Pharyngula

Friday Cephalopod: Face to face

i-856ea1d419881b6c3dd6c98dd62f8732-argonauta_nodosa.jpeg
Argonauta nodosa

Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.

Comments

  1. #1 Don Smith
    April 30, 2010

    Wow, an octopus camouflaged as a nautilus.

  2. #2 bbgunn071679
    April 30, 2010

    Argonauta nodosa looks like the next ‘South Park’ character.

  3. #3 Kieranfoy
    April 30, 2010

    Dunno why, but it looks like a Communist.

    Dirty Commy Squid!

  4. #4 Dave Dell
    April 30, 2010

    There’s an uncanny resemblance to Christopher Walken. Perhaps the diver needs more cowbell.

  5. #5 stevieinthecity#9dac9
    April 30, 2010

    More like Markie Mark.

    “Hello, Octopus. Nice to see you. Say hi to your mother for me.”

  6. #6 Glen Davidson
    April 30, 2010

    I’ve always like the wrap-around face. It improves close-ups.

    Glen D
    http://tinyurl.com/mxaa3p

  7. #7 mommimus-prime
    April 30, 2010

    I’d be very afraid. It looks too much like Starro .

  8. #8 Rick McWilliams
    April 30, 2010

    The cephalopod argonauta is a vey cool creature. There is a very thin membrane that is associated with two tentacles that can unfold and cover the entire shell. This membrane has many fast acting photophores that can change color from blue to orange to red in wave like patterns. When swimming the tentacles are very neatly stowed over the opening and look something like tire tread. These swim fast about 1m/s. They seem to hide their colors when irritated. I think that the diver is just about to get inked.

  9. #9 Jordan Bigel
    April 30, 2010

    Uh, can someone please help me debunk what I suspect is a rediculous claim – to wit:

    “just read: human males have more genes in common with male chimpanzees (99.4%) than we do with female humans. Could this be true? Probably.”

    A friend sent this to me, neither of us can say for sure, but I am pretty certain this is untrue. Please give me a reference to debunk this claim!

    Thanks!

  10. #10 PZ Myers
    April 30, 2010

    That is awesomely stupid. It takes real brilliance to come up with something that idiotic.

    I can’t think of a reference to debunk it, just like I can’t think of a reference to debunk the claim that the scent of a rose is loud green. The words don’t fit.

    The guy doesn’t understand the basic concepts. On one level, you can say that both chimps and humans have a gene for UDP Glycosyl Transferase…but the key thing is that the sequences of all those genes vary by a small amount from each other because they’ve diverged over evolutionary time. In fact, when you take that gross view and ignore the sequences involved, humans and mice have the same genes (we only differ by a few hundred novel genes, out of 20,000 total genes). It’s looking at the wrong thing.

    We have human gene sequences, both male & female. Chimps have chimp sequences, both male & female.

  11. #11 Jeep-Eep
    April 30, 2010

    It’s an octopus trying to be an ammonite!

  12. #12 Joel
    April 30, 2010

    Those eyes look fake to me.

    .
    .
    .
    .
    .
    .
    .
    That shade of blue just does not appear in nature.

  13. #13 Ing
    April 30, 2010

    RING RING “Hello?”

  14. #14 jcmartz.myopenid.com
    April 30, 2010

    Staring contest!

  15. #15 Caine, Fleur du mal
    April 30, 2010

    Argonauta nodosa, wow. Stunning beauty.

  16. #16 MadScientist
    April 30, 2010

    That cephalopod doesn’t seem to find its snack very apetizing.

  17. #17 Joel
    April 30, 2010

    “just read: human males have more genes in common with male chimpanzees (99.4%) than we do with female humans. Could this be true? Probably.”

    I got my degree in English, so I’m not qualified to say anything on the subject. But I will anyway, since that’s what English majors do. Plus, I asked Professor Google and he says that based on resent research, this is wrong to the tune of 180 degrees.

    The critical point is that the mysterious author of those statistics has attempted to equate human males with chimpanzee males with human females, and has come up with some mathematical tricks based on the differences between human Y-chromosomes, chimpanzee Y-chromosomes, and human X-chromosomes. It’s an apples to oranges to bananas comparison.

    The X-chromosome is bigger than the Y-chromosome, so it has more DNA content. Since females have 200% X-chromosome material, compared to human males who have 100% X-chromosome material and 100% Y-chromosome material, human females have some extra DNA that human males don’t have. By volume alone, the males of each species are pretty darned close, the females of each species are pretty darned close, and the females of each species are slightly ahead of the males of each species (and also males of the other species). That’s a purely quantitative argument though, and says nothing about qualitative differences in genetic makeup across species and gender.

    (Qualitatively, males have 100% of the DNA content that females have, plus some extra uniquely male DNA that is highly specialized in its role of sex determination. A large number of Y-only genes deal directly with sperm production. So females have more DNA, but males have more genetic content — but only to the extent that they need extra genetic content in order to be reproductively male in the first place.)

    Now, if the Y-chromosome were genetically very stable compared to the X-chromosome, then there might be truth in the qualitative hypothesis that the “maleness” part of our human DNA has changed very little since our last common ancestor with chimpanzees. The fragile and sensitive Y-chromosome would resist change and thus would be more nearly equal to our genetic cousins.

    However, that does not appear to be the case. A January 2010 paper published in Nature discusses the recent mapping of the chimpanzee Y-chromosome, which has enabled scientists to directly compare human and chimpanzee DNA more closely than ever before. They have found that in fact the Y-chromosome is a very rapid evolver, and experiences faster genetic change than any other human or chimpanzee chromosome. In fact, the human and chimpanzee Y-chromosomes differ by an astounding 30%, compared to only about 5% for our genomes taken as a whole. There has been a large amount of variation in Y-chromosome material in both species in the relatively short time since our ancestral lines diverged.

    (They hypothesize that this is due to sperm competition, which makes intuitive sense to me. Sperm must compete vigorously not only with their own brothers and sisters, but also with sperm deposited by other males, if they are to win the reproductive race and successfully develop into diploid beings. It is the most intensely competitive phase of human reproduction, and only one spermatozoon among millions can claim the prize. It is a ruthlessly fierce laboratory for pure, unadulterated natural selection.)

    Since the Y-chromosome of both humans and chimpanzees is changing more rapidly than any other of our chromosomes, including the X-chromosome, then we can say that human males are more distantly related to chimpanzee males than human females are to chimpanzee females.

    http://www.nytimes.com/2010/01/14/science/14gene.html

    I tried to do a search to find out where the 99.4% number came from, but it was mostly fruitless. The number seems to come from the observation that humans and chimpanzees share 99.4% of critical DNA sites, and is most often used to argue for placing humans and chimpanzees in the same taxonomic genus. I can’t find anything that links the quoted number to a gender difference.

  18. #18 Stanton
    April 30, 2010

    Mommy Argonaut is pregnant?

  19. #19 Yunomi
    April 30, 2010

    Wow. Just…wow. I didn’t know such a thing existed, so Googled it, and found another beautiful picture of one in your own archives! Feb.17, 2006. A purple and gold one. That would be a Mardi Gras Argonaut, yes?

  20. #20 bruder
    May 3, 2010

    hello. the human/chimp quote came from me and was never intended to be a public comment. I posted it for my friends to discuss on my facebook page. I didn’t mean to spread false or misleading information. In examining this claim i think it’s important to consider the context.

    The original source for information is the 2007 book ‘Boys Adrift’ by Dr. Leonard Sax MD PhD. The actual quote is on page 24 and reads:”As a human male, I share many genes with a male chimpanzee that I do not share with any human female. Recent work comparing the human genome with the chimpanzee genome suggests that I share 99.4 percent of my genes with a male chimpanzee — slightly more than I share with a female human. This does not mean that I am in general more like a male chimpanzee than I am like a female human. But in certain specific ways — for example, in the way I see, hear, and smell — I may actually have more in common with a male chimpanzee than I have with a human female. And those areas of commonality are important to understand.”

    The following references are sited:

    Journal Nature September 2005: “Initial sequence of the chimpanzee genome and comparison with the human genome” http://www.nature.com/nature/journal/v437/n7055/pdf/nature04072.pdf

    Proceedings of the National Academy of Sciences May 2003, “Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: Enlarging genus Homo.” http://www.pnas.org/content/100/12/7181.full.pdf+html

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