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Author Topic:   Is evolution of mammals finished?
Chiroptera
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Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 3 of 213 (383625)
02-08-2007 5:27 PM
Reply to: Message 1 by MartinV
02-08-2007 4:50 PM


quote:
In Eocene times -- say between 50,000,000 and 30,000,000 years ago --small primitive mammals rather suddenly gave rise to over a dozen very different Orders -- hoofed animals, odd-toed and even-toed, elephants, carnivores, whales, rodents, bats and monkeys. And after this there were no more Orders of mammals ever evolved. There were great varieties of evolution in the Orders that had appeared, but strangely enough Nature seemed incapable of forming any more new Orders.

This is not quite true. The Eocene did not suddenly give rise to over a dozen new orders. The linked chart shows quite clearly that these orders began radiating at about the time of the KT-boundary, at the beginning of the Paleocene.

It seems pretty straightforward about what happened. A mass extinction emptied a lot of different ecological niches, which the surviving species filled during radiative adaption, perhaps allowing pretty innovated "designs". Once the niches began to be filled, natural selection then intensified, preserving the best adapted of the new designs in the newly opened niches, and by the beginning of the Eocene pretty standard designs (the different orders) had been established. After this point, large scale changes, drastic innovations would move the morphology off of the peak on the fitness graph, so natural selection would then be fairly conservative in preserving those forms that have proven to be highly adapted, and preventing poorly adapted innovations from taking hold in the now crowded ecosystems.

My guess is that after human race has run its course, the end result of the mass extinction which we have produced will be that the relatively few remaining species will again undergo radiative adaptation, and we would (if we were around to observe it) the rise of many more new orders.


This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
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 Message 1 by MartinV, posted 02-08-2007 4:50 PM MartinV has not yet responded

Chiroptera
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Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 9 of 213 (383792)
02-09-2007 8:31 AM
Reply to: Message 7 by Alan Fox
02-09-2007 8:01 AM


Re: Robert Broom
I can't find anything either, but I note that the year in your quote is 1910. Although scientists pretty quickly accepted common descent due to Darwin's efforts, there was a lot of controversy over what role, if any, natural selection played in the process. Darwin's theory is about natural selection -- the common descent part is fairly trivial. It is quite possible that Brown accepted a non-Darwinian theory of evolution.


This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
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Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 11 of 213 (383812)
02-09-2007 9:56 AM
Reply to: Message 10 by Alan Fox
02-09-2007 9:38 AM


Re: Robert Broom
quote:
As Robert Broom died in 1951, thus being unavailable for comment, I suggest the onus is on those who claim Broom was "anti-Darwinian" to find some reference in his writings that supports that assertion.

Davison does that in the essay linked in the OP. The quotes seem to show that Broom may have had some tendencies toward structuralist theories of evolution, but it's hard to say what relative importance Broom felt natural selection had in the process of evolution. At any rate, having supplied evidence that does seem to support the claim, the onus is now on others to read Broom's works to find out if these quotes are taken out of context and to find out what role, if any, he felt natural selection has.

-

quote:
Does not the fact that such evidence is not apparent, make it equally possible that Broom accepted mainstream Darwinian evolution?

Darwinian evolution was not the mainstream at that time; rather it was one of many possible theories that were discussed and studied. Common descent was almost universally accepted as a fact; there was still a lot of work to be done to determine the mechanisms of evolution.

It is very conceivable that Broom was not a Darwinian, there is no reason to assume that he was Darwinian, and if he wasn't then this would not count as a stain on his professional reputation.

Without actual evidence, it is hard to say what Broom believed. Davison supplied some evidence that Broom was not pure Darwinian, and now the onus is on those who would like to show that he was (if anyone really thinks this is an important issue). Maybe he was, maybe he wasn't, but I see no problem right now with the possibility that he wasn't.


This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
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Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 15 of 213 (383955)
02-09-2007 4:41 PM
Reply to: Message 13 by MartinV
02-09-2007 12:37 PM


Re: Robert Broom
Broom's evolutionary theory is based on the existence of some sort of 'intelligent spiritual agency' of two types: a) the lower agency, present in animals and plants, of limited vision and limited power, and b) that of a much higher type which has planned and directed evolution (via directing from time to time the former, inferior agencies).

Huh. So Broom was a Lamarckian. Interesting.

-

quote:
It would mean that in the sea there were more convinient niches as in the land for whales/sirenians predecessors.

What this meant was that among one population of Pakicetus, for example, which were living near a riparian or estuarian environment, those that were slightly better able to make use of the water (for protection or as a source of food) were better able to reproduce and leave behind offspring than those that were better suited for an entirely terrestrial existence. Of this slightly more aquatic version of Pakicetus, those that were ever so slightly more efficient at the use of the aquatic environment were more likely to leave offspring than the less aquatically adapted. After a while, you have an aquatic or semi-aquatic version of Pakicetus. Some environmental change causes the completely terrestrial Pakicetus to become extinct, leaving only the aquatic descendent species.

I'm not sure what "more convenient niche" even means.

-

quote:
Oddly enough indigenous sea animals did not filled these emptied niches by radiative adaptation but mammals from land overtook them.

There were probably many empty niches in the oceans -- I believe that the KT-extinction hit marine life harder than land life, but I'm not sure. At any rate, some niches were filled by land animals adapting to the seas, and other niches were filled by sea animals who likewise adapted to the newly opened environments from different niches. I bet that in examining the fossil record one would see an increase in new orders in all surviving classes at this time, including among fish, crabs, and whatever.

-

quote:
Yet after Eocene there was no other succesfull attempt to enter the sea and air. Why?

Maybe the niches were already filled. There was no more room for new entrants.

-

quote:
Due to strong selective pressure even Pinnipedia did not manage
entered the water completely and freezed in their half-state.

Sure. If like Broom

Broom's evolutionary theory is based on the existence of some sort of 'intelligent spiritual agency' of two types: ... b) that of a much higher type which has planned and directed evolution....

one has an a priori commitment to some vague Lamarckian force that compels species to evolve in particular directions, then I can see how this is difficult to understand.

But in the absense of anything forcing evolution, particular in the absense of anything forcing evolution in a particular direction, why should they evolve into a more aquatic species? Presumably they do quite well the way they are. Those better adapted to a more purely aquatic life would not fare as well as the present pinnipeds, those better adapted to a more terrestrial environment would not do any better either.

-

quote:
On the other hand your theory mean that natural selection seems to be an antievolutionary force that tend to preserve pre-existing species already fully developed. It eliminates, destroy all novelties.

Sure. It can be. In fact, pre-Darwin that is what naturalists believed that natural selection did. Before Darwin it was believed (at least by the functionalists) that each species was already perfectly adapted to its environment, and that therefore any variation off of the archetype would be less adapted and removed by natural selection. In fact, one of the biggest obstacles to Darwin's theory was that people had a difficult time imagining natural selection as positive, creative agent as opposed to the traditional view of it being a negative conservative one.

And it makes sense. Imagine the graph that measures "fitness" as a function of "morphology". If a species is already at a local maximum, then any change in morphology will make the individual "less fit", and natural selection will remove it -- hence natural selection will tend to prevent evolution.

But a change in the environment (like a mass extinction) will change what is considered "fit" -- it will take the species and plop it right on a new and different graph, not necessarily at a peak. Now there is a direction "up" and variations in morphology that are in this direction will be selected for; we will now see evolutionary change.


This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
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 Message 13 by MartinV, posted 02-09-2007 12:37 PM MartinV has responded

Replies to this message:
 Message 20 by MartinV, posted 02-11-2007 9:43 AM Chiroptera has responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 21 of 213 (384370)
02-11-2007 10:39 AM
Reply to: Message 20 by MartinV
02-11-2007 9:43 AM


Re: Robert Broom
quote:
Broom believed that evolution is directed by spiritual forces. I don't see connection with Lamarck's thesis that organism can pass on characteristics it acquired during its lifetime to its offspring.

Because you don't know what Lamarck's theory was.

Broom's evolutionary theory is based on the existence of some sort of 'intelligent spiritual agency' of two types: a) the lower agency, present in animals and plants, of limited vision and limited power, and b) that of a much higher type which has planned and directed evolution (via directing from time to time the former, inferior agencies).

This is a pretty good, but short, description of Lamarck's theory. Except that he felt that the two agencies could be explained through naturalistic means rather than "intelligent spiritual" ones. The acquisition of acquired characteristics was a common belief at the time, shared by Darwin as well, and was accepted as "folk wisdom" until modern genetics showed it to be wrong.

-

quote:
And might be there were no vacant niches in the oceans at all. Yet land mammals pushed back all species from their "local maximums" there.

So "there might be no vacant niches" becomes "land mammals did push back all species".

Anyway, as long as there might be vacant niches, then there would be no other species to be "pushed back" and natural selection has not been discredited as an explanation for the observed phenomenon.

-

quote:
Anyway I have never heard about adaptive radiation of water species during the period discussed.

So go read up on the evolution of post-KT marine life and report back to us on what you find.

-

quote:
Maybe they would.

Maybe. But as long as "maybe not" natural selection has not been discredited as the best explanation.

-

quote:
Maybe just evolutionary potentiality of Pinnipedia became exhausted.

Maybe. But as long as there is a "maybe not" natural selection has not been discredited as the best explanation.

-

quote:
And my guess is the opposite one.

Cool. So we can both write our own science fiction books without fear of plagiarizing each other.


This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
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 Message 20 by MartinV, posted 02-11-2007 9:43 AM MartinV has responded

Replies to this message:
 Message 26 by MartinV, posted 02-16-2007 2:49 PM Chiroptera has responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 39 of 213 (385860)
02-17-2007 5:09 PM
Reply to: Message 26 by MartinV
02-16-2007 2:49 PM


Re: Robert Broom
quote:
How it happened that mammals Pakicetus and Ambulocetus overcame sharks and crocodiles that survived K/T Yucatan meteorite impact very well? Subsequnetly fully adapted sharks and crocodiles were not so apt to occupy "emptied niches" of shallow warm waters of shores?

That's a good question. When people play pachinko, why does one person's ball fall more or less straight down, while another person playing the exact same machine see her ball bounce all the way over the side? Yet, despite not being able to answer even such a basic question, no one doubts that the motion of the ball is basically described by Newton's simple laws of motion. I don't know why you want do doubt Newton's laws just because I cannot describe exactly the path of a pachinko ball.

Evolution is governed by the environment. The environment contains lots and lots of factors that will influence the evolution of a species. Crocodiles that were too far from the "basic crocodile form" didn't survive to leave offspring. Why? Maybe the right mutations didn't occur that would have given them a survival advantage. Maybe the KT-extinction did not change the shape of the "fitness vs. morphology" function.

Why did Pakicetus evolve toward an aquatic environment? Well, evidently some Pakicetus had a mutation that allowed a more efficient use of a more aquatic environment, and these Pakicetus were able to thrive. Just like the pachinko ball, that is pretty much all we can say.

-

quote:
The whole thing was planned form beginning....

Huh? You mean the subsequent evolutionary history of life was already written in the first cell three and a half billion years ago? How does that work?


This world can take my money and time/ But it sure can't take my soul. -- Joe Ely
This message is a reply to:
 Message 26 by MartinV, posted 02-16-2007 2:49 PM MartinV has responded

Replies to this message:
 Message 44 by MartinV, posted 02-18-2007 8:02 AM Chiroptera has responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 47 of 213 (385956)
02-18-2007 1:37 PM
Reply to: Message 44 by MartinV
02-18-2007 8:02 AM


Weird.
quote:
Pachinko ball doesn't have predators hunting it like crocs and sharks. Try game again using pachinko ball made of meat in the pool overcrowded with crocks or sharks.

You seem to have an unhealthy obsession with crocodiles and sharks. Is this a national trait because Slovakia is landlocked? I suggest you try to make it to the Mediterranean on your next vacation. Even if you are too scared to go into the water yourself, go to the beach anyway just to watch the people. You will see lots of people playing in the water without being eaten by crocodiles and sharks.

Even today, we have lots of aquatic and semi-aquatic mammals -- whales, manatees, seals, nutrias, and otters -- all living in the water. Some of these avoid being eaten by crocodiles and sharks, and others manage to survive despite occassionally being eaten by crocodiles and sharks. So what is the problem with paleocene and eocene mammals living in or near water?

And what prevents some sort of direct evolutioned mammals from facing the same crocodile and shark problem? I don't think a crocodile will care much whether amulocetus evolved due to natural selection or through some sort of directed evolutionary process. A meal is a meal. Whatever prevents an directed evolutioned ambulocetus from being eaten by a shark will also prevent a naturally selected ambulocetus from being eaten by a shark.

-

quote:
According some popular medieval conceptions (Giordano Bruno was it's follower) matter possesed spirit once. Might be that spirit is going upwards and is now fully presented in humans. The spirit presented himself and his creativity in mammals during "adaptive radiation" during Eocene and before during "Cambrian evolution" in lowest phyla. That's why evolution of mammals is finished. Species do not possess as much spirit as once.

Heh.

Heh heh heh.

Hee hee hee hee hee hee hee hee hee.

BWAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!

-

Okay, so we're taking about some sort of New Age woo woo. That's fine, I just want to make sure we aren't talking about science any more.

-

But let's make sure I got this straight. You want to believe in some sort of directed evolution, so you have to come up with a "problem" for natural selection. The "problem" that you came up with is that the world is filled is demonic ravenous crocodiles and sharks that will gobble up anything that so much as touches water. But there is that magical spirit that not only forced mammals to evolve, but it also protected them from crocodiles and sharks. But this magical spirit has run out, so not only do mammals not evolve anymore, but they are now all being eaten by crocodiles and sharks and that is why they are endangered.

Uh-huh. Thanks for sharing.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
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 Message 44 by MartinV, posted 02-18-2007 8:02 AM MartinV has responded

Replies to this message:
 Message 53 by MartinV, posted 02-19-2007 2:19 AM Chiroptera has responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 49 of 213 (385963)
02-18-2007 2:18 PM
Reply to: Message 48 by RAZD
02-18-2007 2:06 PM


Re: Crocodiles and Dinosaurs?
quote:
Do you know of any thoughts on the line of crocodiles being another surviving branch of dinosaurs, even though they reverted to cold-blooded behavior, due to this heart issue?

Birds and crocodiles are the surviving branches of the archosaurs (which also may have included the pterosaurs.

During the Permian, the therapsids were the most dominant land form. Then the PT extinction event (the worst that is known) allowed the archosaurs to become dominant; the extinction event that marked the end of the Triassic allowed one particular branch of the archosaurs, the dinosaurs, the opportunity to become dominant, and the the KT extinction then allowed one particular branch of the therapsis, the placental mammals, to once again reclaim their ancestor's place as the dominant land form.

Added by edit:
As far as the warm-blooded croc thing, I found this abstarct:

We present other evidence for endothermy in stem archosaurs and suggest that some dinosaurs may have inherited the trait.

I also found an old Pharygula article that I remembered spoke of this.

Edited by Chiroptera, : No reason given.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
This message is a reply to:
 Message 48 by RAZD, posted 02-18-2007 2:06 PM RAZD has responded

Replies to this message:
 Message 50 by RAZD, posted 02-18-2007 3:33 PM Chiroptera has responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 51 of 213 (385969)
02-18-2007 3:38 PM
Reply to: Message 50 by RAZD
02-18-2007 3:33 PM


Re: Crocodiles and Dinosaurs?
quote:
So both are surviving dinos.

Oops. Not quite. Crocs are close cousins to dinosaurs, sharing a common ancestor that they do not share with any other living taxon.

But I am mostly responding because I found something cool on the Wikipedia article:

  • A few crocodilians were herbivores, e.g. Simosuchus.
  • The large crocodilian Stromatosuchus was a filter feeder.

Wow! How cool is that!


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
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 Message 50 by RAZD, posted 02-18-2007 3:33 PM RAZD has responded

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Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 59 of 213 (386095)
02-19-2007 3:26 PM
Reply to: Message 56 by AZPaul3
02-19-2007 11:28 AM


Re: Be careful of "niches."
quote:
Keep in mind that a “niche” is a human construct to describe the environment and life/reproductive style of an organism. There are no “empty” niches. There are no empty boxes in an environment sitting around waiting for some organism to evolve “into” them.

I was wondering when someone was going to bring this up. The fact is, a niche does not exist until there is a species that is actually occupying it. I realized that potential confusion that could arise using these terms carelessly, but I did so anyway. Sorry about that, folks.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
This message is a reply to:
 Message 56 by AZPaul3, posted 02-19-2007 11:28 AM AZPaul3 has not yet responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 60 of 213 (386097)
02-19-2007 3:38 PM
Reply to: Message 53 by MartinV
02-19-2007 2:19 AM


Re: Weird.
quote:
And perhaps you should try your next vacation somewhere at forgotten India's tidal estuaries or marine swamps.

Would three years in Africa on the equator count? There were crocodiles in some of the rivers. Sometime people got eaten. Sometimes they didn't. People, and animals, can use the rivers and only be eaten on occassion. Same with the oceans. Seals manage to survive as a species even though a few get eaten by sharks. The fact that completely non-aquatic deer can drink out of a river without being eaten to extinction, the fact that manatees can live in swamps without being eaten to extinction, and so forth shows that prey animals can coexist in the same environment as predators. In fact, if they couldn't the predators themselves would become extinct. So I see no reason why the transitional forms between, say, pakicetus and modern whales couldn't coexist with crocodiles and sharks; other animals manage to do it.

-

quote:
Might be crocodiles were gentlemen at that time and did not filled their own niches in order to enable enough time for hoofed Artiodactyla Pakicetus to became crocodile-like Ambulocetus in shallow water.

I'm not sure why you think that crocodiles should have grabbed up all the good niches (uh-oh, there's that word again) before ambulocetus had a chance to evolve into them.

-

quote:
Species aroused via saltationism - then they are adapted to the environment fully and can compete with those that have been already there.

Is there any, like, evidence that this can happen? You know, assuming we're going to pretend we are still talking about science?

-

quote:
And we don't need anymore darwinistic fairy-tales about emptied niches.

Heh. Except the Darwinist fairy-tale of "natural selection" has been verified to be a real phenomenon in the real world. Unlike your "magical spirit force", the motivations for which I am still trying to understand.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
This message is a reply to:
 Message 53 by MartinV, posted 02-19-2007 2:19 AM MartinV has responded

Replies to this message:
 Message 64 by MartinV, posted 02-20-2007 5:06 AM Chiroptera has responded

Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 69 of 213 (386250)
02-20-2007 2:46 PM
Reply to: Message 64 by MartinV
02-20-2007 5:06 AM


Re: Weird.
quote:
It was your explanation that mammalian radiation occured because of "emptied niches".

Was? It still is. The KT-event emptied a lot of niches. There was a lot of opportunity for dramitically new (at least new to the surviving species) ways of utilizing available resources, resources that suddenly became available to the surviving species (but were previously unavailable because they were being utilized by other species that were now extinct).

So, right after the Cretaceous, a series of mutations that would, over time, lead to a profound morphological difference could possibly result in a new viable species.

However, by the late eocene the new opportunities had either been already filled by new species adapting into them, or closed as the new species created new ecosystems where the potential niche could not be realized.

In this situation, natural selection would not, in general, result in profoundly new morphologies. First, because the new species had fully adapted to the newly established ecosystems so that small morphological differences from the average population norm would be less adapted to the lifestyle in which the species had adapted. Second, if the small changes made the individual better adapted to take advantage of a different set of resources, by this time those resources were already being utilized by a better adapted species. So in this case, natural selection would act as a relatively conservative force.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
This message is a reply to:
 Message 64 by MartinV, posted 02-20-2007 5:06 AM MartinV has responded

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 Message 70 by MartinV, posted 02-20-2007 4:08 PM Chiroptera has responded
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Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 71 of 213 (386283)
02-20-2007 5:40 PM
Reply to: Message 70 by MartinV
02-20-2007 4:08 PM


Re: Weird.
quote:
I would say that conception of "empty niche" that Pakicetus filled is more than questionable.

Yes, you keep saying that. Yet you haven't really explained why this is questionable.

You also haven't explained why you find the conception of a vaguely defined, unobservable "spirit force" to be reasonable.

Edited by Chiroptera, : clarity


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
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 Message 70 by MartinV, posted 02-20-2007 4:08 PM MartinV has responded

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Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 92 of 213 (386907)
02-24-2007 4:59 PM
Reply to: Message 85 by Quetzal
02-24-2007 12:15 PM


Re: Weird.
quote:
...it's really hard to follow his train of thought.

Heh. Ain't that the truth!

-

quote:
IOW, because there were aquatic predators which survived the event, they would have already been in an advantageous position to exploit the newly-available resources, so any "latecomers" like the proto-whales would necessarily be unable to move in.

Yes, I realize that this is one of the things that Martin has been saying. But I wasn't sure why Martin feels this way. This is why I was trying to get him to explain how his magically, spirit driven transitionals would have had any better chance at surviving than naturally selected transitionals. Unless Martin is an all-at-once saltationist -- as you say, it's not really clear what he is trying to say.

-

quote:
For instance, we see successful invasions of exotics all the time....

An even better point. Thanks.

-

quote:
Why didn't the existing surviving aquatic predators match the "explosive" radiation of the terrestrial mammals - to the point that nothing else could play in their sandbox?

It seems naive to me to assume that "all water species are basically the same" or that "all water niches are basically similar". I don't buy into the notion that somehow crocodiles and sharks were in any better position to take advantage new opportunities afforded by the KT extinction than terrestrial mammals were. But if you think it's partly insoluble, maybe I'm wrong.

-

quote:
Partly this is an insoluable problem - we simply don't know all the parameters of what makes one lineage more "adaptable" than another.

This may be close to what I was trying to get at in my pachinko example. Why does one ball travel more or less straight down, while another bounces all the way over to the side? If they were both subject to Newton's laws and gravity, then wouldn't we assume that they both would take the same paths? I guess there must be some sort of "spirit force" that guides the balls in a pachinko machine.

But in reality, we do recognize that Newton's laws are responsible. It's just that an exact calculation of the paths would require us to know a huge amount of data to great precision -- just hitting a peg just a little bit differently will create a whole different path.

In the same way, predicting how real species evolve (or do not evolve) in real ecosystems would require a great knowledge (with great precision) of all the factors in an environment, as well as exactly which mutations will arise. Furthermore, there may be developmental constraints as to what paths are even potentially possible.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
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Chiroptera
Member
Posts: 6563
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.9


Message 95 of 213 (387665)
03-01-2007 7:44 PM
Reply to: Message 94 by MartinV
03-01-2007 6:40 PM


Re: Mobbing
quote:
In this case the problem of "emptied niches" is similar to that of evolution of whales.

Indeed. Not much of a problem at all, actually.


Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
This message is a reply to:
 Message 94 by MartinV, posted 03-01-2007 6:40 PM MartinV has responded

Replies to this message:
 Message 96 by MartinV, posted 03-02-2007 1:30 AM Chiroptera has not yet responded

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