that evolutionists cannot answer (I have found so far) is how could they have come by such an effective defense system at a time when there were no predators around? The lack of predators at the time makes it impossible to explain the matter in terms of natural selection.

Another thing is that the Burgess Shale fossil bed is accepted as one of the most important paleontological discoveries of our time. The fossils of many different species uncovered in the Burgess Shale appeared on earth all of a sudden, without having been developed from any pre-existing species found in preceding layers. Because of the findings there is a serious debate amongst evolutionists about well evolution and how it started.

It seems odd to me that fossils from one small locality, no matter how exciting, should lie at the center of a fierce debate about such broad issues in evolutionary biology. The reason that it does is that animals burst into the fossil record in astonishing profusion during the Cambrian period, seemingly from nowhere. Increasingly precise radiometric dating and new fossil discoveries have only sharpened the suddenness and scope of this biological revolution. The magnitude of this change in Earth's biota demands an explanation. Although many hypotheses have been proposed, the general consensus is that none is wholly convincing.

Plus recent findings show that almost all phyla (the most basic animal divisions) emerged abruptly in the Cambrian period. An article published in the journal Science in 2001 says:

"The beginning of the Cambrian period, some 545 million years ago, saw the sudden appearance in the fossil record of almost all the main types of animals (phyla) that still dominate the biota today."

The same article notes that for such complex and distinct living groups to be explained according to the theory of evolution, very rich fossil beds showing a gradual developmental process should have been found. So far none has been found.



an average molecule comprising of 500 amino acids:

1. The probability of the amino acids being in the right sequence:

There are 20 types of amino acids used in the composition of proteins. According to this:
-The probability of each amino acid being chosen correctly among these 20 types = 1/20
-The probability of all of those 500 amino acids being chosen correctly = 1/20500= 1/10650
= 1 chance in 10650


2. The probability of the amino acids being left-handed:


-The probability of only one amino acid being left-handed = 1/2
-The probability of all of those 500 amino acids being left-handed at the same time = 1/2500 = 1/10^150
= 1 chance in 10^150


3. The probability of the amino acids being combined with a "peptide bond":
Amino acids can combine with each other with different kinds of chemical bonds. In order for a useful protein to be formed, all the amino acids in the chain must have been combined with a special chemical bond called a "peptide bond". It is calculated that the probability of the amino acids being combined not with another chemical bond but by a peptide bond is 50%. In relation to this:


-The probability of two amino acids being combined with a "peptide bond" = 1/2
-The probability of 500 amino acids all combining with peptide bonds = 1/2499 = 1/10^150
= 1 chance in 10^150


TOTAL PROBABILITY IS: 1/10^650 X 1/10^150 X 1/10^150 = 10^950
1 chance in 10^950

http://www.hyahya.org/miracles_of_the_quran_01.php

Yeah you can go there and read up on it but I don't like the fact that he says this proves creation all the time. If you have two theroys and one 'is' proven wrong does not mean that the other is right. It just means there is more weight supporting the other theroy. I personally think Creation is right but I can't say creation is proven as the evolution article is wrong.
Any way my last message is not finished I accidently put it on so I will put the proper one on after this one. The trouble with having multiple windows open.

Adib