Examples of Speciation

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Posted by J.H. [JH] on November 28, 1999 at 09:34:45 {hcnmikA.FkwxcT1WLj/AHR5JhS9/hc}:

I found an old message I posted to H2O some time ago, in reply to the infamous false prophet YouKnow, dealing with evolution and speciation. It contains some references and concrete examples of speciation.


YK,

: It is the basic assumption that one kind of creature mysteriously transmutes into another kind.

Not mysteriously at all. Your ignorance does not make a "mystery."


Once upon a time, horses and donkeys were the same species. I doubt any creationist will deny this self-evident fact. Today, these two different species are half crossfertile; their offspring is sterile. Naturally, if we go back some generations, we would find (pre)horses and (pre)donkeys that were perfectly interfertile and produced a form of mules that were themselves fertile. If we add some generations into our future, there is no doubt they will be unable to produce any offspring, as the genetic gap widens. Lions and Tigers can produce offspring, cats and dogs can not. If we follow cats and dogs back to their ancestors, we will find two species that were theoretically interfertile, and later almost fertile (offspring was sterile), and eventually the situation we have today. If we go further back, we find a common ancestor for cats and dogs.

An example of species that are not crossfertile and yet obviously (even creationists admit this) come from the same ancestor is the Finches that Darwin observed on Galapagos. The punchline? They don't crossbreed. (see Laurie R. Godfrey, Scientists Confront Creationism, New York: W. W. Norton & Company, 1983. pp. 167-169)

Your assertion we have not observed speciation is false. I have appended some paragraphs from my Creation book debunking that deals with this argument. See below.

: The law of Jehovah states in Genesis the first chapter: 'according to their kinds.' This law has never been violated.

Only because "kinds" is scientifically undefined, and creationists desperately want to avoid defining the term, because that would leave their claims open to actual counter-examples. You will define "a kind" as whatever has not been directly observed to evolve. That is circular argumentation.

Logic dictates certain conclusions that follow from the observed facts. Nobody can prove by observation that if you add 2 billion oranges with 2 billion oranges you get 4 billion oranges. It is simply a logistically infeasible task. But logic dictates that if you managed to get enough oranges, the this would happen. Only in biology do creationists refuse to follow the arguments that follows from universal rules of logic and the actual observations we have.

One example: You can claim that continental drift is not really observed, in the sense that nobody has seen the Atlantic Ocean be created by landmasses slowly drifting apart over millions of years. Yet, by accurate measurement, we can prove that today the continents drift a certain number of millimeters apart every year. Add up with the known age of such continents, and we have continental drift. Only a complete fool will deny that if continents drift 1 cm every year, they can drift 100 cm in a century or 10,000 kilometers in a billion years. In the same way, if species can vary so much in the time we have observed it directly, it is a totally logical conclusion that they can vary thousands of times as much as they now do, given a thousand times more time. This is pure logic. Creationists claim that there exists some genetic law against such natural variation, and that's pure nonsense. It's a fairy-tale unconfirmed by facts; an unobserved (and disproved) "law" that creationists have made up just to protect their beliefs. Direct evidence from the DNA, from fossil records and from a large number of other evidence shows conclusively that this is exactly what happens. And unless youcan demonstrate that an extrapolation of the observed phenomena over time does not add to speciation to a degree that even you will have to admit that a different "kind" is produced, your argument from refusal to think is just that.



Speciation observed
"Three species of wildflowers called goatsbeards were introduced to the United States from Europe shortly after the turn of the century. Within a few decades their populaltions expanded and began to encounter one another in the American West. Whenever mixed populations occurred, the specied interbred (hybridizing) producing sterile hybrid offspring. Suddenly, in the late Fourties two new species of goatsbeard appeared near Pullman, Washington. Although the new species were similliar in appearance to the hybrids, they produced fertile offspring. The evolutionary proces had created a separate species that could reproduce but not mate with the goatsbeard plants from which it had evolved."

The article is on page 22 of the February, 1989 issue of Scientific American. It's called "A Breed Apart." It also tells about studies conducted on a fruit fly, Rhagoletis pomonella, that is a parasite of the hawthorn tree and its fruit, which is commonly called the thorn apple. About 150 years ago, some of these flies began infesting apple trees, as well. The flies feed an breed on either apples or thorn apples, but not both. There's enough evidence to convince the scientific investigators that they're witnessing speciation in action. Note that some of the investigators set out to prove that speciation was not happening; the evidence convinced them otherwise. In 1916, a single pair of wallabies escaped from a zoo in Oahu. They survived and bred in the wild, and now there is a whole population. They are smaller and more lightly colored than the Aussie wallabies. They eat Hawaiian plants that are poisonous to the Aussie wallabies, because they evolved a new liver enzyme to detoxify them. They can no longer breed with the Australian wallabies, so they qualify as a new species.

Sources: "Instant Evolution", Science Digest, July 1982 Saladin / Gish debate at Auburn University at Montgomery, 24 March 1984



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