Darwin's mystery explained

Jul 14, 2009

The appearance of many species of flowering plants on Earth, and especially their relatively rapid dissemination during the Cretaceous (approximately 100 million years ago) can be attributed to their capacity to transform the world to their own needs. In an article in Ecology Letters, Wageningen (The Netherlands) ecologists Frank Berendse and Marten Scheffer postulate that flowering plants changed the conditions during the Cretaceous period to suit themselves. The researchers have consequently provided an entirely new explanation for what Charles Darwin considered to be one of the greatest mysteries with which he was confronted.

During the Cretaceous, the Earth's surface underwent one of its greatest changes in vegetation composition, a change which also took place with unprecedented speed. Frank Berendse (Professor of Nature Conservation and Plant Ecology), and Marten Scheffer, (Professor of Aquatic Ecology), both at Wageningen University, wanted to understand how this happened. They looked for the explanation in a totally unconventional direction.

Before the early Cretaceous, the vegetation consisted primarily of gymnosperms and ferns. These plants were largely replaced by an entirely new group of plants: the angiosperms (). During the early Cretaceous - approximately 125 million years ago - the first flowering plants evolved. Soon thereafter, the gymnosperms in the tropics were replaced almost entirely by the angiosperms. And by the end of the Cretaceous (65 million years ago), the empire of the flowering plants had become definitively established in much of the rest of the world. The gymnosperms continued to exist only in the far north - which is the case even today.

The rapid increase in the fantastic diversity of flowering plants - linked to their rapid conquest of the Earth - was one of the greatest puzzles faced by Charles Darwin. In a letter to Joseph Hooker dated 22 July 1879, he referred to an "abominable mystery". The great diversity of fossil flowering plants from the late Cretaceous, while there were virtually no fossils known from the early Cretaceous, appeared to be completely in conflict with his vision that the emergence of new species could only take place very gradually.

The big question was how this massive change could have taken place with such unprecedented speed. Was it because - just before the Cretaceous - that the big Sauropods were forced out by the much smaller Ornithischian dinosaurs, which then systematically ate all the seedlings of the gymnosperms? Or was it because the flowering plants could evolve simultaneously with many insect species that could pollinate their flowers?

According to Berendse and Scheffer, we must think in a totally different direction. They postulate that the flowering plants were able to change the world to suit their own needs. They grew more rapidly and therefore required more nutrients. In a world that was poor in nutrients and was entirely dominated by the gymnosperms, that kept the soil poor - with their poorly degradable litter - flowering plants had great difficulties to establish. But at some locations where the gymnosperms had temporarily disappeared, for example due to floods, fires or storms, the angiosperms could increase so  that they were capable of improving their own conditions with their easily degradable litter.

According to the theory of Berendse and Scheffer, this led to positive feedback; as a result, the flowering plants could increase even more rapidly and were capable of replacing the angiosperms in much of the world. Ultimately, the improved edibility of the leaves and fruits of the flowering plants led to a tremendous increase in the number of plant eaters on the Earth, which opened the way to the rapid evolution of mammals, and finally to the appearance of humans.

Provided by Wageningen University

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DonR
not rated yet Jul 14, 2009
"Darwin's mystery explained"

That title would suggest a definitive explanation, or at least one that's built on more than just an idea gleaned from early distribution of angiosperms. The study is little more than an idea. The title of this article is quite misleading.

It should probably read something like "Possible Explanation for Darwin's Mystery".
smiffy
1 / 5 (1) Jul 15, 2009
It's not even a robust idea. Angiosperms do not as a rule increase the fertility of the soil. They can only put back in the form of degradable litter what they've managed to take out in the first place.

Unless the first angiosperms had nitrogen-fixing colonies of bacteria like clover they wouldn't obviously improve the soil's fertlity. There's no reason to suppose that the fertlity-improving qualities of plants like clover were widespread amongst the early angiosperms or that the gymnosperms couldn't have also had these qualities.
Icester
1 / 5 (1) Jul 15, 2009
DonR and smiffy> You just don't get it. It's OK for evolution supporters to put forth unconfirmed, far-reaching hypotheses that only have the smallest germ of truth, but not creationists/intelligent design supporters. It's not a two way street.

I am not siding with either side. Just pointing out the fact that the finger pointing and accusations coming from evolution supporters are very hypocritical. If you are to put forth a new theory, then call it such. Not "mystery explained."

Sean_W
1 / 5 (2) Jul 15, 2009
If they grow faster and produce more biomass they will be increasing the carbon content of the soil. Even if they did not have symbiotic bacteria to fix nitrogen for them, such bacteria could still thrive in the increased soil couldn't they?

droid001
not rated yet Jul 15, 2009
Revolutionary idea!
This allows us to make the assumption that each of the species target is to create right conditions for higher forms of life.
We humans also pave the way for more complex form of life.
defunctdiety
3 / 5 (2) Jul 15, 2009
Angiosperms do not as a rule increase the fertility of the soil. They can only put back in the form of degradable litter what they've managed to take out in the first place.

Unless the first angiosperms had nitrogen-fixing colonies of bacteria like clover they wouldn't obviously improve the soil's fertlity.


Ah, but there's so much more to it than just the plant. Angio sperms attract insects, insects excrete, reproduce and die all around and on these plants they utilize in their life-history. Similarly, birds would be likely to excrete and die around angiosperms which are more attractive to them as food/habitat. Therefore the predators of those birds and insects will also excrete and die. So it's not only the plant that can "give back" to the soil, also everything that utilizes those plants and anything that utilizes the utilizers, etc. etc. ...
defunctdiety
not rated yet Jul 15, 2009
It's OK for evolution supporters to put forth unconfirmed, far-reaching hypotheses that only have the smallest germ of truth, but not creationists/intelligent design supporters.




1.) Scientific hypotheses are very different from straight up mysticism. The latter has no business in the realm of the former, and probably vice versa.



2.) It's not like the theorists wrote the copy for this web-site, they call it nothing more than a "theory" and "postulations" themselves.



3.) Like any media outlet, Physorg uses sensationalism to draw eyes (they do it A LOT).
smiffy
1 / 5 (1) Jul 18, 2009
birds would be likely to excrete and die around angiosperms which are more attractive to them as food/habitat.
Birds? Would you care to give an estimate of how many birds there were at the time of the rise of the angiosperms 100 million years ago? I'd say not many. And what possible reason do you have to think that birds would prefer angiosperms?
Angio sperms attract insects, insects excrete, reproduce and die all around and on these plants they utilize in their life-history.
The kind of insects that angiosperms would attract would have been flying insects, and the early birds were not nearly nimble enough to catch insects in flight. The very success of the flying insects means that they probably escaped heavy predation - unlike flightless insects which would be snapped up by small reptiles such as lizards, and flightless insects would not have had a particular preference for angiosperms.

What's more, flying insects would presumably feed off nectar which being mostly sugar would imply little excreta, unlike the excreta of worms for instance. Worms and deep-rooted plants do far more for soil fertility than bees and hoverflies.

Angiosperms became the successful widespread group they are today probably because of very efficient fertilisation of their seeds by insects, not fertilisation of the ground under them by insects.

Your hyped-up notions of modern ecology don't apply well to this aspect of the Cretacious.
seanpu
1 / 5 (1) Jul 19, 2009
Darwinian evolution cannot explain that part in evolutionary history because its not capable to do so. Darwinism is only a tweaking mechanism for those genes that are already in the animal/planet genome. It is impossible for Darwinism to create anything.

The only explanation for that period in history is the mass "upload" of genes from an external source, eg viruses, which would allow Darwinian evolution to start to work on these new programs.

Only that solution an explain the sudden acquisition of new characteristics and new genetics. We're still stuck in the mud with Darwin's theories as being the only possible solution to evolution. Darwin has been silently abandoned in unicellular research in favour of HGT and similar mechanisms.
defunctdiety
not rated yet Jul 20, 2009
It is impossible for Darwinism to create anything.


Sorry. Wrong. Ever heard of genetic mutation?
defunctdiety
not rated yet Jul 20, 2009
Your hyped-up notions of modern ecology don't apply well to this aspect of the Cretacious.


And your dumbed down scenario of closed circuit biological input/output was unacceptably limited and restrictive. I was merely point that out, never did I say this alone led to angiosperm's success.
mabarker
1 / 5 (2) Jul 20, 2009
I wonder how Berendse and Scheffer feel about Jansen's work at the U of T (Austin). Jansen talked of a biological 'big bang' of the angiosperms some "130 m.y.a." (if you actually 'believe in' all those millions of years). This explosion of plant diversity is still a floral mystery and Berendse and Scheffer's model doesn't begin to explain it. Angiosperms have always been angiosperms as the creation model describes. As for genetic mutations, I like what atheist Paul Ehrlich said in his 2000 book (p. 21), "Because mutations are randon relative to need and because organisms generally fit well into their environments, mutations are normally either neutral or harmful; only very rarely are they helpful - just as a random change made by poking a screwdriver into the guts of your computer will rarely improve its performance."
defunctdiety
not rated yet Jul 20, 2009
I forgot to respond to a few things:

Birds? Would you care to give an estimate... what possible reason do you have to think that birds would prefer angiosperms?


Hmm, well I'd say 99 species at the LEAST (realize this is in all likely hood but a percentage of what was actually there)...
http://en.wikiped...us_birds

But, I don't know what could POSSIBLY have made me think birds prefer angiosperms, they certainly don't eat tomatoes and strawberries and cherries and grapes and mulberries or any kind of fruit (angiosperms), no. Nor would they prey especially on bugs focused on getting nectar or burrowing into a fruit or stem or leaf, nah. Indeed angiosperms did not evolve for the very purpose of birds distributing their seeds over long distances in their feces (instant fertilizer), no, this is all just flights of fancy.

But okay, lizards and amphibians too will share space with angiosperms, space in which they will excrete and die. And it's not necessarily angiosperms they prefer, it's the insects that utilize the angiosperms. But here's an interesting fact, there are plants that mimic eggs... but oh well, I don't know what would possibly want to eat something that looks like an egg, and then later excrete that. Certainly not lizards, or later mammals.

The kind of insects that angiosperms would attract would have been flying insects... flightless insects would not have had a particular preference for angiosperms...


This has to be one of the most foolish generalized statements I've ever seen ventured on this website full of foolish ventures. Plants are utilized by all manner of insects, flightless and not. Maybe not a "particular" preference, but Angiosperms were a new niche that was exploited by all life forms. Including non-flying insects. Sorry sir, you are flat out wrong with your half-truths.

flying insects would presumably feed off nectar which being mostly sugar would imply little excreta...


Little excrement is still excrement, is still fertilizer. Dude stop trying to defend the indefensible, you obviously only have a fraction of a clue what you are talking about.

If you can come up with a legitimate reason why the relationships and interactions of "modern ecology" (lmfao, this is basic "common sense" ecology) don't apply here I'll leave you alone. But until such a time that you can explain to me why the plants and animals and the substrate they live in do not interact with and feed off each other, you had best just stay quiet because you are wrong and exposing yourself for a fool.
smiffy
not rated yet Jul 22, 2009

Birds? Would you care to give an estimate... what possible reason do you have to think that birds would prefer angiosperms?



Hmm, well I'd say 99 species at the LEAST (realize this is in all likely hood but a percentage of what was actually there)...
http://en.wikiped...us_birds
Well thank you for confirming that there were only a few species of birds that would have been capable of preferring the early angiosperms. While the fossil record won't be exhaustive many of the the birds in the reference you gave, which spanned the entire Cretacious period world-wide, would have developed after the angiosperms began their rise. Few, if any, of the birds that were around at that time would have been capable of catching flying insects, that the angiosperms would have preferentially attracted. Furthermore what few birds there were would have, if anything, preferred the seeds of the gymnosperms which are more easily accessible - in fact that may have been one of the reasons the gymnosperms declined. But even if there had been numerous birds the amount of input to soil fertility would have been scant compared to the input of other animals.
But, I don't know what could POSSIBLY have made me think birds prefer angiosperms, they certainly don't eat tomatoes and strawberries and cherries and grapes and mulberries or any kind of fruit (angiosperms), no.
I doubt that were any of these fruits available 100 million years ago. I doubt whether there were many fruits of any kind at that time. Again you have tried to transplant modern ecology to a distant, much different ecosysytem. You're still putting the cart before the horse. Fruit trees, a later angiosperm development, require rich soil, which the article is contending was not around at that time.
Indeed angiosperms did not evolve for the very purpose of birds distributing their seeds over long distances in their feces (instant fertilizer)
Angiosperms did co-evolve with birds because of the bird's seed distributing behaviour - but that is not fertilzation of the soil.
The kind of insects that angiosperms would attract would have been flying insects... flightless insects would not have had a particular preference for angiosperms...



This has to be one of the most foolish generalized statements I've ever seen ventured on this website full of foolish ventures. Plants are utilized by all manner of insects, flightless and not. Maybe not a "particular" preference, but Angiosperms were a new niche that was exploited by all life forms. Including non-flying insects. Sorry sir, you are flat out wrong with your half-truths.
You need to show that a "particular" preference exists in order to shore up your increasingly irrational and abusive rant.
Little excrement is still excrement, is still fertilizer. Dude stop trying to defend the indefensible, you obviously only have a fraction of a clue what you are talking about.
"Little" is not enough to explain the rapid rise of the angiosperms - it needs to be significant.

The rest of your post descends into bizarre insults that are frankly disgraceful.
HenisDov
1 / 5 (1) Jul 24, 2009
Of Flowers And Humans
Of Myopia In Evolution
entirely new explanation?


A. Darwin%u2019s Mystery Of Appearance Of Flowering Plants Explained
http://www.scienc...1621.htm

The researchers have consequently provided an entirely new explanation for what Charles Darwin considered to be one of the greatest mysteries with which he was confronted...


B. From "Life And Darwinism, Tomorrow's Comprehension"
http://www.the-sc...112.page

On The Origin And Tasks Of Brain Cells, "what all these new cells are good for"
http://www.the-sc...age#2822

Surprisingly...??? Human's genome continued survival mainly by modifying-controling its environment.

And AAAGAIN: For Nature genes are genes are genes. None are more or less important than the others. Genes and their take-offs, all Earth organisms, are temporary energy packages and the more of them there are the more enhanced is the biosphere, Earth's life, Earth's temporary storage of constrained energy. This is the origin, the archetype, of selected modes of survival.


C. Life is REALY simpler than they tell us in endless variations in AcademEnglish...


Dov Henis
(Comments From The 22nd Century)
Updated Life's Manifest May 2009
http://www.physfo...ic=14988&st=480&#entry412704
http://www.the-sc...age#2321

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