If you find a robber fly in Tenerife, you will be face to face with an insect that is found nowhere else – and whose evolution may be a direct consequence of the great wealth of species on the Canary Islands, according to new research.
Posted on 04/20/2005 5:17:33 PM PDT by PatrickHenry
A unique fly from the Canary Islands has helped shed light on one driving force behind the birth of new species, Nature magazine reports this week.
The robber fly is found nowhere else, and scientists speculate that the rich biodiversity on the islands may actually have led to its emergence.
The researchers think sharing an island with a myriad of other lifeforms may push one species to evolve into another.
This new theory adds fresh insight into how biodiversity arises.
"Why some areas contain greater species diversity than others has been a fundamental question in evolutionary ecology and conservation biology," said co-author Brent Emerson, of the University of East Anglia, UK.
Genetic drift
It is thought "speciation" -- the evolution of a new species -- can occur when two populations of the same species become isolated, allowing them to "grow apart" genetically over the course of many generations.
Eventually, the two populations become so different that if they were to meet again they would no longer be able to breed, meaning they had become separate species.
One species can also evolve into another if strong selective forces are placed upon it (where certain genes or genetic traits are favoured by natural selection), or if its population is small enough to allow for "genetic drift", which happens when certain traits are lost -- or become proportionately more common -- simply because the gene pool has shrunk.
But exactly what drives speciation is still not fully understood by scientists, and it is an area of intense research.
By carefully studying animals and plants in the Canary and Hawaiian Islands, Dr Emerson and his colleague Niclas Kolm were able to show an apparent link between biodiversity and the evolution of new species.
If you find a robber fly in Tenerife, you will be face to face with an insect that is found nowhere else – and whose evolution may be a direct consequence of the great wealth of species on the Canary Islands, according to new research.
They found that endemic species, such as the predatory robber fly (Promachus vexator), are more common in places that are bustling with many different species. Therefore, they speculate, new species are more likely to evolve if they are surrounded by an already rich biodiversity.
Species competition
"Imagine you have an island colonised 100 species and a similar island colonised by 10 species," explained Dr Emerson. "If you leave that for a period of evolutionary time, the percentage of entirely new forms will be higher on the island with 100 species on it."
The researchers can think of three reasons why this might be the case. First, species that are forced to share a space with a lot of other species usually have smaller population sizes. That means they are more susceptible to genetic drift, which can speed up speciation.
Secondly, islands with a rich biodiversity have more habitat complexity. In other words, instead of just one habitat -- say, grass -- there is, for example, grass, shrubs and trees. That means species are more likely to evolve new adaptations and, eventually, become different species.
Thirdly and, the researchers believe, most importantly, competition between species can encourage speciation.
"We think the islands with more species have an increased interaction effect - and that is the most significant thing," said Dr Emerson. "So the more species you have, the more, as an individual species, competitors and predators you are facing.
"And that puts pressure on you that can lead to your extinction or you can adapt to that pressure and survive and that would result in a new species forming."
Tropical diversity
This new research could help explain why islands in warm areas (which tend to start off with a richer biodiversity than colder areas), like Hawaii and the Canary Islands, tend to have a high proportion of totally unique species.
Professor Axel Meyer, of Konstanz University in Germany, who is eminent in the field of speciation, says the research is very interesting -- if it stands further scrutiny.
"It is very thought provoking," he told the BBC News website. "I'm sure it will have people rushing to their computers to see whether this pattern holds up and it will be interesting to see if it does hold up in other systems."
He also stressed that a rich biodiversity could not entirely explain a rich biodiversity because, of course, you had to start somewhere.
"They are saying that if you have biodiversity it will create more biodiversity - I can buy that. But it still doesn't explain the initial step: how do you get more biodiversity in the first place?"
FR's geologists do a far better job explaining the difference between the layers at Mt. St. Helens and the layers in the Grand Canyon. However, just for starters, how do you account for the fossilized rain drop patterns found halfway through the columns? Or the fossilized animal burrows, or fossilized animal footprints, etc.? You cannot, but it won't matter because you'll come back with the same benighted crap on the next thread completely oblivious to all that has gone on before.
Oh well, I hold out greater hope for the intelligence of the lurkers.
I've given up on factual explanations to the worst of this bunch. Satire is about the only proper tool to use on them.
Gravity is an observable phenomenon. Evolution isn't.
See the difference?
Not when they're talking about research. Buy a clue.
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Testy testy.
Be more specific next time.
By the way, don't research scientists use laws and constants anymore? (Ohms Law, Planks Constant, Laws of Thermodynamics)
You scared me for a minute there, fella. I'd thought I'd wandered into an alternate universe (I've been known to do that from time to time).
There are many possibilities. I understand that are more marine animals that burrow than land animals. So burrowings themselves don't establish anything, but rather the kind of animal that created the burrowing.
There may be layers that predate the flood and layers that occurred afterwards. In addition the flood was a year long event. There may be periods during which land was exposed prior to being reflooded by the release of waters trapped at higher elevations.
However if it was laid down over eons, as evolutionists claim, the burrowings that would have occurred, would have made the strata almost unrecognizable. Water erosion would have carved it into hills and valleys, some of which would have refilled. It's the extreme rarity of the findings you cite and the lack of erosion that is evidence that they were laid down rather quickly and.
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Then why are YOU even talking about science? Are you a scientist?
Yes.
Except that the owners of the burrows are often found fossilized within those burrows and terrestrial animals have distinctive burrows because of the nature of tunneling in air vs. tunneling underwater.
There may be layers that predate the flood and layers that occurred afterwards.
The former means the world is a lot older than allowed by YECs and the latter indicates that a lot more time has passed since the flood than YECs can account for. Not to mention there is no geological evidence for a single global flood anywhere.
So am I.
Cool new term (at least to me): Carbon chauvinism
If I may....
Virtually all "kinds" of critter are variations on some theme or the other.
Bear with me a moment for a thought experiment...
Cats, lions, cheetahs, leopards, tigers for instance are variations on the cattish theme. Let us start with a house cat and call it Proto-cat. Someone drops a bunch of uwanted Proto-cat kittens on an otherwise cat free island. The island has mice, birds, rabbits, trees and various plants.
Some of the Proto-kittens come up with a nifty pounce technique that nets them a great supply of delicious mice. When the young mama proto-cats take their young hunting, they learn pounce techniques. An odd mutation occurs that gives some of the population of pouncers tufted ears. Another occurs that enlarges the ear and enhances the ability to hear mouse scurrying feet. And, yet another occurs that shortens some of their tails.
Meanwhile.. the rest of the proto-cats eat whatever doesn't escape fast enough, but the mouse supply is diminishing because of the pouncers.
A pounce mutation occurs here, too, but there it doesn't last long because the other group of pouncer-cats is already more efficient due to those new ears. A whole lot of other mutations occur, but they don't have any effect on survival, like a pale stripe on the tails. Or they are damaging, which happens in both populations, pruning them a bit.
Can you see where this is going?
In the real world something like this can be seen in what is called ring-species.
If you want to follow up on this try:
http://www.actionbioscience.org/evolution/irwin.html
Why is it that folks who bloviate so much about intelligence always wind up reducing themselves to using threats instead of arguments? Threats are what Nazis and Communists use to change minds. Sounds more like Satan than God to me.
Birds of a feather don't breed together
by Carl Wieland
The fascinating phenomenon known as ‘ring species’ is sometimes quite incorrectly used to ‘prove’ evolution. The classic example is as follows.
In Britain, the herring gull is clearly a different species from the lesser black-backed gull. Not only can they be easily told apart, but apparently they never interbreed, even though they may inhabit the same areas. By the usual biological definition, they are therefore technically different species.
However, as you go westward around the top half of the globe to North America and study the herring gull population, an interesting fact emerges. The gulls become more like black-backed gulls, and less like herring gulls, even though they can still interbreed with herring gulls from Britain.
Now go still further via Alaska and then into Siberia (see map page 12). The further west you go, the more each successive population becomes less like a herring gull and more like the black-backed.
At every step along the way, each population is able to interbreed with those you studied just before you moved further west. Therefore, you are never technically dealing with separate species. Until, that is, you continue your journey into Europe and back to Britain, where you find that the lesser black-backed gulls there ‘are actually the other end of a ring that started out as herring gulls. At every stage around the ring, the birds are sufficiently similar to their neighbours to interbreed with them.’1 Yet when the ends of the ring meet, the two do not interbreed and so are for all intents and purposes separate species.
Evolution?
It is clear from such examples that species are not fixed and unchanging, and that two apparently different species may in fact be genetically related. New species (as man defines them) can form. The herring gull and the lesser black-backed gull could not have been initially created as two separate groups reproducing only after their kind, or else they would not be joined by a chain of interbreeding intermediates.
There are also observations of other wild populations from which a reasonable person must infer that certain very similar species did indeed share the same ancestor, even though there is no complete ‘ring’.
Many have been misled into thinking this is evidence for evolution and against biblical creation. However, some thought reveals otherwise. The key to understanding this is to consider the vast amounts of complex information in all living things, coding for functionally useful structures and processes.
Creation as described in the book of Genesis implies that virtually all the genetic information in today’s world was present in the beginning, contained in separate populations (the original created kinds).
This information would not be expected to increase, but could decrease with time—in other words, any genetic changes would be expected to be informationally downhill.
Evolution (in the normal meaning of the word) implies on the other hand that a single cell has become people, pelicans and palm trees. If true, then this is an uphill process—involving a massive increase of information.2
Change—but what sort?
The formation of new species actually fits the creation model very comfortably. The wolf, the dingo and the coyote are all regarded as separate species. However, they (perhaps along with several other species) almost certainly ‘split off from an original pair on the Ark—a species representing the surviving information of one created kind. Is there evidence that this can happen, and that it can happen without adding new information, that is, within the limits of the information already present at creation?
A ‘mongrel’ dog population can be ‘split’ into separate sub-groups, the varieties of domestic dog (breeders can isolate portions of the total information into populations which do not contain some other portions of that information). This sort of variation does not add any new information. On the contrary, it is genetically downhill. It involves a reduction of the information in each of the descendant populations compared to the ancestral one. Thus, a population of pampered lap-dogs has less genetic information/variability, from which nature or man can select further changes, than the more ‘wild’ population before evolution selection took place.
But is it conceivable that such change (which is obviously limited by the amount of information already present in the original kind) can extend to full, complete formation of separate species without any new information arising, without any new genes? (In other words, since evolution means lots of new, useful genes arising with time, can you have new species without any real evolution?)
Richard Lewontin is Alexander Agassiz Professor of Zoology at Harvard. In his book The Genetic Basis of Evolutionary Change he says there are instances in which ‘speciation and divergence of new full species’ have obviously occurred using ‘the available repertoire of genetic variants’,3 without requiring any ‘novelties by new mutation’. In other words, an ancestral species can split into other species within the limits of the information already present in that kind—just as creationists maintain must have happened.4
In the example we looked at, there is no reason to believe that the differences between the two gull species are the result of any new, more complex, functional genetic information not al-ready present in an ancestral, interbreeding gull population. Because there is no evidence of any such information-adding change, it is misleading to say this gives evidence of evolution, of even a little bit of the sort of change required to eventually turn a fish into a philosopher.
Ring species and similar examples actually highlight the great variety and rich information which must have been present in the original created kinds.5 They can be said to demonstrate evolution only to the gullible (pun intended).
References and footnotes
New Scientist, 5th June 1993, p. 37.
See C. Wieland, ‘Variation, Information and the Created Kind’, Creation Ex Nihilo Technical Journal, Vol. 5 Part I, 1991, pp. 42–47. The usual mechanism proposed is the cumulative selection of ‘uphill’ copying mistakes. However, the observational evidence for such information-adding mutations (as opposed to the occasional loss/defect giving survival value—e.g. eyeless fish in caves) does not appear to exist. On information-theoretical grounds one would expect them to be vanishingly rare if not non-existent.
Columbia University Press, 1974, p. 186. Lewontin refers to ‘new mutations’, as he believes that all existing variation came about by copying accidents (‘old mutations’) in the first place. However, that is belief, not observation. Note that a ‘downhill’ mutation can theoretically cause a reproductive barrier (and speciation) without adding any new, functional information.
For evidence that this can happen very rapidly, see ‘Darwin’s finches—evidence of rapid post-Flood migration’, Creation magazine Vol. l4 No. 3, June–August 1992, pp. 22–23.
It requires enormous amounts of variation to be already present for selection to result in ‘new’ types. A farmer cannot select for bigger eggs from his hens unless the information for this is already in the genes of some of them. Note that the common ancestor of these two gull species was likely already split off from (and genetically depleted compared to) the original kind.
Try selective pressure as the "guiding hand."
IOW evolution, only it all happened after the flood.
I'm not sure why you think it is necessary for a mutation to create genetic deletion.
Some mutations represent duplication of DNA sequences (CAG -> CAGCAG), some represent inversions(CAG -> GAC), some represent changes in the sequence itself (CAG -> GCA), not to get into substitutions, viral insertions and the like.
Ignoring them completely works best.
If you can't dazzle them with brilliance or baffle them with bovine fecal matter, threaten them with death and/or destruction. It works for Islamists.
But the guiding hand is invisible. And as any good socialist will tell you, the invisible hand doesn't work.
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