Thanks Dinosaur and John Connellan for responding to my post. Hopefully Dinosaur I will have an opportunity to look in more detail at your post on the weekend. My response to John Connellan is as follows. Robert wrote: The question we need to ask is how was the genetic code for the long neck (or the eye) originally found. For if the design was not there then it could not be selected by “natural selection”. In other words there would be no complex design from which natural selection could choose and hence no complex creatures You accept that the body plan can be changed by mutation. But in the first post to this thread I suggested that the arms and legs of our own species might have been exchanged for flippers (hence the early intercontinental migration) and for this I was heaped with scorn. I am of course not arguing with the fact that new genes are found by mutation. As I understand it a mutation is merely a change to the existing DNA. If species are to change (and they always do change) then there must be mutation. It appears your argument goes like this: Look there is a mutation, those kids are born with one eye, this proves that mutations happen, so this is the way we all evolved. But can this sort of mutation, which is really an accidental stitching up of our DNA at birth, create new and complex designs? Designs so complex that the best minds of the 21st century can not match their sophistication. The chance of this happening by "spontaneous mutation" (or by what others call random mutation) is ZERO.
We know DNA is a substance for hedidity & sugar deoxyribose, phosphate are part of it. What is the role of sugar deoxyribose, phosphate in heredity or mutations as mutations are just defined in terms of changes in bases adenine, thymine, guanine, and cytosine not in sugar deoxyribose, phosphate. Are these can be somewhat changed on any mutation/damage?
Yes! The 21st century is only 100 years long. Life evolved over approx. 3500000000 years. Its actually very high. If mutation can produce an organism with one eye in just one generation, imagine what it could do in the time specified above!
I am sure they can be damaged but they are not coding molecules so they will not be passed on. If damage happens to the backbone of the DNA, apoptosis will remove the affected cell and nucleus.
But can't these do some defects in chain of DNA? Is there any study on defects in these sugar deoxyribose & phosphate esp.phosphate? Can't there be any defect/problem in joints? Please Register or Log in to view the hidden image!
hopefully, this hasn't already been mentioned, I have limited time to respond: Spurious: there a a couple studies of mitocondrial DNA which give very, very, strong evidence that sometime in the past 70,000 years, the human population was significantly reduced worldwide. It appears that humans were nearly wiped out, but universally, throughout the world. There's your bottleneck. edit: source: http://news.bbc.co.uk/1/hi/sci/tech/166869.stm
Can't there be short or long chains(weak links may not possible) of nucleotides in DNA which can pass into new generation?
U see, the genetic software of our bodies is highly resilient to such damage. the reason is of course, natural Selection. It operates very actively on DNA. Anybody who passed a broken fragment of DNA into a new generation would find that the offspring have lost a number of genes. This would generally make the offspring unviable either in that it would die very quickly or that it wouldn't reproduce. Hence the phosphate bonds are quite strong and our DNA repair mechanisms are amazing today.
Means: in every case DNA in all gemetes will be the same in structure except the differance in coding of four bases?
What about chromosomes, can there be defects in their protien structure which may lead to genetic or hereditary defects? ( genetic & hereditary seems to have became two differant aspects here now)
If there is a major problem with the structure of the DNA or chromosome, replication might not occur at all and the mitotic cycle may be interrupted!
John, thanks for clarifying it. It shows that nothing defective in structure of chromosomes except bases codings can be possible to be passed onto new generation by chromosomes. Now what about the possibility of structural defects in human egg/ovum & sperms( I mean other than chromosomes in gemetes) which can effect the embryo or fetus, structurally?
Strucutural diseases of the egg will almost certainly lead to large debilitating physical disability in life (or death/miscarriage depending on severity).
John Collellan Expansion of the Universe – Precise to 10(-18) From Paul Davies, Superforce – page 184 Careful measurement puts the rate of expansion very close to a critical value at which the universe will just escape its own gravity and expand forever. A little slower, and the cosmos would collapse, a little faster and the cosmic material would have long ago completely dispersed. It is interesting to ask precisely how delicately the rate of expansion has been 'fine-tuned' to fall on this narrow dividing line between two catastrophes. If at time one second (by which time the pattern of expansion was already firmly established) the expansion rate had differed from its actual value by more than 10(-18), it would have been sufficient to throw the delicate balance out. It is difficult to have a mental picture of a number as large as 10(18). Perhaps a better idea would be to count out some grains of rice so we can think in terms of volume. 1,000 grains of rice will fill a tablespoon and weigh 20 grammes. 50 full tablespoons is then 1 kg and 50,000 grains of rice. A ton of rice will be some 50 million grains. For readers who cannot envisage a ton of rice, consider that the average courier truck or pick-up is a ‘1 tonner’. The larger tip-trucks we see carrying earth on roadworks are mostly licensed to carry 5 tonnes. This then, would hold some 250 million grains of rice. One hundred 5 tonne tip-trucks will hold 25,000 million grains. This means that 10 million, million, million grains of rice on 100, 5 tonne trucks would need 400 million trips. If each truck made one trip every hour (24 trips a day 365 days a year) it would take 45,600 years to carry all the rice away. There are 100,000,000,000 stars in 100,000,000,000 galaxies. This is 10(21) or three more zeros than the above. So if all the stars were grains of rice this would mean that 10,000 million, million, million grains on 1,000, 50 tonne trucks would need 4,000 million trips. If each truck made one trip every hour (24 trips a day 365 days a year) it would take 456,000 years to carry all the rice away. “Compass – Testing God”. http://www.abc.net.au/compass This program was aired on ABC TV on 7th March 2004 and gave the “universal constant” as 10(-120). This figure reflects the fact that, not only did the expansion of the universe have to match the gravitational force holding it together, but so many other factors had to be so finely balanced or our universe as we know it would not exist. The probability of any universe that could support life is one chance in 10(-120). 10(120) is ten followed by 120 zeros.
Who cares if the universe is so delicately balanced. Life would still evolve had the cosmos been expanding slower and also if it was expanding quicker! My last post was not even about this. I was explaining to u why life can be so complex and sophisticated.
