Evolving the Musculoskeletal System

In which adult skeletal system? In basal chordates (e.g. lancelet) there are muscles without any bones. Why are my legs just the right length to reach the floor?Why is the shape of the muddy lake bottom just the right shape to fit shape of the water in the lake?Why is the riverbed of the Mississippi just the right shape to fit the river?

Example of mutation giving rise to detectable musculoskeletal change in hominid evolution:

quote:

---

Nature. 2004 Mar 25;428(6981):415-8.

​

Myosin gene mutation correlates with anatomical changes in the human lineage.

​

Stedman HH, Kozyak BW, Nelson A, Thesier DM, Su LT, Low DW, Bridges CR, Shrager JB, Minugh-Purvis N, Mitchell MA.

​

Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

​

Comment in:

​

Nature. 2004 Mar 25;428(6981):373-4.

​

Abstract
Powerful masticatory muscles are found in most primates, including chimpanzees and gorillas, and were part of a prominent adaptation of Australopithecus and Paranthropus, extinct genera of the family Hominidae. In contrast, masticatory muscles are considerably smaller in both modern and fossil members of Homo. The evolving hominid masticatory apparatus--traceable to a Late Miocene, chimpanzee-like morphology--shifted towards a pattern of gracilization nearly simultaneously with accelerated encephalization in early Homo. Here, we show that the gene encoding the predominant myosin heavy chain (MYH) expressed in these muscles was inactivated by a frameshifting mutation after the lineages leading to humans and chimpanzees diverged. Loss of this protein isoform is associated with marked size reductions in individual muscle fibres and entire masticatory muscles. Using the coding sequence for the myosin rod domains as a molecular clock, we estimate that this mutation appeared approximately 2.4 million years ago, predating the appearance of modern human body size and emigration of Homo from Africa. This represents the first proteomic distinction between humans and chimpanzees that can be correlated with a traceable anatomic imprint in the fossil record.

---

In summary:A mutation in a gene responsible for strong jaw muscles in the hominid lineage resulted in a weaker jaw muscle. This allows for both a weaker jaw bone and weaker bone in the cranium as anchors for this muscle. Without the need for a strong, bony anchor in the cranium the cranium was allowed to grow larger without being comprimised by chewing. This is also seen in the shrinking of the lower jaw in hominids leading to modern humans.

We do see that the differences between species is due to a difference in DNA. We also observe that mutations change DNA, causing it to be different both from the previous generatoin and different from other species. We also observe that advantageous differences are usually kept and amplified in a population. On top of all of that, we observe that this process results in a nested hierarchy.So what do we see in the comparison of genomes, the comparison of morphology of livings species, and the fossil record? The exact pattern we would expect to see if this process were active in the past. We see simpler organisms earlier in history, modifications of those simpler organisms over time, and then the final modifications in modern organisms. All of these modifications fall into a nested hierarchy, both in the present and in the fossil record. We see the modifications of the lobe finned fish morphology into a basal tetrapod. We see the modifications of this basal tetrapod into a reptile. We see the modification of this reptile morphology into a mammalian morphology. We see the modification of this basal mammal into a primate, an ape, and into us. At the same time numerous other lineages are branching out and doing the same thing. Are you to say that we are just dreaming up all of this, that we have absolutely no reason to state that morphology is changed in a step by step process resulting in a branching tree? Are you sure of this? Although I don't know of any examples off hand, I am quite confident that such individuals do exist at least for the ligaments and cartilage. That is something I have wanted to ask the ID crowd for quite some time now.

Compare the human and chimp genomes. Amongst those differences are the beneficial mutations for chimps in their environment and the beneficial mutations in our environment. Those differences are responsible for the morphological and physiological differences between chimps and humans. It is a rather simple concept.

Then there are the Vadoma tribe where a dominant mutation in chromosome 7 is quite common. It results in a completely different foot morphology. The Vadoma people claim that it doesn't impede running at all.

Until you demonstrate that it is perfect then there is nothing to explain. You might as well be asking us for an explanation for flying reindeer. First thing we do is throw out the coccyx. That would really improve the design right there. So I have just fulfilled your requirements. I guess it isn't designed afterall. Get thee to a comparative vertebrate anatomy class at your local university. It will do you a lot of good. What you will find is that banded muscles are derived from unbanded muscles in more primitive vertebrates such as fish. You might as well ask that a new continent jump out of the ocean and develop a river that exactly matches the route of the Mississippi in order to accept the idea that the channel of the Mississippi was carved by erosion.

In which post did one of "us" describe it as a "miraculous designing feat"? You seem to be putting your own conclusions into our mouths. It is up to you to show that it is impossible. You have been parading your beliefs around as facts, such as evolution being impossible and miraculous. While this may stimulate you in some way, the rest of us are less than impressed.Edited by Taq, : No reason given.

Call it whatever you want, but the point is that you only needed the appearance of a single fully formed organism. All of the descendents of that first fully formed organism will likewise be fully formed. In the line of inheritance from that last universal common ancestor to all living species there was an unbroken chain of fully formed species.

You have been taught about the the birds and the bees, have you not?Edited by Taq, : No reason given.

Wrong question. Are they new body parts or modifications of body parts from previous generations?

The enzymes that copy DNA do not perfectly duplicate the DNA sequence from one strand to the other. In the molecular biology trade we call this infidelity. You can actually purchase different polymerases that have lower or higher fidelity which relates to the rate at which they produce mutations.I guess you can call it an "accident" if you want, but it just so happens that this is just the way things are. There is no "eye" gene. Rather, it is a sequence of different genes being turned off and on in a certain order that results in an eye. There are master genes, or master switches if you will, that get the ball rolling. They are called hox genes. What they did in that experiment was mess around with the hox genes. Why doesn't it verify it? We see the exact transitionals we should see if evolution is true. We see the primitive conditions in living organisms, for Pete's sake. There are over 100 hundred known coelacanth species, to start off with. The living species of coelacanth is different than any known fossil species. So first off, it has changed. Seconly, no one claims that it was the coelacanth that walked up onto land and became the common ancestor of all tetrapods. And as to the mutations? They are in the genome of the coelacanth. Where else did you expect to find them? In a cloud? I fail to see how conservation of morphology is evidence against natural selection. Care to explain?Also, are you saying that we should NOT see fossils with a mixture of modern human and basal ape features if evolution is true? Can you please explain this?

As does the theory of evolution. We are apes, as was our common ancestor with other apes. Apes giving birth to apes. So I would hazard a guess that you don't have a problem with that?Also, fish are vertebrates and we are vertebrates, as was our common ancestor. Vertebrates giving birth to vertebrates. So I would assume you have no problem with this either?

That is only a single candidate. You need to show the probability of every candidate occuring, even those that have not been proposed yet. What you need to find is the simplest candidate possible that does evolve and then calculate the probability of that candidate coming about through inorganic chemistry.

That is for just a single candidate, as stated in the quote. If life arose through a much simpler replicator then your probabilities are meaningless. What you need to show is that this is the simplest candidate possible.

Then let's see those numbers and the formulas that you used to calculate those numbers with respect to the evolution of the musculoskeletal system. What are you basing this opinion on? Then surely you can present this evidence for the creation of the musculoskeletal system by this maker. If you can not present this evidence then perhaps it is you that is ignorant.