Evolution, maybe someone can explain?

[Pogo]

According to the theory, they are not unrealistic scenarios. https://www.esconi.org/esconi_earth...are-you-an-ape-or-a-fish-both-or-neither.html

No, that has nothing to do with what can potentially happen, those categories are as a result of our history.
that tiny bit of a link from 2012 is about cladistics.

 

[TagliatelliMonster]

(I meant gills not lungs in my original question) my mistake

So given enough time luck and selective pressure......what would prevent humans to evolve in to swiming crestures with gills and sacales? Something that you would call a fish




Yes according to how we clasify animals today, whales are mammals not fish.... then what? What is your point?

Lammal

Fish are on another branch of the evolutionary tree of life.
In evolution, species don't jump branches.

Descendants of humans, will be sub-species of humans. Mammals.

Look at whales for an example of how it might look like for a mammal to evolve into a "fish-like" creature.

 

[TagliatelliMonster]

Why is it impossible? If fish could Evolve to humans, why could humans not evolve to -- something like water-dwelling animals?

"fish" and "water-dwelling" animals are quite different.
Whales are "water-dwelling" animals. They aren't fish.

Is this all this really is? Just a word game?

Please do explain WHY you maintain that humans could not evolve to water-dwellers.

I didn't say that. I said they wouldn't turn into fish.

 

[TagliatelliMonster]

maybe you might consider that the theory IS wrong.

It isn't.

It can't be "Disproven,"

The very post you are replying to, shows at least one way in which it could be disproven.
There are many many many more ways.

Every genome sequenced has the potential to disprove it.

because nothing in science can be proven, isn't that the case?

"proven" is not the same as "disproven".

Theory can't be proven, correct.
They can only be supported. They an also be disproven.

In fact, one could say that science isn't in the business of proving things, but rather in the business of disproving things.
When you design an experiment / test for a hypothesis / theory... Then a good experiment or test isn't one that is designed to confirm the idea, but rather one that is designed to attempt to disprove it.

When you consistently go out of your way to try and disprove an idea and then fail at every attempt, then that is strong evidence in support of the idea. Much stronger then going out of your way to merely find evidence to confirm it.

Therefore, it can't be "DISproven."

False. Learn the difference between "proving" and "disproving".

So according to the theory, humans could "evolve" to be water-dwellers.

Water-dwellers, yes. Fish, no.

 

[TagliatelliMonster]

That has nothing to do with the theory of evolution, which is done, according to the theory, by mutations and survival by whatever makes it according to the circumstances.

It's a perfect analogy. The reason you don't realize it, is because you insist on being ignorant on how evolution works.
I understood it perfectly.

 

[TagliatelliMonster]

In the meantime I'm sure you are honest enough to figure chimps could evolve given what some call circumstances, to water dwellers. Sure, according the theory it would take a long time but given the theory it could happen. Why not?

Talking about being honest, perhaps you should acknoweldge how the goalpost is changing here from "fish" to "water-dwellers".

Want examples of land walking mammals that evolved into water dwellers?
Whales.

Are they fish? No.

 

[TagliatelliMonster]

Yes because fish*is* a coloquial term ....like bug or worm.


There is no scientific definition of fish

Which is a good reason for why this discussion here is problematic. A coloquial term is being used in context of cladistics to make a silly point about evolution. For this reason, any answer given is going to be ambiguous and one could argue about it till we are blue in the face.
Since you KNOW this is not a cladistic term, and yet still ask / press the question, makes me question your intellectual honest / sincerity.

Because then you know that WHATEVER the answer is going to be, you'll always be able to argue about it.

So let's leave the colloquial term behind then and let's start using proper terminology.

Look at this phylogenetic graph:

Here's a clade that includes all "fish".
Note the one that is highlighted in yellow. That group includes lobe-finned fish as well as tetrapods
So technically, if you want to be a D about it, all tetrapods actually already *are* fish and none would have to evolve into a water-dweller to "return" to being a fish.

The point: all descendents of species sitting on that yellow branch, will always remain on that branch. Regardless if they evolve into water-dwellers, air gliders, flyers, underground blind creatures, whatever. Mammals will produce mammals. Regardless if they live on land like humans or in the water like whales.


EDIT: typo

 

[TagliatelliMonster]

What is a fish?

evolution.berkeley.edu

Here is a phylogenetic tree of what we think of as fish, well except for some of the sarcopterygii (the yellow line). They all share a common ancestor and so a cladogram would be possible though not well defined from the top right. We also know that Gadiformes (cods) no matter how much their desendants don't look like their ancestors, there will be a pathway back to what we would identify as a cod. So what is a fish.

A clade is a group of organisms on a phylogenetic tree that includes a single ancestor and all of its descendants:

To identify a clade on a phylogenetic tree, you can imagine cutting a single branch off the tree. All of the organisms on that branch make up a clade.

Clades are also known as monophyletic groups, which comes from the Greek word for "single clan". Here are some characteristics of clades:

Nested
Clades are not mutually exclusive, but are nested within one another. For example, a taxon can belong to multiple clades.

• • Shared features
    Organisms in a clade share similar features that they don't share with other organisms in the tree.
  • Common ancestry
    All members of a clade share a portion of history, the internal branch that connects the clade to the rest of the tree.
    

We could define fish a everything to the right of Sarcopterygii and it would be a clade of what any five year old would call a fish. since they all share a common ancestor that is a group you can't move in to because no matter what you do you can't change your ancestry. Five year olds would probably not include hagfish and lampreys as fish, however they are fish from a biological standpoint so we could make a fish clade by moving to the bottom of the tree and calling that the definition of the fish clade. Again, there is no process to change ancestry so nothing can be added to the fish clade.
But now we have the problem of things most five year olds would consider a fish if ever they saw one which is the coelacanth. It is a sarcopterygian, that segment we wanted to leave out because it includes us and we aren't fish.
So how do we define fish, Is it the clade that includes all the things we think of as fish or just the portion of the tree to the right of Sarcopterygii without coelacanths and lampreys or all of them. If that definition we cannot ever be fish as we don't share an ancestry. Or we include the left portion and we are fish.

Any other setup is excluded by our understanding of evolution and requires you as the proposer to do a lot of work to rewrite several hundred years of science.
Personally, I don't think you are up to it. The best you could do is add fish-like for something that isn't a fish except it satisfies your inner five year old.

Ha! I just posted this exact graph as I was reading the thread. I click "post reply", read the thread further down and see you already posted it...

 

[TagliatelliMonster]

Strawman......I never said that mammals are fish

As explained..... if you want to be technical and insist on mixing colloquial terms with proper biology jargon, then in fact yes: mammals ARE fish.
Look at the graph posted.

If we are going to consider "fish" as a cladistic group, then all tetrapods are fish.
But in the colloquial sense of the word, what we actually mean by the word "fish" is everything on that graph except the descendents of sarcopterygii. Meaning: all the other branches.

I said that mammals could evolve in to something that we would call fish (given enough time luck and selective pressure)

No, they would not. Unless, off course, one goes down the incorrect and / or ignorant colloquial route again.
My 4-year old daughter would call a whale a "fish" also if she saw one.

The fact that you had to make a strawman out of my argument strongly suggests that you Grant the argument. (But won't admit it)

Says the guy who insists on sowing confusion by knowingly mixing colloquial terms with biological jargon.

 

[TagliatelliMonster]

....... and that population split started at the Tower of Babel - Genesis 11:1

No.

 

[leroy]

BTW, fish have not evolved independently 20 times, their are many species (I saw 29000 in one place) but they are all related and not independent.
Basic fail.

Again, there are many (around 20) independent clades that we call “fish” each one evolved independently from a “none fish”………………..fish is a generic term, not a biological term

 

[leroy]

Still not strawman. Just pointing out facts about cetaceans (whales, dolphins & porpoises).

Because gills are already not required for dolphins, porpoises & dolphins. Anytiime, they need air, they swim to the surface.

Crocodiles & turtles also spend more time in the water than on land, and they have about around tens of millions of years, without ever developing gills or needing them. And when the time come for them to lay their eggs, they don’t lay them underwater like with fishes and amphibians, instead they go to dry land, where they would bury their eggs, like most reptiles do.

It has nothing to with magical forces. It is just that selective pressures haven’t given them gills as neither cetaceans (whales, dolphins & porpoises), nor crocodiles & sea turtle, requiring gills or becoming anamniotic (lay eggs underwater).

Penguins spent time on land and on water, they move faster in water, and yet they also don’t require gills. When penguins lay their eggs, they don’t lay them underwater (like fishes & amphibians), instead they lay them on dry land or on ice, and then sit on the eggs, like birds do in nests.

Evolution go forward, not backwards.

if anyone is strawmanning, it is you, as you kept bringing up chimpanzees.

Why would chimpanzees need to become fish-like, when they lived in tropical rainforests or savannahs? There are no selective pressures for chimpanzees live underwater. So you asking questions that are ignorant.

Again strawman………………I am not saying that there *is* selective pressure for evolving gills in dolpphis…………….I am saying that if there where selective pressure (+luck+time) their ancestors could develop gills………………..

 

[Pogo]

Again strawman………………I am not saying that there *is* selective pressure for evolving gills in dolpphis…………….I am saying that if there where selective pressure (+luck+time) their ancestors could develop gills………………..

If wishes were horses then beggars would ride and other trivialities, BTW, a better example of air breathers becoming fully aquatic would be sea snakes who can stay submerged for 5-6 hours because they have evolved to absorb oxygen through their skin. Gill formation starts from a very different organism than one that has come to rely on lungs.

Go back and learn the basics of evolution and developmental theory.

 

[Pogo]

Again, there are many (around 20) independent clades that we call “fish” each one evolved independently from a “none fish”………………..fish is a generic term, not a biological term

learn what a clade is.

 

[leroy]

Which is a good reason for why this discussion here is problematic. A coloquial term is being used in context of cladistics to make a silly point about evolution. For this reason, any answer given is going to be ambiguous and one could argue about it till we are blue in the face.
Since you KNOW this is not a cladistic term, and yet still ask / press the question, makes me question your intellectual honest / sincerity.

Because then you know that WHATEVER the answer is going to be, you'll always be able to argue about it.

So let's leave the colloquial term behind then and let's start using proper terminology.

Look at this phylogenetic graph:

View attachment 99457

Here's a clade that includes all "fish".
Note the one that is highlighted in yellow. That group includes lobe-finned fish as well as tetrapods
So technically, if you want to be a D about it, all tetrapods actually already *are* fish and none would have to evolve into a water-dweller to "return" to being a fish.

The point: all descendents of species sitting on that yellow branch, will always remain on that branch. Regardless if they evolve into water-dwellers, air gliders, flyers, underground blind creatures, whatever. Mammals will produce mammals. Regardless if they live on land like humans or in the water like whales.


EDIT: typo

I agree with your post above, all I did was a small correction in your previous comments

You said

Yes, they do. And mammals remain mammals. Which is exactly why mammals won't evolve into fish. Because that would mean they aren't mammals anymore

My feedback to you was that in this case (since fish is a colloquial term and not a true clade) one could in principle be both a mammal and a fish…………there is nothing in cladistics that prevents that possibility.

So let's leave the colloquial term behind then and let's start using proper terminology.

ok just keep in mind that *you* where the one who used the colloqual term "fish" (hence my previous comment correcting you)


This was not intended to be a big of a deal, you made the tiny little mistake of using a colloquial term (fish) when you should have used the name of a true clade in order to make your point*……………your point is true BTW you simply used and incorrect word/example

For context : Your point (which I grant) was that one clade doesn’t evolve in to another clade……..(mammals by definition will never evolved in to birds nor in to any other clade outside the “mammal branch”)

 

[leroy]

If wishes were horses then beggars would ride and other trivialities, BTW, a better example of air breathers becoming fully aquatic would be sea snakes who can stay submerged for 5-6 hours because they have evolved to absorb oxygen through their skin. Gill formation starts from a very different organism than one that has come to rely on lungs.

Go back and learn the basics of evolution and developmental theory.

Go back and learn the basics of evolution and developmental theory.

Ok, would you quote my actual words claiming something that is wrong?.................. NO you can´t............So please stop implying that I don’t understand de basics of evolution

 

[Pogo]

Again strawman………………I am not saying that there *is* selective pressure for evolving gills in dolpphis…………….I am saying that if there where selective pressure (+luck+time) their ancestors could develop gills………………..

No, evolution does not have a purpose or a goal so there is no such thing as selective pressure to form gills.
Your hypotheticals only express a lack of understanding of evolutionary processes.
That said there would be some advantage to breathing under water, such as in the sea snakes who have some ability to breath through their skin.

 

[TagliatelliMonster]

Again, there are many (around 20) independent clades that we call “fish” each one evolved independently from a “none fish”………………..fish is a generic term, not a biological term

The bolded part, makes the "independently evolved from..." part completely meaningless for making a point about evolution.

 

[leroy]

As explained..... if you want to be technical and insist on mixing colloquial terms with proper biology jargon, then in fact yes: mammals ARE fish.
Look at the graph posted.

If we are going to consider "fish" as a cladistic group, then all tetrapods are fish.
But in the colloquial sense of the word, what we actually mean by the word "fish" is everything on that graph except the descendents of sarcopterygii. Meaning: all the other branches.




No, they would not. Unless, off course, one goes down the incorrect and / or ignorant colloquial route again.
My 4-year old daughter would call a whale a "fish" also if she saw one.





Says the guy who insists on sowing confusion by knowingly mixing colloquial terms with biological jargon.

I find it perplexing that you where the one who used a colloquial/generic term in a context where you should have used a technical term (a true clade) in order to make your point………………I took the time and corrected you in a very nice and respectful way………………………. But for some strage reason I end up taking your insults and condescending words.

Why didn’t you simply say “true Leroy, “fish” was not an appropriate term to use to establish my point thanks for the correction”

 

[Pogo]

Ok, would you quote my actual words claiming something that is wrong?.................. NO you can´t............So please stop implying that I don’t understand de basics of evolution

But it is true as you demonstrate with most every post such as this recent series asking if given enough time would air breathers develop gills.
It is a perfect example of not understanding at a very basic level.