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Author Topic:   Ring Species!!
drpepperandmilk
Junior Member (Idle past 5270 days)
Posts: 4
Joined: 08-19-2009


Message 40 of 50 (520121)
08-19-2009 1:26 PM


How are ring species evidence for upward change?
I'd like to know how the variation observed in ring species demonstrates the potential of MACRO changes, i.e. new major structures. The lack of ability/inclination in the converging groups to breed seems to indicate that significant information from a finite gene pool was lost, not gained.

Replies to this message:
 Message 41 by Coyote, posted 08-19-2009 2:16 PM drpepperandmilk has replied
 Message 42 by Dr Adequate, posted 08-19-2009 2:32 PM drpepperandmilk has replied

  
drpepperandmilk
Junior Member (Idle past 5270 days)
Posts: 4
Joined: 08-19-2009


Message 43 of 50 (520165)
08-19-2009 5:23 PM
Reply to: Message 42 by Dr Adequate
08-19-2009 2:32 PM


Re: How are ring species evidence for upward change?
ring species don't demonstrate that potential, the laws of genetics do
Mendel’s? How so?
and the fact that we know that it's happened.
You can’t substantiate a claim by saying you simply know something happened.
Which does it take more information to describe, one species or two species?
The sum of information I’m talking about is the total within each group, not the two end groups added together. Take the Ensatina salamanders in CA. Indeed there was variation from one group to the next in color, size, with the ability to breed with neighboring groups remaining intact, until the end groups lost this tendency and had their opportunities to breed basically cut in half. This is not necessarily a death sentence for the entire new species, but does not seem to be a micro step in a progressive direction. My original question phrased a bit differently: If this (ring species) is an example of how progressive changes occur in biological evolution, how do apparent small steps backward like this add up to big steps forward over time?

This message is a reply to:
 Message 42 by Dr Adequate, posted 08-19-2009 2:32 PM Dr Adequate has replied

Replies to this message:
 Message 46 by Dr Adequate, posted 08-19-2009 6:30 PM drpepperandmilk has replied
 Message 47 by RAZD, posted 08-19-2009 9:44 PM drpepperandmilk has not replied

  
drpepperandmilk
Junior Member (Idle past 5270 days)
Posts: 4
Joined: 08-19-2009


Message 44 of 50 (520168)
08-19-2009 5:40 PM
Reply to: Message 41 by Coyote
08-19-2009 2:16 PM


Re: How are ring species evidence for upward change?
Thanks for your welcome!
If we are defining species by any amount of visible change, or the more rigid criteria of sexual barriers, then yes, I would say that "ring species" result in new species. But to say this is what adds up to large scale descent from single cells to the vast array of life that we observe on earth now doesn’t make sense based on what we know and have observed.
the opposite [of devolution] is in fact what the evidence shows...
There is nothing that has been discovered in biology that prevents those two groups from evolving significantly from one another, including one or more of them evolving what you might call major structures not shared by the other. (The concept of "kinds," with no changes beyond some arbitrary boundary, is a religious belief, not a scientific principle.)
I think the assumption here, which leads to differing interpretation of the evidence, is that this process is naturally limitless and needs something to prevent it from evolving organisms beyond limitation. The arbitrary boundary in original kinds is not known, but I think it’s more reasonable to assume that a definitive boundary (certainly not arbitrary) exists rather that to assume it does not.

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 Message 41 by Coyote, posted 08-19-2009 2:16 PM Coyote has not replied

Replies to this message:
 Message 45 by Dr Adequate, posted 08-19-2009 6:18 PM drpepperandmilk has not replied

  
drpepperandmilk
Junior Member (Idle past 5270 days)
Posts: 4
Joined: 08-19-2009


Message 48 of 50 (520409)
08-21-2009 12:06 PM
Reply to: Message 46 by Dr Adequate
08-19-2009 6:30 PM


Re: How are ring species evidence for upward change?
acorns have the potential to grow into oaks
Seeds to trees: Have you really observed potential, or have you concluded potential by what you’ve observed? We can repeatedly test and observe in the present a seed producing a tree, and then be satisfied that a seed grows into whatever kind of tree the seed originated from. Over successive generations, limited varieties appear. This is not the same proposition of common descent of that tree and all life, which you can only hypothesize without observing it in the past or anything like it in the present.
If you are going to count speciation as a step "backwards", what are you going to count as a step forwards"
The much celebrated arrival of the salamander to new species status is not the step backwards. It's the fact that what earned him that status is fewer options for breeding. "Forward" would be the ability to breed with other species of salamander with which he had been previously unable. Or a significant increase in body size. Or development of scales for protection. Or wings. Big teeth. Lose the cumbersome tail and walk upright. Of course, all this would take way to much time to be able to completely observe, yet you still assume that it has occurred.
I don’t know for certain that the end taxa of the ring species refusing to breed with each other is from a loss of genetic information by mutation or otherwise. My point was that it seems at least a small step backwards in an evolutionary scheme, and my original question (in response to the top post in this thread proposing "Is there a better proof for evolution [than] the ring species?") is how this demonstrates the potential of big changes forward. You did state upthread that "ring species don't demonstrate that potential, so in a way you have answered. It's been suggested that I visit a different thread for discussion of "new major structures" so I may do that. Thanks for the discussion, it was interesting.

This message is a reply to:
 Message 46 by Dr Adequate, posted 08-19-2009 6:30 PM Dr Adequate has not replied

Replies to this message:
 Message 49 by Theodoric, posted 08-21-2009 1:04 PM drpepperandmilk has not replied

  
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