The Mystery of Evolution: One Down

My kids just informed me that they have seen an okapi evolving, or transitioning into a zebra

Okapi’s stripes appear to be no doubt the same as zebra’s…

Zebra, Equus quagga, Masai Mara Reserve, Kenya : Stock Photo

Well, at least we have one example of species transitioning into another…out of 10 billion and this one looks like a stunner….

I have to run!

I’ll fill in the rest when I get back…

Update!

It turns out that okapi is considered to be more closely related to giraffe than to zebra…if at all…That is surprising…because okapi and zebra do look alike just okapi is missing some stripes…No wonder my kids fell for it…as did some experts…

“…The okapi and the giraffe were assigned to the same order (Artiodactyla) because they both have cloven hooves, and to the same family (Giraffidae) because they share certain distinctive features: Both have large eyes and ears, thin lips and a long, extensible tongue that allows them to lick their entire face (even the ears); their backs slope upward from rump to withers; they also share the same dental formula: ( i 0/3, c 0/1, pm 3/3, m 3/3) × 3 = 32. Both, unlike any other mammal, have molars with rugose enamel and bony horns that remain covered with skin throughout life (Nowak 1999, vol. 2, p. 1085).

Yet the rump and legs of an okapi are covered with black-and-white stripes exactly like those of a zebra. Perhaps, then, if okapis had solid hooves instead of cloven ones, they would be classified as perissodactyls (Order Perissodactyla) and would be considered more closely related to zebras than to giraffes. An okapi is about the same size as a Burchell’s zebra.

The chromosome count of an okapi is also like that of a zebra, to which it is not supposed to be related, and unlike that of a giraffe. Giraffes have 30 chromosomes (Taylor et al. 1967; Hösli and Lang 1970; Koulisher et al. 1971), whereas okapis have a variable chromosome number of 44-46, depending on the animal in question; most seem to have 2n = 45 (Ulbrich and Schmitt 1969; Hösli and Lang 1970; Koulisher 1978). The chromosome number of Grevy’s zebra is 2n = 46 and plains zebras have 2n = 44 (Benirschke and Malouf 1967). Variation in chromosome count is itself unusual among mammals, but common in hybrids…”

The 14-16 chromosome difference between giraffe and okapi is striking isn’t it?

117 thoughts on “The Mystery of Evolution: One Down

  1. Mung,

    Oh good. Everything changes. Except when it doesn’t. I love this evolution bullshit.

    Everything changes, including, apparently, your opinion on whether evolution is ‘bullshit’ or not.

  2. Hey, chromosome number varies. Biologists were hitherto unaware of this, thanks Creationists! I suspect another rewriting of the theory of evolution is on the cards.

    Anyhoo … don’t know if anyone has mentioned muntjacs.

  3. J-Mac: Most of us can gather that the update makes it worse… for you…unless you can prove the miraclevolve disappearance of 14-16 chromosomes…in the process of miraclevolution…

    That took 5 minutes of googling and confirmed my suspicion that that has mostly occurred through Robertsonian translocations :

    It is reported that the giraffe has a karyotype of 2n = 30 (Taylor et al., 1967; Hösli and Lang, 1970; Koulisher et al., 1971), and that Robertsonian translocations are primarily responsible for interspecific karyotype differences between giraffe and okapi (Okapia johnstoni, the other extant species in Giraffidae) (Petit and De Meurichy, 1992)

    Now, since you have this amazing insight into biology and do not require any reading or learning, I assume I don’t have to explain what Robertsonian translocations actually are, do I?

    Right?

  4. A favourite example of karyotype evolution is the distribution of acrocentric and metacentric chromosomes within mammalian genera. It is nonrandomly distributed. Most species are either ‘mostly acrocentric’ or ‘mostly metacentric’ – centromeres near the ends or in the middle. An evolutionist might ask the question ‘why?’ (The Creationist, meanwhile, more than content with ‘That’s Just The Way God Planned It’ – altogether now!).

    The hypothesis is that the polarity of female meiosis frequently reverses. In mammalian female meiosis the haploid outputs comprise one germline gamete and three dead-end polar bodies per diploid, and the polarity determines which of these haploids is the ‘winner’. There is no especial advantage or disadvantage to having one polarity or the other, so the change can drift to fixation. But once reversed, heterozygous chromosomes with more or fewer centromeres than their homologue (depending on current polarity) find themselves in the gamete more frequently, and so increase. This biases the pattern, hence the absence of the expected middle-ground situation hovering around half-and-half of each.

    There is independent support for this hypothesis. Only evolution (also known as ‘bullshit’, ‘ bs’, ‘fairy tale’, or ‘the gibberings of the Darwin faithful’) has so far managed to find an explanation for this curious pattern.

  5. Corneel,

    Yeah, the whole world of selfish elements is fascinating, and rather inexplicable outside of evolution. I recommended Burt & Trivers’s ‘Genes in Conflict’ to Mung. He bought it, even though presumably he doesn’t buy it, if you know what I mean. 🙂

  6. Bugger, I got my links the wrong way round. The first paper should have been Pardo-Manuel de Villena & Sapienza, the second the B chromosome paper. Ah well, too late now.

  7. J-Mac: I can even claim that my ass is evolving into ears…

    I believe this transformation is the other way around, and is much more extensive than merely your ears.

  8. J-Mac:

    I can even claim that my ass is evolving into ears…

    Rumraket:

    I believe this transformation is the other way around, and is much more extensive than merely your ears.

  9. J-Mac:
    Robert Byers,

    If I had known you were going to expose the evolution theory like that, I would have never even bothered to write this OP…
    BTW: Robert, do you usually finish drinking at this hour? I noticed that most of your comments are around this time or later and all indicating intoxication…

    At least i have subject influence.
    Whats wrong with what i said?
    I think I’m right and made good points.
    However if drunk one would think that!
    Actually i don’t drink at home since i don’t want to pay for it. Only free booze please!

  10. Joe Felsenstein: Yup, I own it, and I’m not selling it.

    (OK, that was probably an autocorrect error for “owe”)

    I stand by my statement (which was to agree with, I think, dazz) that all species are evolving, and given enough time will change enough to be considered new species.For example, ultimately they will be different enough that, if they encountered that ancestor, they would be reproductively isolated from it.

    And no, we don’t need to know what the species is going to become in order to say that.It will become increasingly different.

    And although it is not absolutely impossible that an okapi will turn into a zebra, so much would have to happen very precisely that it is astronomically improbable, an event that would not happen even once in the whole history of the Universe.

    Oh, and for the people whoare talking about a gene for stripes, you need to read papers and a book by Jim Murray, a former colleague of mine, who has worked out much of the determination of color patterns by diffusion of color morphogens. See this Scientific American article.

    Thats interesting.
    ALL SPECIES are evolving hmmm.
    Is this what modern evolutionism teaches.
    I understand they teach, under PE/Gould influence, that species etc ARE NOT EVOLVING. Rather they are always in statis or fixed body plans AND THEN a geographically etc segregated minor breeding pairs are forcede to adapt and so selection on traits aND then this new population takes over with the extinction of the previous body plan population.
    I don’t think they teach species are all, and always, evolving before our eyes.
    That was Goulds whole point about the fossil record.

    You need to back this up. How would this work anyways. Are white tail deer evolving in canada and mexico and France in same or different directions??

    Its okay if genes are the reason for colours. however the determination for colours is from the influence of nature. not that colours have a mind of their own.
    In fact i do see colours as a innate thing already in the body plan systems and triggered by outside influences.
    Colour morphogenes needs a guiding hand .

  11. Robert Byers: At least i have subject influence.
    Whats wrong with what i said?
    I think I’m right and made good points.
    However if drunk one would think that!
    Actually i don’t drink at home since i don’t want to pay for it. Only free booze please!

    Thanks Robert…
    I thought maybe you and keiths were drinking buddies coz you both start writing at the same time and both have very similar coherence and writing level…The only difference is that you are the soft one and he is the angry one…
    Since you are not buddies with keiths, please drop him a line as it looks like everybody but you and fifthmonarchyman have him on ignore… 😉

  12. Joe Felsenstein: I stand by my statement (which was to agree with, I think, dazz) that all species are evolving, and given enough time will change enough to be considered new species.

    I’m glad that you stand by your statement that ALL 10 BILLION SPECIES ON EARTH ARE EVOLVING AND TRANSITIONING INTO OTHER SPECIES…Harshman was a bit surprised by your statement of 10 billion…I’m not sure why…

    So, how will you be able to prove that those species are changed enough to be considered different species?

  13. John Harshman:
    I would like to repeat my statement that this post is an abuse of posting privileges. And the “update” makes it worse.

    This is yet another of “the new site administrator’s” complaints…Harshman says he didn’t complain about the bulk of my OPs…I guess it all depends what one means by bulk…;-)

Leave a Reply