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Results 41 to 48 of 48
  1. Default


    0 Not allowed!
    Quote Originally Posted by Fishguy2727
    True, if your definition of a species is a group of animals that can interbreed to produce fertile males, then obviously there will be no exceptions of different species producing fertile males.

    Macaws can interbreed and produce fertile male offspring and those are between species, not subspecies.

    Genetic evidence shows that the red wolf is actually a result of the grey wolf x coyote hybrid.

    Mbunas and peacocks can cross to produce fertile males.

    All this is why many biologists do not believe in the idea of a species, at least not the way we currently think of and define it. It is a circle: well, if peacocks and mbunas can produce perfectly healthy and fertile offspring then are they really different species? The answer is still yes to most scientists. In my Evolution class we went in to all of this and what scientists currently usually go by is the presence of natural breeding barriers. These can be behavioral and not just genetic (naturally in Lake Malawi subtle behavioral and visual differences allow all the different 'species' of mbunas and peacocks to find and mate with each other). Since Biology is a study of life in NATURE if the animals do not interbreed in nature then it doesn't matter what they will do when locked in cage with a member of the opposite sex of a different natural species.

    So for a much simpler and easier to deal with definition of a species, a species of animal is usually defined as a group of animals that will NATURALLY interbreed to produce fertile offspring.

    But I do agree, as humans we want to look at nature as if it is done and it is just our job to go out into it, look at it, and understand it. Unfortunately nature is not done and species are still changing, so they won't fit in our pigeon holes of ideas that we consider species
    .
    Yes, good review you've given. I'm not sure when you took your evolution class but we discussed this debate when I took it as an undergrad back in '82 or so. Our professor at that time professed he suspected the concensus definition of species - i.e. groups which won't breed in the wild even if they genetically couldn't - may change as more knowledge of genetics accumulated.

    I have to give you by the common definition of hybrid such examples of various color/feather morphs of machaws interbreeding would be "hybrids" but I'd have to ponder by this definition what's the difference between 'species' and 'sub-species'? Among some invertebrates the only way to define species is to ascertain if two groups can produce viable male breeders (There has been recent research on Drosophila yielding new info as to the whys of male hybrid sterility http://academic.research.microsoft.c.../6448402.aspx). It is strange how male sterility is a common trait in hybrids across the spectrum of life though even among vertebrates sex isn't determined by the same pairing of XY and XX but the formation of the male gamate undergoes a homologous mitosis.

    The debate in anthropology as to whether neandertals were a 'race' of H. sapiens or another species was somewhat settled through comparisons of neandertal DNA which found they had enough mutational differences to conclude any male offspring resulting from a cro-mag and neandertal union would be a sterile hybrid therefore making neandertals a separate species, designated H. neanderthalensis .

    I'm kind of foggy on the hybridization leading to speciation hypotheses. Speciation is caused in good part by isolation of gene pools so any speciation forming from an interbreeding of two previously for a time non-breeding groups would still require a subsequent isolation of that 'hybrid' from either parent group.

    But I digress....:-)

    My original post was about how I used to have people argue with me that blood parrot cichlids were just inbred deformed creatures and how I knew they were in fact hybrids due to the sterile males.

    I'm OK with hybrids, in fact hybrids can sometimes be hardier than either of their parent species, but I'm not so enthusiastic about inbreeding.
    "In order to punish me for my contempt of authority the authorities have made me an authority myself" - Albert Einstein.

  2. #42

    Join Date
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    Merry Christmas - Abbeys_Mom Great advice thanks - nraposa Thanks for helping me with my cichlids - Drumachine09 Always good answers - Lady Hobbs You dont have enough gifts. - Drumachine09 
    Thanks for your help again. - Lady Hobbs goodbye reptileguy....hello Fishguy - Lady Hobbs For always giving me great answere's on my PM's. Thanks for all the help! - cocoa_pleco Thanks For Your Help & Knowledge! :) - MeganL3985 For weakening me against axolotls!!!!!!! - Nick_Pavlovski 
    I am baking today and figured I'd share...Thanks for Always Helping when it's needed! - **AquaQueen** For recommending Fluvals and Stealths - Lady Hobbs Merry Christmas :) - MeganL3985 Merry Christmas! - RichBowyer Thanks for the hikari help - Billythefish 
    No Message - LORENZO Merry Christmas - Northernguy merry christmas.. a fellow fishnutter. - LORENZO merry christmas.. a fellow fishnutter. - LORENZO Merry X-Mas!! - The Red Severum 

    Default


    0 Not allowed!
    I took it about two years ago, I graduated in '08.

    It all makes sense, but it was never brought up in my Evolution class so I don't know what the current exact concensus is among the pros of today.

    It all makes sense though. And it is definitely true that just because 100 years ago we decided that cerain types of macaws were different species doesn't mean they are not truly a wide range of subspecies (after all it is mostly color which is usually the first thing to change).

    The Red Wolf is supposed to be a good example of a species produced by hybridization. If interested you may want to check out some more info on them.

    Thanks for all the info.
    Aquarist since 1995
    Biologist
    Owner: Aquarium Maintenance Company
    Brian's Aquarium Care: Articles about many aspects of aquarium care.

  3. Default


    0 Not allowed!
    Quote Originally Posted by Fishguy2727
    The Red Wolf is supposed to be a good example of a species produced by hybridization. If interested you may want to check out some more info on them.
    I was trying to follow with keen interest what was happening with the hybridization between displaced polar bears and brown bears but haven't found much further info, perhaps there are no funds for research of the phenomenon. I have to wonder if the resulting male offspring are sterile. I remember some commentator on CNN asking if a new species of bear would arise from these unions. I'd guess probably not in any event since there'd be no isolation mechanism, apparently the only one between brown and polar bears was proximaty.

    Interesting stuff

    One of the grandest proofs of evolution in progress are the genetic differences between various Genera of the Cichlidae. It is demonstrable they share common ancestry, yes many can produce fertile offspring but some have been separated long enough that their divergence from separate accumulation of mutations produce hybrids with sterile males and sometimes even no offspring without human manipulation.

    I sometimes argue with young earth creationists and so called "Flood Geologists" and they sometimes argue such Families of animals aren't evidence of evolution since they are just divergent from a single biblical "Kind" though the definition of "Kind' shifts in accordance with whatever they are arguing at the moment. They have no explanation for the phenomenon of sterile offspring from hybridization. If horses and donkeys are not of one "Kind" why can they produce offspring at all, if they are of one "Kind" why can they not "breed true"?
    "In order to punish me for my contempt of authority the authorities have made me an authority myself" - Albert Einstein.

  4. Default


    0 Not allowed!
    Good article.. I must say I dont agree with the whole goldfish thing..them being balloon shaped and big bubbles i find it very sad for them and unhealthy. I dont have a problem with hybrids though..not if its just 2 fish but i think its bad when its forced

  5. Default


    0 Not allowed!
    haha think about it were all hybrid whites blacks latino asian

  6. Default


    0 Not allowed!
    For myself I let nature take it's course with a few exceptions, I don't allow guppies in with my Endler, we have enough of those LOL and I don't support altering fish by dying, injecting or warping Ie: Blood Parrots, but I do play God a bit, I look for oddball fish like my Dwarf Powder Blue Gourami, who doesn't have any red stripes to him just a red edge to his fins and hope to find a mayching female without any red just to carry on the odd look, or my Scarlet Krib male who has a scarlet female and a regular female, the gambusia female I raised with Endlers who is currently pregnant with endler/gambusia something, hopefully fertile LOL but honestly as long as your not shoving your fish into vats of acidic colors or binding their bodies does it matter? But this is just my opionion

  7. Default


    0 Not allowed!
    Quote Originally Posted by Fishguy2727
    Many people are now familiar with ligers, the resulting offspring between a male lion (Panthera leo) and a female tiger (P. tigris). The offspring are fertile.
    Ligers are the result of captive breed and will not occur natural since both cats are geographically different and separate species. Thus offspring will be and are infertile along with other genetic defects that give them shorter lifespans.

  8. #48

    Join Date
    Aug 2006
    Location
    Northern Virginia
    Posts
    7,284

    Awards Showcase

    Merry Christmas - Abbeys_Mom Great advice thanks - nraposa Thanks for helping me with my cichlids - Drumachine09 Always good answers - Lady Hobbs You dont have enough gifts. - Drumachine09 
    Thanks for your help again. - Lady Hobbs goodbye reptileguy....hello Fishguy - Lady Hobbs For always giving me great answere's on my PM's. Thanks for all the help! - cocoa_pleco Thanks For Your Help & Knowledge! :) - MeganL3985 For weakening me against axolotls!!!!!!! - Nick_Pavlovski 
    I am baking today and figured I'd share...Thanks for Always Helping when it's needed! - **AquaQueen** For recommending Fluvals and Stealths - Lady Hobbs Merry Christmas :) - MeganL3985 Merry Christmas! - RichBowyer Thanks for the hikari help - Billythefish 
    No Message - LORENZO Merry Christmas - Northernguy merry christmas.. a fellow fishnutter. - LORENZO merry christmas.. a fellow fishnutter. - LORENZO Merry X-Mas!! - The Red Severum 

    Default


    0 Not allowed!
    That is incorrect. They are fertile. And the parents being from geographically isolated areas does not inherently make the offspring sterile. Keep in mind they are from the same Genus (closer related than many other known hybrids).

    I never said they were natural.
    Aquarist since 1995
    Biologist
    Owner: Aquarium Maintenance Company
    Brian's Aquarium Care: Articles about many aspects of aquarium care.

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