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How Birds Lost Their Teeth
An anonymous reader writes A research team from the University of California, Riverside and Montclair State University, New Jersey, have found that the lack of teeth in all living birds can be traced back to a common ancestor who lived about 116 million years ago. From the article: "To solve this puzzle, the researchers used a recently created genome database that catalogues the genetic history of nearly all living bird orders--48 species in total. They were looking for two specific types of genes: one responsible for dentin, the substance that (mostly) makes up teeth, and another for the enamel that protects them. Upon finding these genes, researchers then located the mutations that deactivate them, and combed the fossil record to figure out when those mutations developed. They concluded that the loss of teeth and the development of the beak was a two-stage process, though the steps basically happened simultaneously. The paper states: 'In the first stage, tooth loss and partial beak development began on the anterior portion of both the upper and lower jaws. The second stage involved concurrent progression of tooth loss and beak development from the anterior portion of both jaws to the back of the rostrum.'"
Have you ever seen a bird brush and floss? I haven't.
No wonder they lost all of their teeth.
There was a book about this. It was called The Island of Doctor Moreau.
Do not look into laser with remaining eye.
It's superior if and only if you need to dig for grubs in dirt and wood with your mouth.
6005.99999 years ago, one of them flipped God the bird and so He did Smite them and lo their teeh were no more and there was lamentaion and suffering.
Also, beaks are much lighter than teeth, which was probably a significant factor.
Also also, if you're thinking about mammal teeth, you're probably imagining it wrong. One of the unique things about mammal teeth is their complexity relative to the other branches of the vertibrates. Studying mammal evolution has been described as an exercise in studying teeth.
It's thought this advanced tooth development went hand in hand with warm blooded development during the pre-mammal period as more adavanced, inerlocking teeth were requied to mash up food better for quicker digestion which was required for a faster metabolism.
Most reptile teeth look primitive by comparison. Except that simple teeth are easily replacable and so reptiles can regrow lost teeth much more easily (later on some mammals in the ungulates developed open roots for continuous growth which was useful for grazers, whereas others hae a large stock of teeth then starve to death when they run out). The specialisation makes these much harder.
It seems likely that birds did not have the great teeth for supporting warm blooded metabolisms, but rather the simple, robust general purpose teeth of other reptiles, so in this sense there were not losing nearly as much. They also solved the grinding problem in a different way, using a gizzard (this may well predate birds: crocs have gizzards as well and it is speculated that some dinosaurs did). As a result they were replacing the bit that grips and possibly does some initial cutting of food with a much more lightweight structure.
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The problem is you are not smart enough (no one is - except perhaps god) to understand all the intervening steps.
You don't 'give up' teeth, you get a mutation and are stuck with it. They are not making conscious decisions to evolve, that is just plain ignorance. If you can find a way to survive without the teeth, you continue on. Eventually you get another mutation, and maybe it evolves to take the place of something you lost.
Birds found a way to survive without teeth before they gained a beak. Possibly it was those rocks some birds swallow and use to grind up large chunks of food (I don't know when or if all do this).
Maybe teeth became a liability. People used to die from a rotten tooth, maybe there was an epidemic of bird tooth infecting microbes. It doesn't matter.
As for gender based on-single cell organism, you have that wrong also. Sex evolved from eating - the victim's genes survived inside the single cell that tried to eat it, and it's grew from there. At that point all those single celled life forms were hermaphrodite - they could eat or be eaten and their DNA would survive in the eater. Eventually, the hermaphroditic single celled life forms developed into two varieties - one that could eat and absorb the DNA (female) and the other that could be eaten and pass on their DNA (male).
Also there was no clear line between single celled life forms and multicelluar life forms. First came colonies that learned to cooperate but could also survive on their own.
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The gizzard came first. I remember reading about dinosaur fossils found with small, smoothed stones where a gizzard would be. It seems likely that the saurian ancestors of birds already had gizzards. They had tearing teeth but no chewing teeth and depended on the gizzard to break down their food.
They have the loss of teeth and the development of the beak, but where did the gizzard develop? They would not have been able to loose their teeth and develop a beak without one, and birds are the only animal (That I know of) that has one.
Plus gizzards are great when fried. ;)
According to Wikipedia, many reptiles including dinosaurs have/had gizzards.
Why give up teeth
Because as things changed and the years passed they became more of a hindrance than a help to birds (or their ancestors) and so those offspring born with fewer teeth, or smaller teeth, were better at surviving and having offspring.
how to convince your unborn offspring to do take it to the next step.
Why would any "convincing" be required? The offspring are likely to face the same challenges as their parents. If they've got traits that help them survive better than their peers - such as fewer or smaller teeth - then they'll pass these on to their offspring. Then, in turn, those offspring will be facing the same pressures again. So once again, among those offspring, those with fewer or smaller have a better chance at surviving than their brothers and sisters (and cousins).
You would expect these animals to be superior to us and make conscious decisions to change their DNA, to evolve
What animals are you talking about? No animal needs to make a conscious decision to evolve. It's already taken care of by inheritance and selection pressure.
As long as you've got a mechanism for children to be largely similar to but ever-so-slightly different from their parents, and a reason for some of those offspring to reproduce more successfully than others because of those differences, then evolution is inevitable.
systemd is Roko's Basilisk.
The problem with macro evolution is the inherent issues with the "in between" stages that are mostly useless, being neither good for one thing they are coming from or good for the thing they are changing into.
The example I use is Butterflies, which change from a crawling creature to one that flies, mid life. Incredible "random" feat if you ask me.
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The "in between" stages aren't useless. The whole concept of "in between" stages doesn't even make any sense. If at any point, an organism wouldn't be able to survive, it would go extinct.
I RTFA, big mistake. Nobody knows, and all arguments are counterdictory to each other. In other words, an article about we don't know why, and we are saying we don't know why. I find myself not breathless waiting for the next article from Captain Obvious.
Interesting reports like this can be rare as hens teeth.
There are plenty of birds that prey on mammals, and while none of them eat people for the most part, plenty of other critters do.
The example I use is Butterflies, which change from a crawling creature to one that flies, mid life. Incredible "random" feat if you ask me.
It's not random. The ability for adult insects to fly evolved gradually. That has nothing to do with the fact that insects go through metamorphosis, which most likely evolved independently and prior to the capability of flight
Your argument makes as much sense as saying: "I don't believe evolution because people can talk using air even though they spend 9 months sealed up in a bag of water."
Every member of a species is an in-between stage. You carry with you mutations in your genes. Yes, useless. Doesn't prevent you from procreating. If you do, your genes will end up in another individual who happens to get another mutation. Perhaps that does something; perhaps it does and it tweaks a protein's specificity. Mutations that don't have an effect now may have one in the future when more mutations build up. Mutations are not directed, occur without purpose (selection is directed: you get offspring or not).
Glucose oxidase (GO) oxidises glucose. That's what it does, in every organism that has it. Glucose oxidase (GO) of a human and a chimp are very similar. Those of a rose and a dandelion to each other too. As their purpose is just to oxidise glucose, it would have been the death of the theory of evolution if a human's GO and one of the plant GO were more similar than that of the chimp's. But that's not the way it is. It is just one of the powerful tests that the theory of evolution passed, and even better provides an explanation for.
There certainly is a lack of knowledge how everything evolved; but that's not a problem. The only problem the theory of evolution suffers from is people's lack of understanding, or willingness to take the effort to understand.
Butterflies? They didn't evolve in one generation. The earth is very very old. Insects are the most popular animals. Lots and lots and lots of mutations resulted in a plethora of different species. Amazing, yes. God of any particular flavour required? No.
Bert
Apparently they were more successful than the ones with just teeth. That's all it takes.
He is being deliberately contra-dictionary.
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Exactly my point. Half Beak, Half Teeth doesn't make sense.
Umm, the universe is not limited to doing only those things that make sense to YOU. I'd even say it's pretty damn arrogant of you to presume your powers of comprehension are literally some kind of universal limiting factor.
"I can't figure out how evolution could have worked, ergo it must be impossible."
Sure. The powers of your brain cells place limits on biological processes that happened hundreds of millions if not billions of years ago? Uh huh. I bet your unicorns fart butterflies, too.
Hell, just for shits and grins let's assume that God did in fact create humanity in His image. He's God - omniscient and omnipotent. If He wanted to create man in His image by using evolution, He could do just that.
Modern biologists tend to shy away from the idea of reptiles entirely. It's a bit of an ugly classification.
I RTFA, big mistake. Nobody knows, and all arguments are counterdictory to each other. In other words, an article about we don't know why, and we are saying we don't know why. I find myself not breathless waiting for the next article from Captain Obvious.
Good science involves being very clear about what you don't know.
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I think it has more to do with being light weight since birds fly. After all, not all birds dig for grubs. Of course, not all birds fly anymore, but maybe the common ancestors did.
Another thing, birds evolved from reptiles. I watched the science documentary series 'Your Inner ...' (Inner Fish, Inner Reptile, etc). They mentioned that reptiles can replace their teeth but the teeth are undifferentiated, whereas mammals, who only get two sets, have them custom designed with a tight fit so some are good for tearing flesh, some for grinding, etc. Presumably the teeth the birds lost would have been less efficient reptile teeth.
In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
Apparently they were more successful than the ones with just teeth. That's all it takes.
It doesn't even necessarily take that much. Sometimes the mutated offspring only has to be not so much worse that it can't manage to reproduce. It could potentially be slightly worse, as long as there's enough room for both to survive.
I don't think that a TV series would have kept it. Nearly all science fiction shows have lampshaded it with some sort of technology. Doctor Who explains that the TARDIS does it. Farscape did it with injectable nano devices of some kind. Star Trek does it with the Universal Translator. Babylon 5 explains that since the station's primary function is commerce and since commerce for humans is generally conducted in English, that's why nearly everyone who speaks with humans speaks in English, and if everyone speaks English as a second language because they came to the station for commerce purposes, they'd probably speak English with each other as well.
Language would get in the way of storytelling if this wasn't handled this way, unless a major part of the plot was to try to figure out how to communicate. Stargate the feature film had this, but the TV show could not have sustained itself on that.
Do not look into laser with remaining eye.
The problem I see with many people is that they see evolution as binary. Everything must be an advantage to be passed on and that mutations are bad. No, mutations are normal with some providing advantages and some are disadvantages. And as you pointed out, some traits have no effect whatsoever. Other traits appear to be a disadvantage or an advantage given the right environment. Fair skin, for example, is advantage in places like Norway where more vitamin D is produced with less light. It is a terrible disadvantage in places of high sunlight like the Sahara, American Southwest, etc.
And some traits are both an advantage and disadvantage like sickle cell anemia. It cuts the lifespan by years and is painful to deal with. However genetically it provides those with the genes an advantage when it comes to malaria which can cause death.
Well, there's spam egg sausage and spam, that's not got much spam in it.
They don't even have to be more successful all the time. Those could have been the underdog not so well suited to the environment, but there was a famine or flood or other event. The niches open up for whatever can move in like squatters. Either the local competiton dies off and the previous underdog is left alone there, or the underdog migrates to a less desirable environment that the competition doesn't like.
You see similar things today. We tend to think of very select niches for some species, such as a bird who only eats one type of insect. But we find species willing to adapt to sudden changes in the environment, not necessarily whole sale but a subset of them figure out that they can survive on a different type of insect even if it's not as yummy as the previous kind.