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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.
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.
SJW n. One who posts facts.
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.
excitingthingstodo.blogspot.com
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.
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.
Interesting reports like this can be rare as hens teeth.
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."
He is being deliberately contra-dictionary.
http://www.acetonestudio.com
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.
I should use this sig to advertise my book ISBN-13 : 978-1501515132.
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.