Racing Dinosaurs with Spoilers 60
PhilHibbs writes "The BBC is reporting a new theory - dinosaurs flapped their proto-wings to generate downforce for added traction when running up-hill. Another one to add to the many theories of the evolution of flight."
Insect flight (Score:4, Interesting)
It's an interesting theory, but I doubt a similar course could apply to birds. Their wings are covered with feathers, which are mostly just dead skin, and probably wouldn't absorb heat well. Plus birds are warm-blooded, and would have less need for sunning themselves.
Re:Insect flight (Score:4, Insightful)
Since evolution is still happening all around us, we can look at some of the "proto-wings" we see today and make some inferences.
We have squirrels that glide out of trees by stretching the skin between their legs.
We have snakes that do something similar.
We have flightless birds that still flap their wings when they run.
We have lizards that stretch membranes much like the flying squirrel. Some of them do it to glide, while others do it to control their temperature.
If feathers were only for flight, the flightless birds wouldn't have them, and flighted birds would only have them on their wings and tails. We use down for insulation in ski jackets for the same reason the goose made it in the first place.
A small, warm blooded dinosaur would need insulation. Insulation is lightweight for its bulk, so it would lower the density of the animal as a whole. This would protect the animal from falls, but it would also make it difficult to run, due to the air resistance overcoming the available traction.
Streamlining would be selected for. Small animals would experience higher Reynolds numbers (the air would seem thicker to them) and so flapping their feathered arms would get them more benefit than a larger animal would get.
It would not surprise me to find out that flight developed in several dinosaurs in parallel, given that we see it evolving in several quite different critters today (insects, reptiles, mammals, fish).
Your idea that flight developed as a side effect of temperature control mechanisms doesn't seem far-fetched to me at all. In fact, one might call it near-fletched, if one were a punning fellow.
Mod Parent Up (Score:2)
Re:Mod Parent Up (Score:2)
I did not mean to imply that this was my own idea.
It has been kicking around for a long time.
See this article [go.com] for instance.
Predator-prey ratios and other data have been used to show that some dinosaurs were warm blooded. A small wam blooded dinosaur would have needed some kind of insulation, since the heat is generated by the volume of the animal, but lost through the surface. The smaller the animal, the large the ratio of surface to volume, and thus the larger the heat loss.
Re:Insect flight (Score:1)
As some birds grew bigger, they no longer had the strength or wingspan to lift themselves off the ground, so they continued to evolve into today's ostriches. Or, flight was no longer needed because predators were scarce and food was plentiful in a certain area, so chickens stopped flying and evolved to put their energy into being fat, laying lots of eggs, and not spending much energy on maintaining wings.
Looking at current animals for ideas about evolution is great, but remember that groups of organims with great diversity, like birds, are all evolving; they are not stopping points. Kind of like how all dogs started from a generic wolf-like form and humans have bred them into Pomeranians and St. Bernards.
think on! -clan maclellan
Re:Insect flight (Score:2)
Actually, I wasn't forgetting ostriches at all.
They still flap their wings. So do roadrunners.
Flight is expensive. Some birds lose the ability not because of size, but because they no longer need to fly. The dodo comes to mind.
The fact or assumption that the ostrich used to fly is not the point. Look at how it uses its feathers and wings today, and ask yourself if it would be better off without them. If not, then they could be a model for a dinosaur that later evolves into a bird.
Re:Insect flight (Score:2)
Flight feathers are something different.
The long, broad, and stiff feathers you see arising in deinonychosaurs and other maniraptors are NOT insulatory, at least, not insulatory as far as keeping the individual animal warm. However, we DO know that maniraptorans minded their nests, often sitting on the nest to keep the eggs warm (fossils of nesting oviraptorids from Mongolia and troodontids from Montana prove that for at least some species). With the manner that they seem to hold their arms in such a nesting position, protoflight feather would be covering the nest, lending to the insulation of the nest. Keep the eggs warmer, you have fewer young that die in the egg, and an evolutionary edge. From these elongated feathers, you may have some of the smaller dinosaurs start gliding and eventually end up with flight.
Another possibility is as display. We know a lot of maniraptors were at least marginally social and some were much more social (such as Deinonychus). The originally nonfunctional feathers could easily have served as courtship displays. Once again, what was originally NOT a flight mechanism then found use as a gliding and then flight mechanism when other structures formed.
A third possibility is that feathers acted to help small maniraptors to trap prey. Maniraptors probably relied on their arms and long fingers (and large claws) to catch prey items. Stiff quills might have added a maginally netlike structure that could have given that extra edge on competitors. Eventually, once again, this structure evolved for something else becomes useful for flight and further develops.
I'd actually be less surprised to learn that most maniraptorans are descendants of flying dinosaurs that lost their ability to fly. Too many structures that otherwise don't make sense. Reversed hallux. Certain structures of the feathers, overly-long arms, etc.
Also, don't mistake gliding for true powered flight. Gliding has evolved countless times (especially in vertebrates). True powered flight has not. Birds, pterosaurs, bats, and insects are the only organisms I can think of that have evolved true powered flight. Whether the flight mechanism has wavered between functional and nonfunctional (as it may have been in early flying dinosaurs/birds) is a totally different question than how many times it independantly arose.
it's all lies (Score:2, Funny)
Even reputable news sources [theonion.com] agree.
P.S. First post.
Re:it's all lies (Score:3, Funny)
Evolution is just as much a religion as Creationism.
Saying that over and over doesn't make it true.
Re:it's all lies (OT) (Score:1)
religion noun:
a cause, principle, or system of beliefs held to with ardor and faith
Since you can't prove evolution as the beginning of life (at least until someone invents a time machine, and how likely is that?), you're holding it in faith. How is that any different from believing in creation?
Re:it's all lies (OT) (Score:2)
Re:it's all lies (OT) (Score:2)
Since you can't prove evolution as the beginning of life
Since evolution doesn't attempt to explain the beginning of life, that statement is pointless.
Re:it's all lies (Score:3, Interesting)
There's more evidence towards evolution (cosmic and biologic) than towards creationism, that's for sure. So no, it's not as much of a religion.
If you need evidence about the hydrogen stuff, go do a degree in physics (at a decent university). I just did, and trust me that's not mere fantasy. As for the biological evolution, darwinian selection works fine in every other system... why shouldn't it work in biology?
Daniel
Re:it's all lies (Score:3, Interesting)
To you, perhaps. Unfortunately, both sides sometimes overlook the details of evolutionary theory. Evolution is best described, IMO, as two different things and they often get lumped together. First there is the phenomena of evolution, that offsprint inherit the traits of their parents (or parent in the case of asexual reproduction), and these traits have the ability to change over time, for better or worse. Secondly, there is the theory of evolution, which is the entire lump of theories/hypotheses that describe the path by which we came to be over 5 billion or so years.
The idea that organisms can "evolve", as described in the first case is well understood and generally taken as fact, since we now have a pretty good understanding for the molecular basis of this macroscopic observation (DNA->Protein, central dogma, etc). If creationists insist on condemning this as not fact (even the vatican has accepted it), they will only further hurt their arguments.
I'm not an expert on the second case, but I believe quite strongly that knowledge of the first case is compelling evidence for the second, especially in light of all the other piles of observational evidence and the historical record that is available.
-Sean
Re:it's all lies (Score:3, Informative)
Logically, evidence for the first case is not evidence for the second. It's a bit like any inductive proof, proving for n still leaves the proof for n+1. In evolution, we know micro-evolutionary changes through DNA mutations are possible. But that the process of mutations can be extended indefinitely back to a common ancestor is a seperate issue.
The only historical evidence available to support the second case is from the fossil record, which even www.talkorigins.org considers the 'weakest' proof for evolution. Our other observational evidence lies mostly towards 'mountains' of evidence for the first case, but only quite limited evidence for the second. Check www.talkorigins.org's list of evidences of macro-evolution for a decent listing.
Re:it's all lies (Score:3, Insightful)
Like I said, I'm not an expert on evidence for the common ancestor theories. That said, while microchanges and adaptions through mutation may not by itself be evidence enough to satisfy, when combined with the DNA/RNA/Protein sequence evidence , it becomes rather compelling, IMO. (once again, I'm a bit out of my area)
It comes down to two options, an intelligent agent (god, aliens, etc) could have created the species' with DNA sequences that fit a mutational model quite well, or every organism could have a common ancestor and these sequences evolved naturally through mutation. If an intelligent agent created the species, why would it engineer the DNA/RNA/Protein sequences such that they looked exactly like they would if they got that way by eons of mutation? Occam's razor would tell you that natural evolution of those sequences is a far, far simpler and more likely explanation, especially in light of the fact that microchanges happen spontaneously and are commonly observed in the laboratory.
-Sean
Re:it's all lies (Score:2, Insightful)
Although this depends on one's interpretation of similarities in DNA between living creatures. On a biological level creatures use similar organs to perform similar functions. The same is logically the case on the molecular level. DNA in similar creatures would be expected to be similar. The molecular evidence, from what I know is no more compelling than morphological based phylogenetic trees. That is to say, molecular evidence shows no inidication of missing links existance. That mutations back to a common ancestor can be thought up is one matter, but the feasability of those mutational, in between forms is still as in question as before.
If an intelligent agent created the species, why would it engineer the DNA/RNA/Protein sequences such that they looked exactly like they would if they got that way by eons of mutation?
Well, it's pretty early still in our understanding of DNA but I'd hazard they wouldn't. Furthermore though, I'm unconvinced that they do appear to look like they have evolved over eons. All the evidence I've seen and found(and I've looked, please show me any you think is compelling), falls into two categories. DNA that looks like it has evolved over a short time within species, or junk DNA we don't yet know the purpose of and we assume similarities in this junk DNA between species is evidence of common descent. I still believe we'll find functional reasons for those similarities. The common descent interpretation is just that, an interpretation. I personally see the evidence and take a different view of what it represents.
Occam's razor would tell you that natural evolution of those sequences is a far, far simpler and more likely explanation, especially in light of the fact that microchanges happen spontaneously and are commonly observed in the laboratory.
Occam's razor is not a cure all magic wand though. It can as easily be turned around to say abiogenesis seems highly improbable(by currently known methods), and depending on how probable you believe God's existance is, one could say God is more likely to exist than a natural method by which abiogenesis occured.
Re:it's all lies (Score:2)
All of your points are well taken. As to the one above, the rate at which sequences change is a PhD in itself, and looking for a good molecular clock (sequences that change on the order of time that you are trying to look) is a challenging problem. I think the work by Gary Olson and Carl Woese (at UIllinois many years ago) on ribosomal RNA sequences is the most interesting. There are databases of these sequences available here [rug.ac.be] and here [msu.edu] and many many papers discussing their implications. Including the prediction of a third cell type based on rna sequences, the archaens....
Cheers,
-Sean
Re:it's all lies (Score:2)
The conclusion of that paper was pretty much like all other molecular phyogenies I've found. Still inconclusive and raising questions about our former ideas about how the phylogeny should have looked. It's this trend of conflicting findings, that would be expected if our common descent assumption is wrong, that continue to make me think our evidence for common descent is not compelling.
As I find other examples that pertain I'll post them. If you have any in particular you've seen just let me know, thanks again.
Re:it's all lies (Score:2)
Years ago, penicillin used to be able to kill just about everything that you could be infected with. However, mutant strains of common bacteria that were resistant to penicillin survived, while the strains that hadn't evolved to resist penicillin died off. There's natural selection in action for you. It's still happening: drug companies are developing new antibiotics every day to combat the mutant strains of bacteria and viruses that have become resistant to yesterday's antibiotics.
As for the evolution part: take some kind of bacteria that causes people to get sick. There are always going to be a few of each kind that mutate. That's all evolution really is, IIRC: mutation and heredity via DNA.
Some of the sun's radiation passes through a bacterium, and slightly alters its DNA. This bacterium then divides. Now, if the genetic mutation that the sun caused is beneficial, then natural selection means that it has a greater chance to survive than its non-mutated brethren. If the mutation is detrimental, then the new strain will soon die off.
whacky Americans (Score:1, Offtopic)
There aren't too many places in the English speaking world where that comment would get a "-1 flamebait".
I guess American Christian Fundamentalism and Islam aren't that far apart after all.
I think about the only difference is that Islam proscribes family photographs.
Evolution is just as much a religion as Creationism.
It just gets better.
I'm heading for -1 Offtopic or -1 Flambait too I guess.
Re:whacky Americans (Score:2)
I guess it's a sign of the times.
Re:whacky Americans (Score:1)
Well that and I don't have any mod points.
Re:whacky Americans (Score:1)
Daniel
Re:it's all lies (Score:1)
That (Score:1)
Re:That (Score:2)
Learn some physics (Score:1)
- has to be the most rediculous theory I have EVER heard. Extra downforce for running uphill??
The extra downforce increases the normal force exerted from the ground on the bird. Friction is proportional to the normal force, and thus provides more traction to allow the bird to run up the slope (rather than allowing the bird to slide back down the slope).Think about it... imagine you have a slope with a block that kept sliding down it. If you push down on the block, you can prevent the block from sliding down.
Learn some physics before you make comments like that. :-P
Re:Learn some physics (Score:1)
It's not the physics... (Score:2)
Yeah, that's great. Are you really agreeing with the theory that dino's ran uphill SO MUCH that evolution picked the ones that would do it BETTER than the other ones?
Maybe if they had to run uphill so much, they really got 'wings' to float back down ;) It was a form of protection, see. They'd let a 'sharp-tooth' chase them up a cliff, they would jump off and float to the ground, while the 'sharp-tooth' fell to his death.
Yeah, that's it ;) Where's my prize?
Re:It's not the physics... (Score:1)
I said nothing about whether or not I agree with the theory. I was merely correcting his misconception that the downward force doesn't help the bird in moving up the slope. Whether or not this actually helped evolutionarily is another question.
Seems a bit weaker... (Score:2)
Re:Seems a bit weaker... (Score:2)
lift vs downforce, flapping vs climbing (Score:2, Interesting)
Maybe the important component was forward force rather than footward force, though by bending forward more a small component could be directed footward while most was directed in the direction of motion to get away from the predator.
The article also did not explain why it wouldn't be more efficient for the creature to use their front legs for additional ground contact, and evolve into a squirrel or lemur. If their arms were too short, they probably wouldn't provide significant force by flapping.
While arms are good for climbing stiff surfaces like trees, they might be less usful for climbing loose surfaces like sand dunes, or dead-leaf-covered hills in temperate climates, or mud swamps. (If it was dusty, maybe part of the strategy is to blow/flap dust rearward toward the predator?:) Any clues on what the environment was like where these creatures lived?
Re:lift vs downforce, flapping vs climbing (Score:2)
Actually, I want claws. (Score:1)
1) it probably is more efficient
a) don't need the extra muscel mass to flap wings. b) don't need the extra muscel mass to counteract the downward force of the wings. 2) its harder to negotiate around branches if you actaully had wings
All in all, this is a silly hypothesis. Ever see woodpeckers, flapping their wings to counteract the force that they are pecking the tree with. Just in case you haven't seen a woodpecker, they will hang on to any portion of the tree with their claws, and peck (without flapping their wings
Now that I have stated my opions with my observations, do you know of any modern animals that have evolved to use a spoiler.
Re:Actually, I want claws. (Score:2)
Are you saying that birds aren't modern animals?
The real question is... (Score:5, Funny)
The Dino Dance? (Score:2)
Does this mean that the next time I'm forced to do that God-awful "Chicken Dance" at a wedding that I can at least take some solace in the fact that I'm actually doing "The Raptor Dance" or "The Tyrannosaurus Rex Dance"?
GMD
Does that mean... (Score:2)
science without data. (Score:2, Interesting)
Thus is the beauty of doing science without data. Hypotheses are uncontrained.
At the far extreme:
Aliens planted diosaurs... disprove it?
Re:science without data. (Score:1)
New, Novel, and Lousey (Score:1)
If this were true then... (Score:2)
Likewise the era of pre-marsupial when ground birds ruled in the southern americas ought to show skeleton optimized for traction since none of these flew, yet they were predators like dinasours.
why dont cheetas have wings?
Racing with spoilers (Score:2)
The Fast and the Jurassic (Score:1)
Shit, now I've jinxed it, its going to happen.
Re: evolution vs. creation (Score:2)
> The biggest problem I see with the whole evolution thing is that the more we dig, the more find weirder and weirder species that seem to have nothing to do with what's around today.
That's completely compatible with the theory of evolution. It doesn't predict what we will find in detail, but what it predicts at the higher level is that the tree of life will be very bushy, with some things closely related and others only very, very distantly related.
> Doesn't the evolution theory predict that we should be finding a lot of intermediate forms of present day species?
The theory doesn't predict that we will find anything. There are lots of problems with finding the remains of stuff that has been dead for thousands, millions, or billions of years. Consider the problem of finding the remains of your own ancestors: you could probably take me straight to where grandpa and grandma are buried, but if you go back 5, 10, 50, or 100 generations you would be less and less likely to actually be able to find anything even if you made a full-time job of looking for it.
But as it happens, over the past couple of centuries we have found lots of intermediate forms. We have even identified several species that are thought to be on our side of the family tree since the split with our nearest living kin, the chimps.
> Is there even a single species where we can find a complete chain of intermediate forms between it and a previous species that it evolved from?
That's very problematic, because there's no way of actually knowing how many intermediates existed between two species. Sometimes you can make some very general predictions, but for the details you just have to dig and see what you find.
BTW, the joke on talk.origins is that there will always be "missing links", because every time you find one you create two more -- one on each side of the one you just found!
Re: evolution vs. creation (Score:1)
know of are all so vastly different from one another, that
there is little evidence of common ancestery. The differences
between say, models of cars, something we create, look a
lot closer to a chain of random mutation adaptions than the
various fosils we find. Extrodinary theories require extrodinary
proof. Evolution is a quaint hypothesis, but after a century of
research by scientist trying desperately to find evidence to
support the theory, I've yet to see a single pair of fossils that
are close enough to one another to be a single mutation apart,
but are not within normal variation of a single species.
It's either normal variation within a species, or something
totaly unique. We should see all kinds of creatures and
evidence of past creatures that are similar, with relatively
smooth transitions from one form to another. The just isn't any
evidence of that.
Re: evolution vs. creation (Score:3, Insightful)
> I've yet to see a single pair of fossils that
are close enough to one another to be a single mutation apart
You and your parents are several mutations apart. You won't find that minimal quantum jump in the fossil record.
> We should see all kinds of creatures and
evidence of past creatures that are similar, with relatively smooth transitions from one form to another. The just isn't any evidence of that.
No one is going to make you believe the results of scientific enquiry if you don't want to, but if you want to sound like an informed critic you're going to have to get informed first. There is absolutely nothing in the theory of evolution that implies that we should have the collection of fossils you are demanding to see.
Re:evolution vs. creation (Score:1)
In addition to the fossil record, one can look to living species to look for evidence. In the US, the Red Tailed Hawk shows several coloration morphs. Black ducks and Mallards can interbreed.
People seem to have problems with the idea that natural selection can ever find new solutions to problems through mutation/selection. IMO, the features that make it possible include: the power that genetics has for searching for solutions to complex problems, the length of time represented by millions of years, the multiplicative factor of having millions of individuals and the adaptability that individuals display to changes. This last allows a mutation that, by itself might be a disadvantage, to have a better chance of combining with other changes to become an advantage.
Most of evolution has to do with adaptations to new environmental conditions. The genome addresses this problem by retaining old discarded solutions to past problems. This allows relativly rapid changes.
At this point, the human animal is at risk from only one macroscopic species - other humans. That does not mean that humans will stop evolving. However, immortalitiy could change that.