Of blood, that is. The colors are nice, but also very nice are those gorgeous resonant organic molecules.
(click for larger image)
Lovely molecules make lovely colors
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
So there really are critters with copper-based oxy transport? Cool — who knew that Mr. Spock was a cephalopod? But that’s an interesting distribution of taxa — some arthropods, and some molluscs, but not all? What do we know about the evolutionary origins of blood and circulatory systems?
Okay, so maybe some worms don’t have cool names.
Looking at those diagrams, the green Chlorocruorin seems to be identical to Haemoglobin, but with an extra O in one spot. Does that mean it’s more efficient at transporting oxygen? Because that’d be a great excuse to give cyborgs and stuff green blood!
I’m taking a course on transition metal chemistry at the moment, including the source of pigment colour. It is interesting stuff.
It doesn’t actually have an extra O, Zeppelin; it has an oxygen replacing a CH2 group (so it has an aldehyde functionality instead of an alkene). That doesn’t automatically make it more efficient, as that oxygen isn’t being transported- it’s an integral part of the molecule. The oxygen being transported will be coordinated to the metal centre.
I’d really like to see what colours these molecules turn when you expose them to other ligands, such as carbon monoxide, nitrogen monoxide, cyanide, nitrite, etc….
Penis worms?
Wouldn’t want to get that.
NitricAcid: That makes, sense, thanks! Ah well.
chimera:
If you walk without rhythm, you won’t attract the worm.
So, invertebrate blood must be relatively tough to see because it is very limited in volume or mixes with other fluids or is much more subtle in coloration? One thing about us vertebrates is that we deliver the color; brilliant, vibrant red every time we have an unfortunate encounter with unfriendly vertebrates or other objects out to kill us like unfolded corners of paper.
So, all practical issues aside, if you were a phlebotomist in an invertebrate hospital and somehow were able to extract only blood for medical diagnoses or for a bloodbank to treat other invertebrates in need, would you actually see vivid blue or green or violet? Or would it just be a subtle hue, perhaps nearly invisibly subtle, in a fluid of otherwise relatively unremarkable color?
I like these posts about biology*, I’m a physics teacher who is teaching a general science course with a biology component. I use these in my class.
*SHHH! don’t tell the fizzics teachers’ gang. They’ll kick me out of the group and we have our pizza and applied optical properties of liquids (aka beer tasting) meeting this Friday.
I wondered which vertebrates did not have red blood; apparently the answer is Channichthyidae, or white-blooded fish, or crocodile icefish.
I always figured PZ was a blue-blood.
It’s OK. I like to sneak physics and chemistry into my biology classes. & I smuggle math into neurobiology and make the students cry.
Yeah, we vertebrates have a high pressure, high volume vascular system. Give a tunicate a shaving cut, and they just sort of ooze. We gush.
Science for the win. I knew that there are multiple blood chemistry possibilities, and molluscs in particular have some pretty snazzy evolutionary variations. The echinoderms have yet another solution to respiration that doesn’t require blood at all. I am wondering about plants. Plants respire in a completely different way than animals, and have sap rather than blood. Is this due to shared genetic ancestry, or is plant respiration evolved completely independent of animal respiration?
Plants, like most other eukaryotes, have mitochondria and can do respiration metabolism: disassemble biological molecules and combine the parts with oxygen.
However, plants’ circulatory systems is evolved completely separately from animals’ circulatory systems. That is because they are separate inventions of multicellularity, and it is also evident from the numerous differences of details of the systems.
Thank you for answering my question. I realize that they have evolved separately, but at some point in the evolution of life there is a marine organism that is the ancestor of both plants and animals. Wouldn’t whatever method of respiration it used be the basis of all respiration? Is photosynthesis or chemosynthesis primary for multicellular organisms? Shouldn’t there be a heavily modified gene, or gene sequence for this that would be common to all multicellular life? I am just wondering if we know enough about that ancestor to know how it respired or if it had something like blood.
The statement that hemerythrin is “1/4 as efficient” as hemoglobin piqued my interest, and got me reading. You might think this is simply because hemoglobin is a tetramer and therefore has four times as many binding sites, but this is not the case as hemerythin is actually an octamer! I knew this didn’t make sense, but I couldn’t remember my biochemistry well enough to know where the factor of 4 actually comes from. The answer? It turns out the factor of 4 *is* related to hemoglobin being a tetramer, but in a different way.
The real story is that hemoglobin is a better transporter because it binds oxygen “cooperatively”, such that if one monomer (of the tetramer) binds oxygen the others become more likely to bind too, due to conformational changes caused by binding the oxygen. This way the ‘four oxygen’ and ‘zero oxygen’ states are more favored over intermediate states, which is good for loading/unloading oxygen. Hemerythin does *not* bind cooperatively despite being an octamer, so it does not get an 8x boost in transport efficieny. Hemoglobin has a lot of interesting history actually, and it is the molecule for which the science of cooperativity was first developed back around 1910 by Archibald Hill.
This brings up a nitpick, that hemoglobin would only be “four times as efficient” if it was perfectly cooperative. But in fact, as measured by its Hill Coefficient, it is really only about 2.5 to 3 times as efficient as non-cooperative molecules. So the image should really say hemerythin is “1/3 as efficient”.
I was going to send a link to this to my chemistry students, but then I saw mention of penis worms and decided to bag it. If I try to have a discussion, the loudmouths would talk about nothing else, rendering any hope of a serious discussion impossible.
@ealloc #18: Yup, that is very interesting.
I wonder if this low efficiency represents an evolutionary limit for the size of marine worms.
Still, I wonder if it gives them some specific advantage.
Oh, Mike, please don’t give up so easily. =^_^=
There are four different colours of blood in that picture.
Why not:
Tell the class that you are going to speak about the four different kinds of blood, and will then ask the class to divide into four groups, and that each group will then be asked to pick one animal out of their chosen blood type to investigate – quietly – how it goes about the chemistry of respiration.
The loudmouths get their penis worms, and they and everyone else gets to learn something.
Um, so the lovely colors of things other than blood aren’t due to molecules?
Nope, because the last common ancestor between plants and animals was a single celled organism. The plants evolved from single celled organisms that specialized in being photosynthetic autotrophs, while animals evolved from single celled organisms that specialized in being heterotrophs that fed on the autotrophs. The issue is that, especially when you’re a single celled organism, redundant methods of gaining ATP are pretty costly so the SCOs (single celled organisms) that specialized in doing one or the other had a tremendous advantage against SCOs that tried doing both.
Both photosynthesis and aerobic respiration were invented loooong ago by bacteria. SIngle- and multi-cellular eukaryotes alike can only do them because of the endosymbiotic origin of mitochondria and chloroplasts that are direct descendants of such bacteria. So oxygen-using metabolism only evolved once, back before there were nucleated cells at all. Oxygen transport, which is what the molecules in the OP accomplish, has evolved multiple times in multicellular animals.
Is the common ancestor fungi? There is an enormous span of time between the first stromatolites and the earliest animal and plants fossils, so how do we know when the split occured? A lot of the single celled organisms that were considered plants back when I took biology 101 are now classified as protists. I find it very confusing to have a group that lumps algae and amoebas,
IIRC, Annie Dillard’s Pilgrim at Tinker Creek goes into some detail about the mechanisms of chlorophyll, including the claim that hemoglobin has the same molecular structure except for an iron atom in its core where chlorophyll has copper.
Any truth to that one?
Chlorphyll has a magnesium atom coordinated by the porphyrin ring system.
It isn’t exactly the same molecular structure, but chlorophyll and heme are produced by the same metabolic reactions. The core of chlorophyll is magnesium according to wiki.
Annd, Nerd is much faster than me. :)
Well, ‘protists’ has always been a trashcan category; it just means ‘all eukaryotes that aren’t fungi, plants, or animals’. Molecular phylogeny is slowly sorting out the evolutionary relationships among the eukaryotes. Fungi are much closer to animals than either is to plants, which are really just a specialized branch of green algae.
Little can be surmised about the last common ancestor of [plants + green (& red) algae] and [animals + fungi], other than it was a unicellular eukaryote (with nucleus), had flagella, and had mitochondria but no chloroplasts.
Neat, this reminds me that I was going to look into this topic. My girlfriend is a med student and something got us talking about blood production and bone marrow, I was looking at her notes. I knew that red blood cells, platelets and other things were produced in the bone marrow, but looking at the notes I realized I really have no knowledge at all about the blood of invertebrates. Going to look that up now.
Nerd… @ # 27 & Tethys @ # 28 – Thanks!
I recollected that Dillard claimed that the difference in that one atom caused the differences in color, and carelessly extended that to red=iron oxide, green=copper oxide. That’s my story, to which I shall adhere.
Taken by itself, that parallelism does seem to imply a fairly close connection between animal/plant genetics, though I think Dillard focused on the chemical efficiency/necessity of certain molecules. Had she had the opportunity to read our esteemed host’s post here, no doubt she would have waxed even more eloquent.
(ahem!) … and I carelessly extended … @ # 32
I almost never Award Internets but this from Moggie #8 really deserves one
Actually, Pierce R. Butler, copper oxide is either black (CuO) or red (Cu2O). The green patina you usually see on exposed copper is a basic copper carbonate Cu2(OH)2CO3.
The actual porphyrin unit in hemoglobin and chlorophyll aren’t exactly the same (chlorophyll itself isn’t the same- there’s chlorophyll A and chlorophyll B, at least), but yes, the most important difference is the metal atom.
Chas
Thank you for the reply. I’ve done a bit more reading about the things classified as algae. Chlorarachniophytes are an example of something that is classified as algae, but it also eats smaller protists. It gets the chloroplast by eating algae, so it seems silly to classify it as an algae. It seems that at the level of protists, there are many organisms that don’t fit neatly into either the animal or vegetable category.
Horseshoe crab blood is quite a rich shade of blue. I would assume the same is true for the others.
That’s haemerythrin, barbarians.
The metal atom is not what causes the difference in color. Haem is red because of the porphyrin ring, not because of the iron atom; and magnesium compounds aren’t green anyway.
“Classified”, or “algae”? :-)
Chlorarachnio”phytes”, foraminifera and the that caused the Irish potato famine (a plasmodio”phyte”) are close relatives, with various interspersed.
Thank you for the chart David, that makes a lot more sense. I can’t copy paste from the PDF which doesn’t call it an algae, but the first sentence in the wiki identifies it as a mixotroph algae, and then describes how it gets its chloroplast. I didn’t know if classifying it as an algae was an error as I had never heard of chlorarachniophytes, but logically, how it could be algae if it had to acquire chloroplasts by eating algae? The multinucleate cells are pretty fascinating.
Very cool! I never realized iron had a relatively minor role in the coloration of haemoglobin (when compared to green blood). I always thought it was based on the ion color.
I liked to think that the metallic dragons in D&D used a chromate-dichromate based transport system. Golden blood.
NitricAcid @ # 35 & David Marjanović @ # 38 – thanks for the corrections!
Damn, there goes another (beautifully readable) pop-science writer toppled off her pedestal… (or maybe, more likely even, I misremembered her exact points).
ChasCPeterson
I’ve been reading this study which tries to establish the roots of the various eukaryote lineages. I don’t think it contradicts your statement, but I think it casts doubt on the theory that multicellularity (?) arose independently in plants and animals. AFAICT, it looks like the blueprints for building a body larger than one cell that are found first in putative algae like grypania, would have passed easily between the first species through symbiosis, and because cyanobacteria are capable of horizontal gene transfer. Cyanobacteria were ubiquitous in the environment in which early life differentiated into kingdoms, it appears that they are the direct ancestor of both plants and animals. (assuming I have understood this correctly, it is pretty technical) Here is a part of the studies conclusion:
The study is Analysis of Rare Genomic Changes Does Not Support the Unikont–Bikont Phylogeny and Suggests Cyanobacterial Symbiosis as the Point of Primary Radiation of Eukaryotes http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817406/
Ooooh, conjugated double bonds !!
@38 I don’t believe that the metal does not have an effect on the colour, or the colour wouldn’t change when you coordinated an oxygen or carbon monoxide to the metal. In the case of chlorophyll, I’m sure that the metal doesn’t have much to do with the colour, but I have my doubts about the transition metal complexes.
Now I can’t stop thinking about an experiment I tried as a kid, when I had just learned about the similarities between the chlorophyll molecule and the heme group, and tried to react blood with magnesium metal, hoping it would turn green….