Refuting 25 creationist claims - Claim 16 through 20
Agreed that the change in asexual reproduction to sexual in some organisms is not easy to explain. There is no consensus as to the actual origin of sexual reproduction, though there are several proposed methods. However, lack of an adequate scientific explanation doesn't implicitly require that their answer is the correct one.
17. Human speech and languages did not evolve - in fact the best evidence is that languages "devolve". Speech is uniquely human. Furthermore, studies of 36 documented cases of children raised without human contact show that speech appears to be learned only from other humans. Apparently, humans do not automatically speak. If so, the first humans must have been endowed with a speaking ability (intelligent input). There is no evidence that speech has evolved.
The author of the list must not read up on the latest discoveries. Here is an article from Science (from 2004) that discusses this very topic.
18. Codes and programs (DNA and the genetic code) are produced only by intelligence. No natural process has ever been observed to produce a program.
Well, this is interesting. The author once again is trying to make evolution responsible for explaining the origin of life. Since there is a viable explanation for how natural processes can be responsible for changing the "program", it really isn't a great leap to think that a natural process might be responsible for the program to begin with.
19. The existence of similarities between different forms of life implies a common designer, not a common ancestor. One would not, for example, assume that a submarine evolved into an "amphibious" seaplane, which in turn evolved into a passenger airliner. All might have common features such as propellers, internal combustion engines, and metal frameworks - but this is simply an indication of a common intelligent designer (man), not a common ancestor (the submarine).
What, exactly, invalidates the concept of common descent when you see similar features in ancestor species? Wishful thinking?
20. Many single-celled forms of life exist, but there are no known forms of animal life with 2, 3, 4 or 5 cells, and the forms of life with 6 to 20 cells are parasites. If evolution occurred, one should find many forms of life with 2 to 20 cells as transitional forms between one-celled and many-celled organisms.
Another claim of what they think we should expect, without an explanation of why we should. I see no reason to think that 2 celled organisms are necessary for evolution to be true, or that evolution even predicts that any would exist.