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Author Topic:   Is evolution of mammals finished?
RAZD
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Posts: 20154
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 4.1


Message 91 of 213 (386902)
02-24-2007 4:03 PM
Reply to: Message 90 by MartinV
02-24-2007 3:22 PM


Re: arbitrary classifications and niche knocks
Of course they exist. Even animals recognise them in order to mate themselves, to recognise what to hunt and what to avoid. It's a weird opinion that cats learn to avoid german shepard, bulterier, canis lupus etc and ...

They recognize species {in-group) and {out-group}. That's all that is required to exist, survive and breed. They would also learn to be wary of lynx and bobcat and mink.

Cats (and other animals) learn by experience. Unfamiliar type animals are treated with wary skepticism regardless of taxon group they come from. Parents (when around) pass experience to offspring. Learning works both ways: cats raised with dogs are not wary of dogs. That cats can peacefully coexist with dogs disproves your assertion.

They also certainly do not recognize {mammal} as a group - or any other taxon division - because it is an arbitrary group based on one of many common ancestors.

There is no classification beyond species that is NOT arbitrary on where the lines are drawn for {part of group} vs {not part of group}.

Message 89
It depends what exactly you remove. If you remove 75% animals from each species I would say nothing happens - remaining individuals will geometrically fill niches.

Seeing as the fossil evidence is that it was 75% of the species this does not address the real issue but is a non sequitur.

It also neglects the issue of those remaining 25% being isolated in two or more pockets of their former range, now in reproductive isolation. This would allow each sub-population to evolve differently as there would no longer be gene flow between the groups. Thus 75% reduction of each species could lead to massive opportunity for change that would not exist before.

Message 89
That's the question. Why crocodiles and sharks didn't occupy emptied niches?

Opportunity. Crocs and sharks did diversify as well, they just didn't compete sufficiently with whale ancestors to prevent their diversification. There was sufficient opportunity for whale ancestors to survive, breed and diversify.

Why after Ambulocetus left estuaries no other mammals entered it again?

Because they did not leave it all at once but in stages. As each stage was taken there was only PART of the "niche" to fill and the opportunities of all the competing species to take bits and pieces along the way means that no complete "niche" was left.

There are also lots of mammals that live in estuary environments, so this "niche" is not left empty nor vacant nor bereft of mammals.

You keep thinking that the niche defines the species. It's the other way around. As the species changes the niche changes with it because it is defined by the species.

Enjoy.

Edited by RAZD, : subtitle


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Chiroptera
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Posts: 6802
From: Oklahoma
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Member Rating: 6.8


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

This message is a reply to:
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Quetzal
Member (Idle past 4155 days)
Posts: 3228
Joined: 01-09-2002


Message 93 of 213 (386916)
02-24-2007 7:00 PM
Reply to: Message 92 by Chiroptera
02-24-2007 4:59 PM


Re: Weird.
But if you think it's partly insoluble, maybe I'm wrong.

Heh. You answered your own question. The only insoluble part is, as you said,

Chiro writes:

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.

THAT's the bit we can't really answer. Why this one and not that one? It's even worse when you're talking about time frames 30 mya. The only thing we can say is: that lineage DID, and that one DIDN'T.


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MartinV 
Suspended Member (Idle past 4112 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 94 of 213 (387656)
03-01-2007 6:40 PM


Mobbing
One of the interesting issue you somehow avoid to address too is the evolution of bats. In this case the problem of "emptied niches" is similar to that of evolution of whales. Competitors for emptied niches should be bats and birds.

There is observed phenomenon of mobbing bats by songbirds. Songbirds are often mobbing owls too. Such behaviour is hardly explainable by darwinism, because what competition we see there? I would say songbirds and other "day" birds should mobbing each other and not "night" birds/bats with which they do not compete at all (while they sleep when they hunt and vice-versa).

Surely mobbing between day/night flying animals has more to do with some more profound reasons as obligatory darwinistic struggle for survival. Animosity between day/night birds and bats show us some deeper recognition and "psychology" in animal realm.

We should take also into consideration the fact that maybe the mobbing is not the force that hindern bats to hunt during day.
Bats would have more what to feed during afternoon, when insects abundance seems to culminate.

quote:

Other studies indicate that an inadequate nocturnal food supply may negatively affect bat reproduction. The question arises therefore why do temperate insectivorous bats not fly in daylight more frequently? Four hypotheses have been advanced to explain the infrequency of daylight flying. These are overheating, competition, predation and mobbing by non-competitor species...

http://links.jstor.org/sici?sici=0269-8463%281991%295%3A4%3C518%3AWDIBIB%3E2.0.CO%3B2-P&size=LARGE

You see these four hypothesis are darwinistic ones. The problem is more complicated and probably we should have to try to find other explanation for nocturnal predation of bats as well as for mobbing.


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Chiroptera
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Posts: 6802
From: Oklahoma
Joined: 09-28-2003
Member Rating: 6.8


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

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MartinV 
Suspended Member (Idle past 4112 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 96 of 213 (387699)
03-02-2007 1:30 AM
Reply to: Message 95 by Chiroptera
03-01-2007 7:44 PM


Re: Mobbing
Do you see any darwinistic explanation for the phenomenon of mobbing between diurnal birds and nocturnal birds (bats)?

Take into consideration my previous post as well as observed fact that nocturnal birds aren't thread to diurnal birds at all.

quote:

This hypothesis is particularly plausible for cases in
which the immediate threat is questionable, such as
diurnal songbirds mobbing a strictly nocturnal owl
(Harvey & Greenwood 1978). Nevertheless, predators
do sometimes catch mobbers...

http://desrolab.sbf.ulaval.ca/documents/Desrochers_B%C3%A9lisle_Bourque_2002.pdf

-----------

I have already presented my opinion. There is some innate hate
of diurnal birds towards nocturnal ones as well as bats. This hate has nothing to do with darwinistic competion as well as with struggle for survival. Diurnal birds see these nocturnal creatures (including bats) something like "bastards".

If you see this explanation funny give me your neodarwinistic one. I would like to read some fun too.

Edited by MartinV, : No reason given.

Edited by MartinV, : No reason given.


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Wounded King
Member (Idle past 2378 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 97 of 213 (387706)
03-02-2007 2:46 AM
Reply to: Message 96 by MartinV
03-02-2007 1:30 AM


Re: Mobbing
Diurnal birds see these nocturnal creatures (including bats) something like "bastards".

I think you are in the ballpark, although maybe not with the bats, but rather than a split between diurnal and nocturnal it is between predator and prey species. Bear in mind that not all owls are strictly nocturnal so a prey species may well react to a nocturnal species which resembles a diurnal one. It may even be that they are reacting to characteristics of birds of prey in general, although this may be less likely since owls are quite distinct from the other raptors.

If you see this explanation funny give me your neodarwinistic one.

Without a lot more in depth behavioural study, ideally a generational one allowing something along the lines of a qtl analysis, there is no way to give anything close to a 'neodarwinistic explanation', only best guesses just a little better than just so stories. This isn't like mimicry where there is a whole lot of genetics available for us to explore, this is a complex behaviour requiring a sizable population of birds which about which we know little in the way of behavioural genetics and small potential in terms of manipulability of those genetics.

TTFN,

WK

Edited by Wounded King, : No reason given.


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PaulK
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Posts: 15439
Joined: 01-10-2003
Member Rating: 2.9


Message 98 of 213 (387707)
03-02-2007 3:06 AM
Reply to: Message 96 by MartinV
03-02-2007 1:30 AM


Re: Mobbing
According to this paper (only the first page and the abstract are freely available)


....mobbing by non-competitors was very rare (4/420 reports) and its consequences trivial.

So it seems that in Britain, bats are rarely mobbed by non-competing birds.


...Flying with aerial insectivorous birds was more frequent (19/420 reports) but antagonism was again uncommon

Even birds that directly compete with bats do not often attack them.

So I find the idea that there is any inherent drive in birds to attack bats implausible. It seems that in fact they do so only rarely, even when directly competing for the same food.


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RAZD
Member
Posts: 20154
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 4.1


Message 99 of 213 (387716)
03-02-2007 7:31 AM
Reply to: Message 97 by Wounded King
03-02-2007 2:46 AM


Re: Mobbing
You see kingbirds attacking crows and crows attacking raptors. Sometimes just one, sometimes two or three at a time.

You don't see all birds engaged in this kind of behavior, rather a few species do, and only in certain instances.

You also see bluejays rasing a ruckus around a raptor, but NOT attacking it.

Without a lot more in depth behavioural study, ideally a generational one allowing something along the lines of a qtl analysis,

Exactly. And painting all bird species for the behavior of some - as MartinV has done - is also unrealistic and misrepresenetative of the nature of things.

Enjoy.


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Quetzal
Member (Idle past 4155 days)
Posts: 3228
Joined: 01-09-2002


Message 100 of 213 (387731)
03-02-2007 9:23 AM
Reply to: Message 89 by MartinV
02-24-2007 2:55 PM


Re: Weird.
Sorry I didn't see this response earlier.

It depends what exactly you remove. If you remove 75% animals from each species I would say nothing happens - remaining individuals will geometrically fill niches. According previous information 85% of marine Orders survived K/T. So diversification of life remain partly unaffected after K/T in the Ocean.

However, that's not what occurred. The K/T extinction didn't remove 75% of the individuals from each species, it removed 75%-85% of all existing species. Also, as you move up the taxonomic scale (from species to order, for instance), the percentage gets smaller. For instance, only ~40% of all existing genera went extinct, although even here it was quite selective: 100% of the orders Ornithiscia, Sauriscia, and Pterosauria died, 75% of order Marsupialia, but only ~11% of Crocodilia, etc.

As to marine extinctions - approximately 60%-70% of all marine species went extinct. Again, selectivity is the rule: 100% of Rudists, 100% of aminoids, ~95% of the Coccolithophorids, 100% of mososaurs, pleisiosaurs, and Inoceramids went extinct. Etc.

I have a meeting. I'll try and get to your other points later today.


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MartinV 
Suspended Member (Idle past 4112 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 101 of 213 (387769)
03-02-2007 3:47 PM
Reply to: Message 98 by PaulK
03-02-2007 3:06 AM


Re: Mobbing
quote:

So I find the idea that there is any inherent drive in birds to attack bats implausible.

If it is implausible than I see no reason why bats do not flight during day. I mean darwinistic reason. I underestand the fact that bats are nocturnal due to "internal forces" that are independent from "emtied niches" "struggle for survival" etc...

There are much more insects available afternoon during day that during night. If bats are not hunting by raptors as extraordinaly delicious food and if bats are not mobbing by other birds I see no darwinistic reason why should they restrict to nocturnal hunting only.

quote:

It seems that in fact they do so only rarely, even when directly competing for the same food.

If songbirds are mobbing owls I don't know from what birds "judgment" or "reason" or instict it should be. Songbirds must somehow assume that owls are their competitors in insect feeding. How they know it - do they observe owls hunting customs during night? And obviously it is not true while owls feed on mice, lizards etc, too... So they are not competitors at all.


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PaulK
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Posts: 15439
Joined: 01-10-2003
Member Rating: 2.9


Message 102 of 213 (387771)
03-02-2007 3:58 PM
Reply to: Message 101 by MartinV
03-02-2007 3:47 PM


Re: Mobbing
quote:

If it is implausible than I see no reason why bats do not flight during day.

How about avoiding predators ? Accordign to the same study three times as many bats were attacked by predators as were mobbed by non-competing songbirds. Surely that is a better reason. Perhaps there is less competition for their preferred food, too.

quote:

If bats are not hunting by raptors as extraordinaly delicious food


Who says that they aren't ?

quote:

If songbirds are mobbing owls I don't know from what birds "judgment" or "reason" or instict it should be.


Owls and bats are very different. Owls are likely mobbed for the same reason that other raptors are mobbed.

quote:

Songbirds must somehow assume that owls are their competitors in insect feeding.


That IS silly. While the little owl - which does fly during the day anyway - largely goes for insects most owls are mobbed because they are potetnial predators of songbirds, not competition.

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MartinV 
Suspended Member (Idle past 4112 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 103 of 213 (387773)
03-02-2007 4:08 PM
Reply to: Message 101 by MartinV
03-02-2007 3:47 PM


Re: Mobbing
quote:

However, that's not what occurred. The K/T extinction didn't remove 75% of the individuals from each species, it removed 75%-85% of all existing species.

Nice you answered me at last. I supposed you had communicated only with Chiroptera on my issue.

I quote the fact that 85% of marine Orders survived K/T extinction. I am not any expert, but I give you an example. If nowadays meteorite kills 95% of mammalian species and yet 85% of mammalian Orders survive I will say nothing happened. It means this - there will be still some living bat species, some living whale species, some living rodent species, some living carnivora species, some living primates etc... There will be very great diversity of animals (even if 95% of species died and each Order preserved only 2 species instead of 180) that should occupy emptied niches. Because there are still left some aquatic mammals, some flying mammals, some predators, some ungulates etc... They do not have to evolve again. All basic "body plans" that are characteristic for Order survived.


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Omnivorous
Member (Idle past 1251 days)
Posts: 3808
From: Adirondackia
Joined: 07-21-2005


Message 104 of 213 (387775)
03-02-2007 4:27 PM
Reply to: Message 99 by RAZD
03-02-2007 7:31 AM


Re: Mobbing
Bird mobbing behaviors are among my favorites.

I, too, have noted the species specific behaviors you describe, perhaps most interesting the roll that jays play in alerting crows (both corvids, by the way, and clever as the dickens) and other species to the presence of raptors. It seems to be a case of "Hey, let's you and him fight!"

Our local jays sometimes mimic raptor calls in order to temporarily clear the feeders of competing species :): lying a blue streak, I suppose. Chimps have also been observed in this sort of deceptive distress vocalization in order to abscond with food.

It has always seemed to me that the crucial metrics were size, flight prowess, and numbers: the mobbing bird must be large enough to threaten the predator but sufficiently more maneuverable to avoid retaliation. The third ingredient seems to be numbers: you can attract gnatcatchers, warblers, and other songbirds during spring breeding season by imitating the call of the Eastern Screech-Owl, though the same call gets a lukewarm response other times of the year.

Small and not as omnivorously beak-equipped as the crows and kingbirds, these songbirds seem to mob only when they are numerous and when the reproductive stakes are high. Only a few of them are unlikely to inflict appreciable damage on any larger bird, while crows can deliver a nasty wound to a larger raptor, as can kingbirds to crows: even a single crow will play Red Baron to a raptor.

I once saw a murder of crows scramble to chase off a Cooper's Hawk, only to be in turn mobbed by kingbirds when they returned to the treeline. Cooper's Hawks prey on smaller birds, while all corvids are notorious nest predators.

Sorry I have no data to offer...just many long days of watching.


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MartinV 
Suspended Member (Idle past 4112 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 105 of 213 (387776)
03-02-2007 4:38 PM
Reply to: Message 102 by PaulK
03-02-2007 3:58 PM


Re: Mobbing
quote:

How about avoiding predators ? Accordign to the same study three times as many bats were attacked by predators as were mobbed by non-competing songbirds. Surely that is a better reason. Perhaps there is less competition for their preferred food, too.

So we should suppose that predators prefer somehow bats instead of other diurnal birds. Otherwise diurnal birds would became nocturnal animals too. Using darwinistic logic.

My point is this - humans do not like bats. It's old medieval tradition that bats were nailed on entry-doors down heads (only bats, no birds). This hatred has some psychological reason. If we omit psychological reasons in nature we might lost plausible explanations as well. It's like to explain force between magnets by allmighty gravity (=nocturnal mode of life is caused by allmighty struggle for survival).


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