From “Searching for the Origin of Muscles” (ScienceDaily, June 28, 2012), we learn:
Phylogenetic comparisons showed that one of the crucial structural proteins of striated muscles of vertebrates, a “myosin” motor protein, originated by gene duplication. “As this specific myosin has so far only been found in muscle cells, we expected that its origin coincided with the evolution of muscle cells. We were very surprised to see that the ‘muscle myosin’ evolved probably in unicellular organisms, long before the first animals lived,” explains Ulrich Technau who led the study.
In sponges, the “muscle myosin” plays a role in regulating water flow.
Jellyfish are over 600 million years old, and
… possess striated muscles. Due to the striking similarities between striated muscles of vertebrates and jellyfish, it was so far assumed both striated muscle types share a common origin. In fact, jellyfish striated muscles also express the ancient “muscle myosin,” but they lack several essential components that are characteristic for the structure and function of striated muscles of “higher animals.”
This indicates that despite their striking similarities, striated muscles of jellyfish and “higher animals” have evolved independently.
The significance of convergent evolution for Darwinism is this: Life forms usually do not randomly evolve a complex trait and pass it on (natural selection acting on random mutation, as Darwin taught). They do not create a great, tidy, and non-goal directed “tree of life”.
They are goal directed in seeking solutions to mutual problems, and creatures only distantly related often converge on the same solution – a possible solution in a wilderness of non-solutions. The materials used were there long before the need arose in many cases; they were not “evolved” for the purpose.
Showing how Darwinism could have explained how it could have happened is a waste of time if it didn’t happen that way.
Some form of intelligence, perhaps internal, seems to be at work, but we have only begun to grasp the significance of the pattern, hindered by a century of Darwin’s dead idea.
See also: Convergent evolution: Separate development of the genetic patterns of intelligence?
Convergent evolution: 359 million year old eel fossil had spine like land-dwellers
Nature (journal): “Tearing apart” the traditional animal family tree