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Author Topic:   Dogs will be Dogs will be ???
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 297 of 331 (654147)
02-27-2012 8:54 AM
Reply to: Message 290 by Chuck77
02-27-2012 12:36 AM


Re: micro and macro
Hi Chuck77
Definition two is a little confusing. One form to another that are simliar? (I will read the whole page as you recommend).
I agree that it is not the best wording, but I believe what they are talking about there is the arbitrary speciation that I described, seeing as they place it before speciation and the generation of diversity.
Another resource we can look at is Berkeley's website:
quote:
An Introduction to Evolution
The Definition:
Biological evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations). Evolution helps us to understand the history of life.
Here "small scale evolution" is the microevolution as before, and "large scale evolution" involves speciation events and arbitrary speciation changes accumulated over many generations.
They go on to discuss nested hierarchies and have many pages of followup material -- excellent reading that you can take a bit at a time. This was developed by the biology department to be a resource for schools to teach evolution, sort of an on-line textbook.
Ok. I think I understand. So a wolf for instance passes down herditary traits and maybe 4 generations later a species can look entirely different form the wolf? It's actually a new species. Micro evolution right?
Yes microevolution, but not necessarily a new species. Wolves to dogs is a good example here: we have a lot of changes that have accumulated and so we make the arbitrary decision to classify dogs as a subspecies of wolf: Canis lupus familiaris (where the third name identifies a variety within the species.
If all we had to go on were bones in a fossil record we would likely make it a new species classification, Canis familiaris for example. As Crash said, these identifications are for our use and don't really affect the nature of two animals breeding or attacking on another (think wolf and chihuahua).
But yes, microevolution leads to speciation, both arbitrary and discrete.
What do you mean by daughter population? Females in the area?
So in order for this to take place a lot of factors are involved mainley location and the daughter population in that area?
It's just the accepted terminology for a breeding population that is an offspring from another breeding population, just as a daughter is the offspring of a parent.
When a (parent) population divides into two different areas they can take on different evolutionary traits to adapt to those areas, and when those populations become isolated from one another we call them daughter populations, even though there are males and females involved.
Speciation seems important. I always thought speciation was two of the same kind (until I get a better grasp of everything I hope you don't mind me using the word kind) but different species reproducing? Like say a sparrow and a robin? Both birds...different species? Is that speciation or does it go deeper than that?
Yes speciation would result in two species in the same clade\kind, the same genus (ie first name same, second name different). Yes sparrows and robins are different species, but a little more distantly related than recent speciation event species would be.
Lets look at how similar the daughter populations can be before speciation occurs:
quote:
The greenish warbler ring species
Greenish warblers (Phylloscopus trochiloides) inhabit forests across much of northern and central Asia. In central Siberia, two distinct forms of greenish warbler coexist without interbreeding, and therefore these forms can be considered distinct species. The two forms are connected by a long chain of populations encircling the Tibetan Plateau to the south, and traits change gradually through this ring of populations. There is no place where there is an obvious species boundary along the southern side of the ring. Hence the two distinct 'species' in Siberia are apparently connected by gene flow. By studying geographic variation in the ring of populations, we can study how speciation has occurred. This unusual situation has been termed a 'circular overlap' or 'ring species'. There are very few known examples of ring species.
Map of Asia showing the six subspecies of the greenish warbler described by Ticehurst in 1938. The crosshatched blue and red area in central Siberia shows the contact zone between viridanus and plumbeitarsus, which do not interbreed. Colors grade together where Ticehurst described gradual morphological change. The gap in northern China is most likely the result of habitat destruction.
Plumage Patterns
West Siberian greenish warblers (P. t. viridanus) and east Siberian greenish warblers (. t. plumbeitarsus) differ subtly in their plumage patterns, most notably in their wing bars, which are used in communication. While viridanus has a single wing bar, plumbeitarsus has two. Around the southern side of the ring, plumage patterns change gradually.
Song
Male greenish warblers are very active singers, using song both to attract females and to defend their territories. Each male has a repertoire of song units, and songs are made by stringing together units in various ways. There is much geographical variation in both the song units and the rules by which units are assembled into songs.
There is a clear gradient in song characteristics around the ring, with the northern forms viridanus and plumbeitarsus differing dramatically in their songs. By measuring song spectrograms from various populations and doing a statistical analysis to illustrate the variation, we produced the following figure.
Here we have five daughter populations of varieties of the Greenish Warbler, Phylloscopus trochiloides, forming a ring around the Tibetan high plateau, with four hybrid zones in between. The hybrid zones mean that the neighboring varietal populations, and the fact that these hybrids do not spread into either neighboring varietal population area means that they are not better adapted there. Thus we have limited gene flow between neighboring daughter varieties, with very very little gene flow between the end varieties.
Where these two end varieties overlap in Siberia they do not see each other as mating material and do not mate: they are reproductively isolated daughter populations. Without the other intermediate daughter varieties we would say that speciation has occurred.
Note that there is just a little bit of difference in plumage and just a little bit of difference in mating songs, but that is enough.
Note that this is a lot less variation than seen in dogs.
Would you call speciation micro or macro? This may already be obvious but some things are gonna go over my head here.
I would say that speciation is the boundary between micro and macro. Before speciation the breeding population shares the gene pool, while after speciation the gene pool is divided into two discrete pools. Once speciation occurs each daughter population then continues to evolve (via microevolution within their breeding population) and they frequently evolve away from each other (because they are isolated or to reduce competition if they interact). As time passes, they will continue to evolve generation by generation, in the manner discussed for arbitrary speciation, and, as the chances of similar mutations occurring being very very small, they become more and more distinct as separate species.
Another element of macroevolution that you will see mentioned is the formation of nested hierarchies. With a speciation event you have a parent population and then two (or more) branches of daughter populations.
                         |
                         ^ a
                        / \
                       /   \
                      /     \
                     /       ^ b
                  c ^       / \
                   / \     /   \
                  d   e   f     g
Here "a" "b" and "c" are speciation events, and they cause the nested pattern seen here. Thus speciation is a critical element of macroevolution, even though the evolutionary process is all microevolution (confused yet?).
Hmmm. Well sure. I mean if it were to happen there is no denying it right? Wouldn't there be a trail leading both to each other?
(For sake of argument I have to bring some things up that I don't yet agree with so don't take it as me believing it now but it will help the conversation go forward)
For instance we would see dog traits in the horse and horse traits in the dog? They look alike from a distance, both run on 4 legs...tails, no tails etc etc. Yeah I could go with it. So why aren't they in the same family you think? Are they that far apart? Even if they are that far apart what is to say to seperate them anyway?
The critter shown is an ancestor to the horse, although from appearances it is very similar to a dog, and their skeletons appear very similar. What we can do is walk through the evolution of the horse from this ancestor, using the variation within dogs as a metric for how much variation is allowable between ancestors along the way.
Thus we can keep within the boundaries of microevolution at each stage to then show the accumulated large scale macroevolution at the end.
We can take it as slow as you want.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


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This message is a reply to:
 Message 290 by Chuck77, posted 02-27-2012 12:36 AM Chuck77 has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 299 of 331 (654150)
02-27-2012 9:26 AM
Reply to: Message 293 by Chuck77
02-27-2012 1:49 AM


Re: kinds and clades
Hi again Chuck77,
So could they actually mate at one time?
Yes and no. At one time in the distant past they shared a common ancestor, a parent population that divided into two daughter populations, one became placental mammals and one became marsupial mammals.
What you are seeing are two modern species that did not exist back then.
Are they are analogous? In contrast to homologous?
ABE: The above statement about analogous and homologous was from searching for "convergent evolution". This is what I found:
Excellent. They have analogous traits, and this is why they appear so similar at first.
Just as the fox and the cat have analogous traits as well as homologous traits ... the homologous traits are those they share because they are both mammals and descended from a common (placental) mammal ancestor, while the analogous traits involve size and body shape that make them seem similar at first, but one has evolved from a canidae ancestor and the other from a felidae ancestor that are less similar.
So they don't have a common origin? The sugar glider and flying squirrel?
They do (according to the fossil record), but it was an ancient mammal or proto-mammal, before they divided into the two daughter branches of mammals.
Yeah, works for me.
                         |
                         ^ a
                        / \
                       /   \
                      /     \
                     /       ^ b
                  c ^       / \
                   / \     /   \
                  d   e   f     g
Here "a" would be the basal type for a "kind" would it not?
So far yeah. It seems it would. B and C would be other species of the "A" kind.
Excellent. We can also say B would be a different genus from C within the "A" family, while D, E, F and G are different species. This is why cladistics works better for me than traditional taxonomy in discussing kinds.
Yes. That sounds good. Clade then would the "kind" I am taking about. What I don't get is when A,B or C of that clade...then jumps, to D,E and F. That's where I get lost. How could they?
How could they genectically? Do you understand what I mean? Like I said to Huntard, i'm trying to find where my point of contention lies.
It's not a big jump, just another step of the same type: both B and C also form a clade for their descendants, D and E from C, F and G from B. D belongs to both the A and the C clade... and this would be similar to dogs, wolves and foxes all being of the same kind\clade as canids.
Yep, sounds good.
Good.
Yeah, it's a big question. I don't know.
Hmm, well a Wolf isn't a dog but is canine. No one would call a bunch of wolves roaming around in the fields a bunch of dogs if they knew they were wolves. So if the Wolf is "A" and a horse was "B" or "C" then sure. What's the difference.
Again, the picture shown is not of an ancestor for the wolf, but it is an ancestor for the horse. What we have here is a fossil ancestor to the horse that appears to be similar to modern dogs/wolves -- we can consider this an example of convergent evolution as the traits that are similar are analogous in their similarity (and homologous in being placental mammal traits).
What we can do is review this critter in comparison to the modern dog\wolf and see if it is more or less different than the variation seen within dogs.
We can take this as slow as you want.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


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This message is a reply to:
 Message 293 by Chuck77, posted 02-27-2012 1:49 AM Chuck77 has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 300 of 331 (654154)
02-27-2012 10:04 AM
Reply to: Message 294 by Chuck77
02-27-2012 2:29 AM


Re: moving forward: how much variation constitutes enough change
Hi again Chuck77,
Yes, it probably would now. One thing I would say/ask you RAZD is this: If the fox and cat are closer in changes than some dogs are why are they classified differently? Shouldn't they both be in either the canine or feline clade? Why are they not classified together while dogs who are farther apart in changes are?
The fox and cat are another example of convergent evolution, where branches with more diverse ancestors have offspring that take on similar traits in response to the ecological opportunities and challenges. The traits that make them appear more similar than wolves and tigers are analogous (size, bone length, etc).
                         |
                         ^ a
                        / \
                       /   \
                      /     \
                     /       ^ b
                  c ^       / \
                   / \     /   \
                  d   e   f     g
Ok. i'm confused a little. Why are you putting canine with feline in the same clade? Aren't they a little to close together?I thought we were saying clades (for understanding you better and me grasping it better) was a kind - so to speak. Are you putting feline with canine?
Shouldn't it be "A" wolf "B" dog "C" poddle...and so on down the canine clade? d,e,f,g,h...
Then totally seperate would be "A" lion "B" tiger" "C" cat?
We can do that, but there is also a common ancestor between canidae and felidae in the fossil record.
Where you want to draw your line for kinds is up to you.
Ok I see. I wonder why they are classified differently. Do you know what the bigger difference are within the dogs? Is it much more than +3?
The differences within dogs is defined as 0 so any plus is more different and any minus is less different.
I understand what you're saying. You're saying if I accpet wolf to dog (which has more changes in some than fox to cat) then I should accept fox to cat (different "kinds" tho less changes) who are classified differently?
Accept the possibility of fox to cat-like. Again we are talking about convergent evolution and the development of analogous traits rather than a strict one into the other evolution (which is more of a creationist concept than an evolutionist one).
I understand RAZD. I do and thank you for explaining it to me. I think tho, were moving a little fast. I'm not so sure I agree with the way the taxonomic catagories are set up. Tho i'm not sure it really matters. As crash said it's only to help guide us.
To answer your question about convergent evolution I can't right now. I need to understand more what convergent evolution is. Maybe our (my) definition of kinds ahould be expanded a little more.
We can take it as slow as you want. If you go to the Berkeley page on convergent evolution you will see some additional information:
quote:
Homologies and Analogies
Since a phylogenetic tree is a hypothesis about evolutionary relationships, we want to use characters that are reliable indicators of common ancestry to build that tree. We use homologous characterscharacters in different organisms that are similar because they were inherited from a common ancestor that also had that character. An example of homologous characters is the four limbs of tetrapods. Birds, bats, mice, and crocodiles all have four limbs. Sharks and bony fish do not. The ancestor of tetrapods evolved four limbs, and its descendents have inherited that featureso the presence of four limbs is a homology.
There is more information on that page and subsequent ones.
Do you think this could or did happen? Since one is marsupial and the other placental? So they are related(?) but not classified together? Genetically their very different right?
The fossil record shows they have a common ancestor. They are classified together under mammalia. The genetics are about as different as we are from kangaroos.
How many changes do you think they are away from dog to wolf or fox to cat?
Lots. Many many generations. The common ancestor is back at the original formation of the mammal clade from reptiles, and predates the extinction of the dinosaurs.
ABE(again): RAZD I skipped over this because I didn't understand what your meant:
So you are asking for a larger degree of change than just from one kind to essentially be similar to another, yes?
The development of something that did not exist previously in the fossil record perhaps?
Such as evolving from something like a dog into the modern horse?
What do you mean?
It is common for creationists to ask for evidence of the evolution of something new that did not exist before, and it's a question of degree again, on how much change needs to be shown by the fossil record.
This is going in the opposite direction from convergent evolution.
Again we can take this as slow as you want.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


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This message is a reply to:
 Message 294 by Chuck77, posted 02-27-2012 2:29 AM Chuck77 has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 305 of 331 (654416)
03-01-2012 9:08 AM
Reply to: Message 304 by Chuck77
03-01-2012 1:35 AM


Hi Chuck77,
... I need to do some reading before moving forward here I think. ...
Good plan. If you have any questions you can bring them here.
I wanted to let you know i'm still looking to participate here and will respond to your posts soon.
Take your time, we will await your return.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 304 by Chuck77, posted 03-01-2012 1:35 AM Chuck77 has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 328 of 331 (656269)
03-17-2012 11:42 AM
Reply to: Message 321 by Chuck77
03-16-2012 4:09 PM


Re: kinds and clades
Hi Chuck,
It seems we are getting away from the Dogs will be Dogs topic into a discussion of clades and kinds.
Perhaps we should start a new thread?
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


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This message is a reply to:
 Message 321 by Chuck77, posted 03-16-2012 4:09 PM Chuck77 has replied

Replies to this message:
 Message 329 by Chuck77, posted 03-20-2012 3:43 AM RAZD has replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


(2)
Message 330 of 331 (656566)
03-20-2012 3:47 AM
Reply to: Message 329 by Chuck77
03-20-2012 3:43 AM


Re: kinds and clades
Hi Chuck77,
Nothing to be sorry about -- that's how learning progresses, by following your interests.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 329 by Chuck77, posted 03-20-2012 3:43 AM Chuck77 has not replied

  
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