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Author Topic:   How do "novel" features evolve?
RAZD
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Message 1 of 314 (655307)
03-08-2012 10:47 PM


what is novel?
idscience raised the old creationist question - how does macroevolution explain the development of novel features.

The big problem with this question is that macroevolution does not cause any evolutionary change.

All evolution occurs at the breeding population level by the process of microevolution - or just plain evolution:

(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities.

This is a feedback response system that is repeated in each generation:

What separates (micro) evolution from the macro view of evolution (macroevolution) is the process of speciation, as evolution occurs within the breeding population, and nested hierarchies are formed by speciation events, and macroevolution is just a macro view of what occurs over several generations via evolution and speciation.

If we look at the continued effects of evolution over many generations, the accumulation of changes from generation to generation may become sufficient for individuals to develop traits that are observably different from the ancestral parent population. This lineal change within species is sometimes called phyletic change in species. This is also sometimes called arbitrary speciation in that the place to draw the line between linearly evolved geneological populations is subjective and because the definition of species in general is tentative and sometimes arbitrary.

If phyletic change in species was all that occurred, then all life would be one species, readily sharing DNA via horizontal transfer (asexual) and interbreeding (sexual) and various combinations. This is not the case, however, because there is a second process that results in multiple species and increases the diversity of life.

(2) The process of divergent speciation involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other.

Over generations phyletic change occurs in these populations, the responses to different ecologies accumulate into differences between the hereditary traits available within each of the daughter populations, and when these differences have reached a critical level, such that interbreeding no longer occurs, then the formation of new species is deemed to have occurred. After this has occurred each daughter population microevolves independently of the other/s. These are often called speciation events because the development of species is not arbitrary in this process.

So is divergent speciation necessary to explain novel features?

Short answer: no.

Longer answer: it could occur during the process of the evolution of the feature, and it may even result in a speciation event, but it isn't necessary to explain the evolutionary process for developing a novel feature.

Thus we really only need look at phyletic change within species, or the basic process of evolution occurring over several generations.

How many generations?

But before we can begin to answer that, we first need to answer the question: what is a novel feature?

nov•el2 - (Collins English Dictionary - Complete & Unabridged 10th Edition 2009 © William Collins Sons & Co. Ltd.)adjective
of a kind not seen before; fresh; new; original: a novel suggestion

So a novel feature would be one that did not appear in the ancestral population.

We can look at dogs and ask couple of questions:

  1. would a dog with short legs and an elongated body compared to wolves show a novel feature?

  2. would a dog with webbed feet show a novel feature?

quote:
Newfoundland (dog)
The Newfoundland is a breed of large dog. ... Newfoundland dogs excel at water rescue/lifesaving due to their muscular build, thick double coat, webbed feet, and innate swimming abilities.[3]

The Newfoundland's extremely large bones give it mass, while its large musculature gives it the power it needs to take on rough ocean waves and powerful tides. These dogs have great lung capacity for swimming extremely long distances, and a thick, oily and waterproof double coat which protects them from the chill of icy waters. The droopy lips and jowls make the dog drool.[2]

In the water, the dog's massive webbed paws give it maximum propulsion. The swimming stroke is not an ordinary dog paddle. Unlike other dogs, the Newfoundland moves its limbs in a down-and-out motion, which can be seen as a modified breaststroke. This gives it more power with every stroke.[2]


bold added.

I could not find any examples of wolves with these characteristics, so are they novel features?

Creationists like to argue (pointlessly) that descendants of dogs will always be dogs (while evolution says the descendants will always be members of the dog clade), but what happens when these dog descendants develop novel features, like webbed feet?

We know that our dog breeds occurred by standard evolutionary processes, with artificial selection of traits that appear in the dog populations chosen by the breeders. The breeders do not cause mutations to occur, just select those they want in the breed from the ones that occur.

Is that enough?

Enjoy.

Edited by RAZD, : clrty

Edited by RAZD, : changed picture

Edited by RAZD, : title


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RAZD
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Posts: 20714
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Message 2 of 314 (655308)
03-08-2012 10:56 PM
Reply to: Message 1 by RAZD
03-08-2012 10:47 PM


biological evolution
this could also be added to Introduction to Evolution

Enjoy


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Message 3 of 314 (655310)
03-09-2012 9:50 AM


Thread Copied from Proposed New Topics Forum
Thread copied here from the How "novel" features evolve thread in the Proposed New Topics forum.

  
NoNukes
Inactive Member


Message 4 of 314 (655354)
03-09-2012 5:42 PM
Reply to: Message 2 by RAZD
03-08-2012 10:56 PM


Re: biological evolution
I'm glad to see this thread started.

I'm not competent to contribute much to it. But I'd like to see a PRATT addressed during the discussion.

A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution" . Dog breeding includes human intervention which can be viewed as being similar to an ID agent stepping in to add information allowing new features like wiener-dog legs.


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Tangle
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Message 5 of 314 (655363)
03-09-2012 6:52 PM


Similarly, the golden oldie of the peppered moth - they can switch between black/grey and white/grey but they can't switch to red or barber's pole stripes.

Life, don't talk to me about life - Marvin the Paranoid Android

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RAZD
Member (Idle past 296 days)
Posts: 20714
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Joined: 03-14-2004


Message 6 of 314 (655370)
03-09-2012 7:26 PM
Reply to: Message 5 by Tangle
03-09-2012 6:52 PM


Misunderstanding Peppered Moths Evidence
Hi Tangle

Similarly, the golden oldie of the peppered moth - they can switch between black/grey and white/grey but they can't switch to red or barber's pole stripes.

The natural selection that was observed in the peppered moth is addressed in Peppered Moths and Natural Selection. Expecting "red or barber's pole stripes" to occur on demand is a grave misunderstanding of how evolution works -- it is a reactive system not a purpose directed system. There has to be a cause for it to be beneficial to survival and breeding, and then there have to be mutations that can be selected.

Expecting the peppered moths to be about the evolution of new features is a misunderstanding of what the peppered moths are used for: evidence of natural selection.

Enjoy.

Edited by RAZD, : subtitle


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RAZD
Member (Idle past 296 days)
Posts: 20714
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Message 7 of 314 (655378)
03-09-2012 9:03 PM
Reply to: Message 4 by NoNukes
03-09-2012 5:42 PM


creating "information" is either easy or irrelevant
Hi NoNukes,

A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution" . Dog breeding includes human intervention which can be viewed as being similar to an ID agent stepping in to add information allowing new features like wiener-dog legs.

Curiously, the mutations that cause short legs are fairly common in many species, including humans - it's called Dwarfism.

The difference is between a random mutation occurring and it being spread into the breeding population is selection. Within the ecological challenges and opportunities imposed by artificial selection, there is a survival and reproductive benefit to having short legs for the dogs being bred that have them, and not having them would be detrimental. This is a rather demanding ecology to survive in, yes?

Now the problem with the creationist\IDologist claim about information is that they don't define what the concept means or even more importantly, how it can be measured. There is, however, some evidence that we can look at which shows that either the concept "nature cannot create the information" is either falsified or irrelevant

See Figure 1 from Nature 421, 264 - 267 (16 January 2003); doi:10.1038/nature01313

Walkingstick insects originally started out as winged insects (blue at start and top row). That diversified.

And some lost wings (red). And diversified.

And some regained wings (blue again). And diversified.

And one lost wings again (Lapaphus parakensis, red again).

And this doesn't even address the ones where one sex (usually male) has wings and the other sex doesn't (the red includes these, so it is hard to determine from this graphic how many times the female sex gained and lost wings independent of the winged males).

But the issue is -- if the loss of wings is information loss, then regaining wings is information gain ... or whatever was lost is not important to evolution.

Then there is http://www.millerandlevine.com/km/evol/DI/AcidTest.html

Where a gene that enabled the bacteria to metabolize lactose was intentionally deleted (information removed?) and the bacteria regained the ability to metabolize lactose (information regained? ... or doesn't constrain evolution).

There are other examples, and we could probably have a whole thread just on evidence that either information is gained, or the concept is irrelevant, to what can or cannot constrain evolution.

Enjoy

Edited by RAZD, : changed img to thumb for faster loading


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RAZD
Member (Idle past 296 days)
Posts: 20714
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Message 8 of 314 (655387)
03-09-2012 9:54 PM
Reply to: Message 7 by RAZD
03-09-2012 9:03 PM


Moving the topic forward
Hi NoNukes,

A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution" . Dog breeding includes human intervention which can be viewed as being similar to an ID agent stepping in to add information allowing new features like wiener-dog legs.

Curiously, the mutations that cause short legs are fairly common in many species, including humans - it's called Dwarfism.

The difference is between a random mutation occurring and it being spread into the breeding population is selection. Within the ecological challenges and opportunities imposed by artificial selection, there is a survival and reproductive benefit to having short legs for the dogs being bred that have them, and not having them would be detrimental. This is a rather demanding ecology to survive in, yes?

Now, if we take an ecology that selects for a carnivore with short legs ...

quote:

ingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Family: Mustelidae
Subfamily: Mustelinae
Genus: Mustela
Species: Mustela nivalis

We would not be surprised.

And if we then take a similar ecology and modify it to select for aquatic behavior with webbed feet ...

quote:

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Subfamily: Lutrinae
Genus: Enhydra
Species: E. lutris

We would not be surprised.

And here we have just two members of the same family evolving according to different ecological challenges and opportunities, with the same kind of evolution seen in dogs.

Enjoy.

Edited by RAZD, : changed img to thumb for faster loading


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Dr Jack
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(1)
Message 9 of 314 (655409)
03-10-2012 2:26 AM
Reply to: Message 8 by RAZD
03-09-2012 9:54 PM


Re: Moving the topic forward
With respect, the adaptive short legs of weasels and the dechondroplastic legs of those dogs are fundamentally different in genetics and morphology.

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Tangle
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(1)
Message 10 of 314 (655415)
03-10-2012 3:48 AM
Reply to: Message 6 by RAZD
03-09-2012 7:26 PM


Re: Misunderstanding Peppered Moths Evidence
RAZD writes:

Expecting the peppered moths to be about the evolution of new features is a misunderstanding of what the peppered moths are used for: evidence of natural selection.

The argument used by creationists against the peppered moth is the same as you're discussing in this thread - how 'novel' features evolve. They would say that the moth already has the genes to be light or dark so that they can be selected. So it's no big deal that they actually do get selected for when the trees change colour.

If the trees in the woods all suddenly got painted red and white, the moth would be wiped out because it can't develop a red and white gene to be selected for.

So in their eyes, God put the whole moth genome together and included a light and dark gene but omitted red. The moth can't produce red from nowhere.

Now of course many moths have red and white colouration in their palette and it's likely our peppered moth actually does too. But that doesn't help our cause here, because if the moth already has the gene then god put it there for the purpose of surviving a red pole event - the moth did not gain the gene as a result of the event.

Just saying........

Edited by Tangle, : No reason given.


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zi ko
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Message 11 of 314 (655418)
03-10-2012 5:29 AM
Reply to: Message 4 by NoNukes
03-09-2012 5:42 PM


Re: biological evolution
A creationist might state that nature cannot create the "information" required to produce novel features and "macroevolution"

There could be anotther responce version:
organism-environment interaction provides the needed information for mutations tobe somehow guided.

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Panda
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Message 12 of 314 (655421)
03-10-2012 6:12 AM
Reply to: Message 11 by zi ko
03-10-2012 5:29 AM


Re: biological evolution
zi ko writes:

There could be anotther responce version:
organism-environment interaction provides the needed information for mutations tobe somehow guided.


Yes. But the list of unevidenced fantasy causes is almost infinite in number.
So we try to ignore them - along with fairies, unicorns and flying spaghetti monsters.
When they become evidenced: then they are of interest.

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Message 13 of 314 (655427)
03-10-2012 8:31 AM
Reply to: Message 11 by zi ko
03-10-2012 5:29 AM


Re: biological evolution
Hi Zi Ko,

Unless you're including evidence to support your arguments, please do not post in this or any other science thread.

Also, in this case you're trying to introduce your own preferred hypothesis of environment-directed evolution. That is not the topic.


--Percy
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RAZD
Member (Idle past 296 days)
Posts: 20714
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Message 14 of 314 (655429)
03-10-2012 8:51 AM
Reply to: Message 9 by Dr Jack
03-10-2012 2:26 AM


adaptation to different ecological challenges and opportunities
Hi Mr Jack

With respect, the adaptive short legs of weasels and the dechondroplastic legs of those dogs are fundamentally different in genetics and morphology.

But the point is that the dechondroplastic legs could be selected for a specific ecology, such as occupied by the weasel.

I also saw where the age of the Mustelidae clade was quite old and also undergoing some revisions due to genetic information.

http://en.wikipedia.org/wiki/Mustelidae

quote:
Mustelidae (from Latin mustela, weasel), commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa.[citation needed] The internal classification seems to be still quite unsettled, with rival proposals containing between two and eight subfamilies. One study published in 2008 questions the long accepted Mustelinae subfamily, and suggests that Mustelidae consists of four major clades and three much smaller lineages.

The Mustelidae in general are phylogenetically relatively primitive and so were difficult to classify until genetic evidence started to become available. The increasing availability of such evidence may well result in some members of the family being moved to their own separate families, as has already happened with the skunks, previously considered to be members of the mustelid family.

Mustelids vary greatly in size and behavior. The least weasel is not much larger than a mouse. At the other end of the scale, giant otter can measure up to 2.4 metres (7.9 ft) in total length and sea otters can exceed 45 kilograms (99 lb). The wolverine can crush bones as thick as the femur of a moose to get at the marrow, and has been seen attempting to drive bears away from its kill. The sea otter uses rocks to break open shellfish to eat. The marten is largely arboreal, while the badger digs extensive networks of tunnels, called setts.


That is quite a diversity of behavior, with each of the different behaviors being enabled by specific variations within this clade. We can posit a link between behavior and selection, with successful behaviors(1) enabling survival and reproduction.

When we look again at the Newfie dog we see more adaptation than just the webbed feet.

quote:
Newfoundland (dog)
The Newfoundland is a breed of large dog. ... Newfoundland dogs excel at water rescue/lifesaving due to their muscular build, thick double coat, webbed feet, and innate swimming abilities.[3]

The Newfoundland's extremely large bones give it mass, while its large musculature gives it the power it needs to take on rough ocean waves and powerful tides. These dogs have great lung capacity for swimming extremely long distances, and a thick, oily and waterproof double coat which protects them from the chill of icy waters. The droopy lips and jowls make the dog drool.[2]

In the water, the dog's massive webbed paws give it maximum propulsion. The swimming stroke is not an ordinary dog paddle. Unlike other dogs, the Newfoundland moves its limbs in a down-and-out motion, which can be seen as a modified breaststroke. This gives it more power with every stroke.[2]


We also see "great lung capacity for swimming extremely long distances, and a thick oily and waterproof double coat which protects them from the chill of icy waters" and a "down-and-out motion, which can be seen as a modified breaststroke" swimming behavior. It is unlikely, imho, that the webbed feet, oily coat or swimming pattern were specifically selected by the breeders, as it is more likely that they selected for basic swimming ability or simply for a dog that was good for a cold marine coastal ecology.

These adaptations certainly enable a more active marine behavior than seen in most other dogs, which could easily maintain selection for even more active marine behavior.

Message 1: This is a feedback response system that is repeated in each generation:

Thus we see that an initial small novel trait due to random mutations can enable modified behavior that allows the carriers to move into a slightly different ecology. In that ecology the novel trait is beneficial, and this causes the feedback selection to maintain the trait and increase further adaptation to that ecology.

This fixes the novel trait in a breeding population, and can start the process of speciation or varietal diversification.

Traits like shorter legs and webbed feet are seen in many species (including human), however selection generally returns the population to more normal legs and feet.

Enjoy.

(1) - while meme is defined as "an idea, behavior or style that spreads from person to person within a culture" this is more of an enabled modification of existing behavior than a newly learned one.


we are limited in our ability to understand
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RAZD
Member (Idle past 296 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 15 of 314 (655720)
03-12-2012 10:54 PM
Reply to: Message 14 by RAZD
03-10-2012 8:51 AM


continuing
In Message 1 I asked

I could not find any examples of wolves with these characteristics, so are they novel features?

Creationists like to argue (pointlessly) that descendants of dogs will always be dogs (while evolution says the descendants will always be members of the dog clade), but what happens when these dog descendants develop novel features, like webbed feet?

According to the (adjective) definition of novel as something "not seen before; new" and as webbed feet do not appear to be a characteristic of wolves, then technically they are a novel feature in this clade (wolves and dogs), a derived trait developed by mutation and adaptation of an existing trait.

What if the finger\toe bones become elongated, so the webbing fills a larger area? That's just genetic variation, yes? Is that a novel trait?

What if the elongated finger\toe bones enable new behavior?

http://www.metrogaya.com/...ng-kalimantan-hewan-yang-kerennn

My favorite frog, (Rhacophorus nigropalmatus), commonly known as Wallace's flying frog.

quote:
http://bookbuilder.cast.org/view_glossary_full.php?op=ful...
Tetrapods
A group of animals with four limbs.

Most tetrapods still have four limbs, although there are many differences between the limbs. Here are a human arm, a dog's front leg, and a seal flipper.

So when we combine webbed feet with extended finger\toe bones and other continued adaptations for a coastal marine environment (lungs, fur, etc) do we end up with something that is not a dog?

quote:
The harbor (or harbour) seal (Phoca vitulina), ... found along temperate and Arctic marine coastlines of the Northern Hemisphere.

Skeleton

Again we see the homologies in the bones of the seal to those of dogs or wolves, typical of homologies for all mammals, with only a little (derived) modification of the arm and foot lengths. Is this what creationists mean by novel? (or do I have a sense of impending goal-post moving ... )

quote:
Bats are mammals of the order Chiroptera ...from the Greek ...- cheir, "hand"[2] and ...- pteron, "wing"[3]) whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly, and can only glide for short distances. Bats do not flap their entire forelimbs, as birds do, but instead flap their spread-out digits,[4] which are very long and covered with a thin membrane or patagium.


Townsend's big-eared bat, Corynorhinus townsendii

Again, the skeleton will show typical mammal homologies in the rest of the bones, and here we can see the homologous finger and arm bones through the thin webbed skin where the derived traits are the lengths of the bones.

Is this a novel trait?

It looks like nothing more than continued adaptation of webbed limbs to enable modified behavior, and perhaps open up ecological opportunities.

Is this not a major innovation?

Is this the result, accumulated over several generations, of normal evolution - the change in the frequency distribution and composition of hereditary traits within breeding populations, from generation to generation, in response to ecological challenges and opportunities - or is this something else, some other, perhaps major\significant\wondrous process?

Enjoy.

Edited by RAZD, : word order


we are limited in our ability to understand
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