Although it is close to lizards and snakes, it is neither a lizard nor a snake. Only two species exist under the genus Sphenodon, and they have represented it proudly for 65 million years, that is, since the age of the dinosaurs
By: Adi Weiss
Although it used to live all over New Zealand, the sphenodon (Tuatara in the Maori language of New Zealand) now lives only on islands far from the coast of New Zealand, and is in danger of extinction. It is located in one of the most remote corners of reptilian evolution. Although it is close to lizards and snakes, it is neither a lizard nor a snake. Only two species exist under the genus Sphenodon, and they have represented it proudly for 65 million years, that is, since the age of the dinosaurs.
Like any reptile, the Sphenodon's skin is scaly. On his back are jagged bumps that gave him the meaning of his Maori name - "bumps on the back". The bumps are not rigid. They are soft and flexible and are used by him in courtship rituals. After mating, the female lays about a dozen eggs in a hole in the ground, where they usually stay for over a year (!) until they hatch. Its length can reach up to a meter at maturity. Among its many features, Sphenodon has a unique set of teeth, unlike other reptiles, and in the first months of its life it also has a third eye, its abilities are modest compared to normal eyes, and it is fixed above its head. It is speculated that this eye was designed to distinguish between light and shadow, or to absorb ultraviolet light rays. After a few months the scales grow over it and it closes. His metabolism is slow, similar to other reptiles, a fact that allows him a fairly long life. It is not yet known exactly how many years Sphenodons can live, and the guesses are around 150 years, putting it in line with other life spans, such as the distant ones of its turtle family.
Most reptiles need relatively high temperatures to warm their bodies, while the sphenodon actually prefers cold. The most comfortable temperatures for him are cº16-cº21, and his average body temperature will usually be below cº10. Only a few reptiles live in areas where the climate is cool rather than desert or tropical, and are not particularly active in cold weather.
The epithet "living fossil" doesn't exactly fit the reptile, because Sphenodon also holds an unusual world record: it is the animal with the fastest-evolving DNA. Since it split from its scaly relatives (the group to which snakes and lizards belong), its DNA sequence has undergone such rapid changes that in a very short evolutionary time it was able to develop adaptations that do not exist in its relatives. Such speed of change and adaptation was remarkable in the eyes of Jason Castriota, head of design at the Saab car company, and inspired by the Sphenodon invented The SCC Tuatara sports car, whose speed can reach up to 444 km/h!
Understanding the meaning of the rapid changes at the molecular level in the Sphenodon's DNA may not only shed light on the evolutionary development of the reptiles, but also answer questions related to medicine and the treatment of diseases. Various groups of researchers recognized the research potential of Sphenodon decades ago, and it is still being studied today.
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By the way, this is true only on the assumption that these are neutral mutations. If they are not - the story is completely different...
Miracles, in my estimation they will prolong the split precisely through fossils. Which can explain the contradiction between the molecular clock and the fossil findings.
Bio
If I understood you correctly, then your first conclusion is reasonable. A large proportion of the individual mutations have no effect, a smaller proportion are harmful, and an even smaller proportion confer a survival advantage. "Survival advantage" = an increase in the life expectancy of the reproduction rate relative to the rest of the population.
What is strange to me is your calculation. The way to arrive at 250 million years is by measuring the variation between the two genomes and using the rate of mutations to arrive at the time of the split. Apparently your assumptions do not match what those who set the 250 million years say.
Rival, you guess right, more or less.
Nissim, I am aware of the points you mentioned and that's why I mentioned that I have been here for Arj-Dor in Zevov for about a month. If we assume that one mutation per month is added to the genome, it takes a total of 8^10 months to completely change a genome of 8^10 bases. That is, after a number of millions of years, the entire genome will change between a fly and a mosquito. So after about 250 million years there will be such a large sequence similarity? The only conclusion is that most of the mutations in their coding genome are harmful and not neutral. Otherwise they would be cumulative. Another possibility is that 250 million years have not really passed.
A',
"Why should only one mutation happen every generation?"
Read my previous post... On the contrary, he claims that there were so many mutations at that time that the fly could not have remained a fly, it should have turned into at least a rabbit, or a doe 🙂
Why should only one mutation happen every generation?
There are millions of new mosquitoes in each generation, each of which has the potential to mutate. Of course, most of the mutations will not be useful. But those who do will be able to spread. Bio sees evolution as a sequence of father son father son. And this is not the case with sexual reproduction. In one generation there can be ten beneficial mutations that will spread or zero.
What's funny is that usually they complain that evolution didn't have enough time to change the animals, now he complains that the fly had so much time that it should have already turned into an elephant 😀 Go figure them out.
Bio
7^10 generations which is 8^10 years. A generation of flies is 10 years?
Then, you give a "discount" and divide the rate of mutations (which you suck from your finger) by 100? Divide???
And at the end you draw a conclusion that is not related to the matter, and after that you draw another conclusion that is not related to your first conclusion at all?
And all this - without any relation to the article...
bio,
Evolution does not claim that animals are constantly changing and developing, or at what rate this happens. If the animal reaches a state of balance with its living environment it may not change at all for hundreds of millions of years, as happened for example with sharks and crocodiles.
And I completely agree with A's answer.
Bio
I'm not a biologist. But if you ask your questions more in the form of a question and less of a statement of fact there is a good chance you will get an answer. I also had some questions about things I didn't understand about evolution and some very nice people here helped me understand. But no one will have the strength to answer seriously if you come in the section of proving.
The mosquito and the fly split something like 250 million years ago. Even with the large assumption that a mutation was added to the genome in each generation (instead of 100 at the standard level), it only takes about 7^10 generations, which is about 8^10 years, to change the entire fly genome (or most of it). And the fly and the mosquito are not 100% different in their genomes. Which means that most of the changes in the coded DNA are not neutral. Or alternatively - because the age of the world is too young.
Again and again an "expert" releases the believo
while another "expert" tries to answer with a "clever"
And the result - nonsense...
A.
I thought why is it for what, and why is it because of what.... I looked here –
https://www.safa-ivrit.org/synonyms/lama.php
And I'm probably wrong. Why is used for both reason and purpose, while why is only for reason.
Further testing.
Wikipedia says two different things in two places.
Moral: Don't trust Wikipedia?
I need a deeper examination if it is correct to say why and why
Miracles
I specifically checked on Wikipedia and you are wrong?
"Why" is the question of what the reason is, that is why it happened.
"Why" is the question why the goal.
In evolution, of course, you ask "what caused" what you don't ask is "why"
A.
You don't ask "why" in evolution, because there is no goal. Certain fish, very primitive, also have a fourth eye 🙂
This eye is connected to the pineal gland that produces melatonin, and melatonin affects the sleep cycle. In humans (at least) the melatonin production mechanism is affected by light through the eyes. So, maybe because of this, the third eye was not needed and it disappeared in most animals?
Third eye?!
If she doesn't help, why have her?
If she helps why block her?