Posted on 12/29/2013 12:13:31 PM PST by SeekAndFind
A new study has found that species living together are not forced to evolve differently to avoid competing with each other, challenging a theory that has held since Darwin's Origin of Species.
By focusing on ovenbirds, one of the most diverse bird families in the world, the Oxford University-led team conducted the most in-depth analysis yet of the processes causing species differences to evolve.
They found that although bird species occurring together were consistently more different than species living apart, this was simply an artefact of species being old by the time they meet. In fact, once variation in the age of species was accounted for, coexisting species were actually more similar than species evolving separately, opposite to Darwin's view which remains widely-held today.
'It's not so much a case of Darwin being wrong, as there is no shortage of evidence for competition driving divergent evolution in some very young lineages,' said Dr Joe Tobias of Oxford University's Department of Zoology, who led the study. 'But we found no evidence that this process explains differences across a much larger sample of species.
'The reason seems to be linked to the way new species originate in animals, which almost always requires a period of geographic separation. By using genetic techniques to establish the age of lineages, we found that most ovenbird species only meet their closest relatives several million years after they separated from a common ancestor. This gives them plenty of time to develop differences by evolving separately.'
The study, published in Nature, compared the beaks, legs and songs of over 90% of ovenbird species. To tackle the huge challenge of sequencing genes and taking measurements, Oxford University scientists were joined by colleagues at Lund University (Sweden), Louisiana State University, Tulane University (New Orleans) and the American Museum of Natural History (New York).
Although species living together had beaks and legs that were no more different than those of species living apart, the most surprising discovery was that they had songs that were more similar. This challenges some longstanding ideas because the standard view for the last century has been that bird species living together would need to evolve different songs to avoid confusion.
'Looking at the bigger picture, 'be different or die' doesn't appear to explain evolution,' said Dr Tobias. 'Ovenbird species use a wide variety of beaks, from long and hooked to short and straight, but these differences appear to evolve when living in isolation, suggesting that competition is not the major driving force producing species differences. Instead, it seems to have the opposite effect in promoting the evolution of similar songs.
'The reasons for this are difficult to explain and require further study, but they may have something to do with the advantages of using the same 'language' in terms of similar aggressive or territorial signals. For instance, individuals of two closely related species with similar songs may benefit because they are able to defend territories and avoid harmful territorial contests not only against rivals of their own species but those in other species coexisting in the same places and competing for similar resources.'
'The real novelty of this research is that it takes the evolutionary age of species into account,' said Dr Nathalie Seddon of Oxford University's Department of Zoology, co-author of the study. 'A first glance at our data suggests the same patterns that Darwin had expected. It is only when accounting for the fact that species vary in age, and then comparing between lineages of similar age, that the picture changes.'
'These insights are the result of a hugely collaborative venture, and a good example of standing on the shoulders of giants. It took almost a decade to compile genetic sequences and trait measurements from 350 lineages of ovenbird. The song recordings were made in over twenty countries by numerous tropical ornithologists, including ourselves, and the museum material was based on specimens collected by hundreds of individuals stretching back to the famous British naturalist Alfred Russell Wallace in the 1860s.'
The research was funded by the Oxford University John Fell Fund, Queens College, Oxford, The Royal Society and the United States National Science Foundation.
>>I am saying TToE, as you put it, is not a theory because it is not falsifiable.<<
You are wrong.
My example stands. And it is only one.
Your example of the horse doesn’t stand. It might just be geological theory was wrong.
Let’s stay on that example. How would such a finding disprove TToE?
me neither.
How many fossils do think have been excavated in the last 200 years?
Billions, easily.
________
So, on average, 14,000 fossils per day, every day for 200 years have been excavated?
>>How would such a finding disprove TToE?<<
it would mean a species did NOT evolve at all and was NOT subject to stochasticism, which TToE says is not possible.
I think you are trolling, so we are done now.
That is until you learn science and not how to mimic knowing it. Your use of the completely wrong scientific terms should have clued me to your hidden agenda.
Have a great New Year.
The only ovenbirds I could think of offhand were chickens, turkeys, and ducks. I was amazed to learn that there are 350 species of ovenbirds.
Why so paranoid?
I am not trolling. I am making a point you find uncomfortable.
I come from a purely biological view point.
TToE is not falsifiable.
What scientific term are you saying I used wrongly?
And i will point out, you are the one getting upset and angry and talking about “sides”.
Things which "drive" evolution include government grants, conformity, yuppyism, herd instinct.....
What mental hash of "adapt or perish" is that?
Adapt or perish. Simple, true. For example, adapt to God's law, and build Western Civilization, or fail to adapt to it, and perish as countless civilizations have over the eons. Or in a mini ice age, adapt to the changed climate, or perish. Or say the Yellowstone Caldera blasts off and covers most of the continental US in ash -- we adapt to what environmental damage it wreaks, or we perish.
It isn't "survival of the fittest," as in survival of the most ruthless. It isn't "be different or die."
It's adapt, or perish. Change is a state of life. We adapt to it -- or perish.
ininnegan to freedumb2003: "So, on average, 14,000 fossils per day, every day for 200 years have been excavated?"
"Billions" is a bit high.
Tens-of-thousands would be more realistic.
All told, there are estimated to be circa eight million total species alive today.
Those known for certain include 6,000 each mammals & amphibians, 10,000 each birds & reptiles, over 30,000 fish, over a million invertebrates and around 300,000 plant species.
The average species is said to survive around a million years before it either goes extinct or evolves into a definably different species.
So by at least every million years, the earth sees nearly 100% turnover in its species inventory.
That means: if you examine fossils from a million years ago, nearly all the ancestors of today's critters are classified as different species.
There are very few-if-any million-year-old fossils of today's species, and by the time you've gone back a few million years, there are none.
Similar looking critters, sure: crocodiles come to mind.
But remember, the scientific definition of "species" is very concerned with the degree of difficulty different sub-species might have interbreeding.
When sub-species grow so different they can no longer readily interbreed, then they are re-classified as different "species".
So one of the great scientific enterprises today is careful DNA analyses of all the various breeds, sub-species, species, genera, etc. in order to determine the years from separation -- last common ancestor -- and what known fossils might correspond to them.
Point is: the fact that ancient crocodile fossils look similar to today's doesn't imply they were close enough genetically to theoretically interbreed.
So, FRiends, if you are counting data points, then known fossils would be in the tens of thousands range, and your billions of data points would come from DNA comparisons.
As for the question of whether Evolution Theory might ever be scientifically falsified, the answer is sure: in the same sense that Einstein's theories might someday be falsified -- possible but highly unlikely.
What's more likely is that, just as Einstein reduced Newton's laws to a category within a larger context, so Einstein's theories are even now being reduced to a mere scientific category within a larger context of... what?... strings or multi-verses? Things well beyond even our imaginations...
And such indeed might be the eventual fate of Evolution Theory, though as of today we've seen no evidence for that...
I'm still trying to figure out just what the definition of "troll" is.
Near as I can tell, a "troll" is defined as: somebody who gets the better of me in a disagreement, and a really nasty "troll" gloats over it.
Happily, neither of those activities is forbidden on Free Republic... ;-)
At this point, after 150 years, you can almost forget about falsifying basic evolution theory: descent with modifications, natural selection.
There's too much evidence supporting it.
What can and doubtless will happen is that new mechanisms for modification and selection will become better understood.
For examples, today's reports on the effects of occasional interbreeding between species, or even the ability of viruses to spread genetic code.
What these show is that "descent with modifications" may not always be 100% random.
Might science find evidence of other "non-random" modifications?
Sure, but that would not necessarily falsify evolution theory, only suggest that it might be more guided, less "random"...
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