Spiders have transparent blood.
I was just browsing through uselessknowledge.com and saw this fact. Is it true? What makes it diffrent from ours?
Transparent? Not really. Maybe it appears that way in some cases. More usually it tends to be a bluish color. That’s because instead of hemoglobin, spiders use hemocyanin as a blood pigment. Which being copper-based instead of iron-based ( like hemoglobin ) oxidizes to a blue/green color instead of red.
- Tamerlane
Thanks Tamerlane,
So what’s the difference between hemoglobin and hemocyanin (besides one being copper based)
J’s Friend: Hmmm… Now we’re starting to venture to the edge or beyond of my limited knowledge on the subject 
. Let’s see now, cadging from an old Physiology text or three:
Hemocyanins - Copper-containing protein, carried in solution. Found in some Molluscs and Arthropods. Almost clear when deoxygenated ( there’s the source of that 
), pale blue when oxygenated.
Hemethyrins - Iron-containing protein, always in cells, non-porphyrin structure. All Sipunculids, some Polychaetes and Brachiopods. Almost clear when deoxygenated, lemon-yellow or violet-pink when oxygenated ( depending on type ).
Chlorocruorin - Iron-porphyrin protein, carried in solution. Four families of Polychaetes. Deep red/green
Hemoglobins - Iron-porphyrin protein. Carries in solution or in cells. Most widely distributed. All vertebrates except a few fish, all Echinoderms, some Molluscs, some Arthropods, some Annelids, Nematodes, Flatworms, some Protozoa, etc.
Relative advantages? Hemoglobins seems to be the most efficient in terms of oxygen transport. Hemocyanins ( often found in critters with pen circulatory systems ) seem to be very immunogenic ( A function of their large molecular size? ). Dunno about the other two 
. Chlorocruorin’s don’t seem to have been studied much and I can’t quite get what the relative advantage any of the non-Hemoglobin’s have over Hemoglobin in most cases. Maybe there’s none and the move to Hemoglobin occurs under selective pressure lacking for some organisms. shrug
Any Comparative Physiologists in the house ?
- Tamerlane
So, would this mean that Spider-Man, since he was changed by a radioactive spider bite(and in the 60’s theme states he has radioactive blood) be bluish in pigment?
Um, I have a little problem with this last statement. I find it doubtful that organisms “switch over” to hemoglobin at certain points in their evolution. This seems to imply that our (mammalian) system is somehow “more” evolved than annelids, or arachnids, or whatever, when in fact such creatures have had the same four billion years to evolve systems just as efficient and complex as ours. It seems likely that the seperation of oxygen transporters between different branches is due to phylogenetic legacy: i.e., the first ancestor of branch X had oxygen transporter Y, and descendents thereafter had complex systems based around Y. It would be a major leap to suddenly switch oxygen transporters. I’m guessing that if a certain order of insects uses hemocyanin today, it will continue to do so for the next 100 million years; and be perfectly happy and efficient with it. Such a far removed branch would probably not likely have the capability or “desire” to change to hemeglobin.
Is this making any sense? Sorry, I can’t even tell at this point. It’s late and I should be off to bed.
On the other hand, I have never even remotely studied oxygen transport phylogenies, so I may very possibly be talking out of my ass. I’m sure someone will come along soon to let me know if this is the case.
-b
Of course spider blood is colored. Just look at the goop that pours all over Scott Carey at the end of The Incredible Shrinking Man.
What? I shouldn’t get my scientific information from B-movies (even if they’re very good ones)? Does that mean that I can get into the teleporter with my pet fly?
Wish I could give you objective information about the color of spider blood, but I only see it when it’s mixed to a fine paste with various other spider parts.
mumble…die, spiders, die…
You’d prefer mosquitoes and houseflies? Live, spiders, live! Live and weave! Eat!
bryanmcc:
I didn’t mean to imply that and I certainly don’t hold that view . However…
You’d think so, wouldn’t you ? But such doesn’t appear to be the case . Screw those boring mammals - Let’s look at those spiffy Invertebrates.
Among the Gatropods, most Pulmonates and Prosobranchs have the blood pigment Hemocyanin. However one family of fairly derived freshwater snails ( Pulmonata ), the Planorbidae, has Hemoglobin. Among the Opisthobranchs, some have Hemocyanin ( like the sea hares in the genus Aplysia ), some don’t have anything.
Now in the Bivalves, most don’t have any blood pigments. But two fairly primitive Protobranchs have been found with Hemocyanin and the thought is that this is the primitive condition, with most Bivalves secondarily losing their blood pigments. But 21 species, mostly of ark shells ( Order Arcoida, which are Protobranchs ) associated with hydrothermal vents, have Hemoglobin.
Polychaetes are even more interesting. Many small polychaetes have nothing. Most with pigments have Hemoglobin. But a few ( including Serpulid and Sabellid sand worms - If its tube is all calcine, its a Serpulid, nice and fine. If its tube is soft and sandy, its a Sabellid, fine and dandy 
) have Chlorocruorin, which is probably more similar to plasma ( extracellular ) Hemoglobin, than either is to intracellular Hemoglobin ( other than in color ). The freakish genus Serpula has both pigments . And a few polychaetes have Hemerythrin, which although iron-based, is structurally closer to Hemocyanin.
At least one researcher ( cite on request ) believes that intracellular Hemoglobin is actually the primitive condition and has been retained in various animal groups including some polychaetes. Whereas the more specialized extracellular condition is related to, at least in polychaetes, the lack of capillary beds.
Now many arthropods have Hemocyanin. But the structure indicates that it evolved separately from mollusk Hemocyanin. Crabs and lobsters have Hemocyanin. Daphnia shrimp have Hemoglobin.
Finally, to quote from my old Physiology text( emphasis mine ):
"The establishment of a complete circulation system is a complex change that requires not only relatively minor biochemical changes in porphyrin, but also complex morphological and physiological alterations of the entire organism…In contrast, an initial occurence of Hemoglobin in any tissue immediately endows that organism with the advantage of facilitated diffusion…
It follows from this hypothetical sequnce of events that the scattered occurrence of Hemoglobin is attributable to the universal presence of iron-porphyrin compounds…and that adding Hemoglobin to a pre-existing convective system then becomes a logical step later in evolutionary history."
CalMeachum: Well assuming you have a working transporter - I wouldn’t try it .
Max Torque: Murderer .
Chronos: Good man .
- Tamerlane
I knew I’d get nailed for talking outta my ass…
I was working under the impression that “hemoglobin” specifically referred to the protein family (common in all vertebrates through common descent) that in humans is composed of (among others) two alpha and two beta subunits bound to an iron-containing heme molecule. Would I be safe in assuming that what is called hemoglobin in other lineages are “hemoglobins” only in the fact that they are “heme containing proteins,” and that the protein parts bear no resemblance to vertebral hemoglobin in shape or amino acid composition? Hope so, otherwise I’m in for a serious evolutionary quandry.
I.e., hopefully vertebrates, molusks, and polychaetes have oxygen-transporting molecules, the protein parts of which are un- (or distantly) related, but which are all nominally “hemoglobins” in that they all use the accessory molecule heme. Please tell me this is the case so I can sleep at night…
Sounds like a fascinating system. I’ve been looking for a graduate project in phylogeny; perhaps I’ve found it: generating evolutionary relationships based on these proteins would be quite interesting.
Thanks for the details, Tamerlane!
-b
bryanmcc:
Pretty much . Of course Hemerythrin and Chlorocluorin contain Iron-based heme units as well, so that’s not all there is to it, but you’re pretty close.
Fish, Birds, and Mammals ( and, I’m assuming, Herps ) have an intracellular ( plesiomorphic in the Animalia? ) Hemoglobin with a molecular weight ~68,000. Cyclostomes do not - Their’s are in the 19,100-23,100 range ( stupid Hagfish ). The intracellular Hemoglobin in the polychaete genus Notomastus is ~36,000 and in the ark shell Arca it’s ~33,600.
Extracellular Hemoglobins are almost all HUGE. Whereas mammal intracellular has 4 heme units, each attached to a weight of ~15,000, the extracellular Hemoglobin in the polychaete Arenicola has 96 heme units and a total molecular weight of 3,000,000! Chlorocruorin units are similarly gigantic. An exception is the fly genus Chironomus which has an extracellular Hemoglobin of ~31,400.
And Hemocyanin’s range from around 300,000 to an awe-inspiring 9,000,000 ( I’m awed, anyway ). I have the gastropod Helix down at ~6,680,000.
So rest well .
Sounds like a good idea to me . Have a detailed outline on my desk by next Thursday .
- Tamerlane
I don’t want y’all to have the wrong idea about me: one, I do believe that spiders are the most fascinating creatures in nature. But two, I usually can’t bring myself to get close enough to 'em to squash 'em. Certified arachnophobe.