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?"
You can observe the curvature of space/time? What is the mechanism that causes gravity? Gravity is simply a name given to the observable phenomenon that two masses will attract each other. Speciation is the term given to the observable phenomenon that a subpopulation of an organism can change to the point where it can no longer breed with the original population. This has in fact been observed. Much like the case with gravity, it is the mechanisms that aren't fully understood.
Laws are not absolutes. Neither are constants. Laws are descriptions of a regularity found in observations. Laws can be demonstrated to be incomplete or incorrect in some circumstances (Think of Newton's Law of Universal Gravitation for an example.) Constants are measured values of an important parameter. This measured value can change as technological advances are made (Think of the speed of light and how this measured value has changed through history). The primary importance of constants is typically the role they play in laws and theories. (For example relativity theory gives the importance to the speed of light, quantum theory gives importance to Planck's constant.) If theories or laws that use a constant need to be revised, different constants will come into play.
My response was to a post about the Intelligent Designer's eraser and was therefore appropriate.
Threats are also used by our own justice systems to get people to obey the law. And not threats but rather warnings are used by God to remind people that there is indeed consequences of sin and they aren't pretty.
The whole physical death and sickness thing is to teach us about spiritual death, in order to get us to avoid it.
You may not like being reminded that there are consequences to sin, but there are.
Because the tendency is toward extinction except where biodiversity is sufficient to support hightly specialized niche organisms.
The Robber fly exists only in the Canary islands because it died out elsewhere due to lack of biodiversity, not because it was formed because of abundant biodiversity.
High biodiversity generally indicates an abundance of resources. An abundance of resources means competition for survival is low.
You see, it all depends on your initial assumptions. The follow up studies would now call for experiments to substantiate one hypothesis over the other.
Of course, that won't happen because of paradigm lock.
The problem with the arguments given for irreducible systems is that you have to deal with random probabilities; selection pressures don't come into play. When you remove the weighting from the probabilities (natural selection), the math becomes very damning.
Hmm. Lack of grants vs. really, really fun lab work.
If you think it is a sin not to agree with you, then welcome to the wonderful world of mental illness.
Unless the designer designed to allow for extinction. It's silly to assign your idea of perfect design to someone else and then accept or reject a hypothesis of design based on that prejudice.
"...and scientists speculate..."Meanwhile, in a parallel universe, your parallel self (the one with the beard) posted this...
---
"The researchers think..."
---
"This new theory..."
---
"It is thought..."
---
"...still not fully understood by scientists..."
---
"Therefore, they speculate,..."
---
"...if it stands further scrutiny."All this is is speculative guesswork. Yawn.
"...and scientists assert..."
---
"The researchers know..."
---
"This new fact..."
---
"It is known..."
---
"...fully understood by scientists..."
---
"Therefore, they insist,..."
---
"...it WILL withstand further scrutiny."
All this is is arrogant dogmatism. Yawn.
The burrows are few and far between, they are not what you would expect if those strata were laid down over eons.
The flood lasted a year. The land may have become exposed at various times allowing both fossilized raindrops, tracks and burrows. The scarcity of such burrows still speaks volumes for anyone willing to see.
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.
Given what assumptions? Neither the former nor the latter necessarily implies what you think it does.
Did I say that?
Now I understand your problem.
You assume that these insertions, inversions, deletions etc. diminish the informtion.
Not correct. Although it is counter intuitive, they don't.
Here's a for instance. The article describes an inversion in Europeans that is associated with both increased fertility and greater longevity:
http://www.separationsnow.com/basehtml/SepH/1,1353,6-1-1-0-0-news_detail-0-1926,00.html
Something about evolution causes you to make dire warnings about the state of people's souls, as if your partular understanding of God gives you some special insight.
Perhaps you are uncomfortable about being called on it.
I notice you never ask if fellow FReepers are kind to their children or spouses, or whether they volunteer their time to help the less fortunate. You seem to be focused on whether people agree with your theology.
Except that "the whole world was covered" to a depth of something like 30 to 45 feet. Even if "the land may have become exposed at various times" the critters that would make such tracks would all have drowned in the interim. The only survivors, according to the Bible, were those carried aboard the Ark.
As usual, Carl Wieland both completely misses the point, and misrepresents the subject he's attempting to critique.
Please do not post your false presumptions as if they were fact. You would do well to learn the different between your fantasies and reality.
The flood lasted a year. The land may have become exposed at various times allowing both fossilized raindrops, tracks and burrows. The scarcity of such burrows still speaks volumes for anyone willing to see.
Again, please stop posting falsehoods. As is too often the case, you have no real knowledge of the actual state of the evidence, and instead of making the effort of learning about it, you just post what you *imagine* it "must" be like. Stop it.
The mechanism is unknown and the process has never been observed, but scientists claim to know that it's true.
Oh, puh-leaze.... The astute reader will note that Aquinasfan is unable to understand the vast difference between "not *fully* understood" and "unknown".
Furthermore, please stop telling falsehoods -- the process most certainly *has* been observed.
And scientists accuse Christians of dogmatism?
When the shoe fits, sure. Furthermore, I'm happy to accuse you in particular of really poor reading comprehension.
Consult any good paleontology text. A good one is available free online here: "Paleobiology: A Synthesis", Edited by Derek Briggs and Peter Crowther. It's a bit out of date (1990), but hey, it's free.
Second, the location.
Earth.
Third, the timing.
Over the past four billion years. For specifics, I again direct you to a paleontology text.
I see... And what excuse do you use to hand-wave away the DNA evidence of historical origins?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.