This rejection can be stopped by using an immunosuppressant

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canadian goose jacket Why sponges are animalsAristotle thought they were plants; for centuries, we have used canada goose outlet london uk them to scrub ourselves clean, while millions of kids round the planet think they wear square pants and play with stupid starfish. Nevertheless, sponges are in fact the canada goose outlet location oldest living animals, one canada goose outlet ottawa of the most amazing success stories on the planet.Argument rages over exactly how old the earliest sponge is. Some fossils that are claimed to be sponges have been dated back to around 710 MY ago, but not everyone accepts these. Everyone agrees, however, that they were around shortly before the Cambrian Explosion, around 560MY.They now cover every part of the ocean, and can account for up to 75% of the biomass on the floor of the Antarctic ocean. buy canada goose uk 15,000 species have been identified, most of them marine, but there are around canada goose outlet black friday 150 freshwater species. canada goose outlet florida the body forms don form distinct evolutionary lineages).One group of sponges the Archaeocyaths flowered briefly (metaphorically speaking) during the Cambrian, but disappeared after around 15 MY. Most sponges are filter feeders, but a few canada goose outlet uk fake deep sea sponges are carnivorous, spiking tiny crustaceans on their spicules and then absorbing their body contents.Sponges have no neurons, no muscles, no cell cell junctions, no gut, no front/back, no reproductive organs.Studies of canada goose outlet near me DNA show that all the animals form what is called a monophyletic group. In other words, all us canada goose outlet ontario animals share a common ancestor which is canada goose outlet trillium parka black not shared by any other life form. Animals evolved only once, and the earliest branch is the sponges, canada goose outlet in montreal says the data.But strictly speaking, that doesn make them an animal. They could be some multicellular non animal, which branched off before the rest of us started on our animally way.However, recent studies have revealed some amazing canada goose uk things about sponges that clearly place them with the animals they share fundamental characters with us that no other life form shares. We can see in the sponge the beginnings of our own way of organizing our bodies and behaving.They have a simple immune system a sponge will accept a graft of its canada goose outlet las vegas own flesh, but will reject that of another sponge. This rejection can be stopped by using an immunosuppressant widely used in medicine. In other words, we share a biochemical pathway that the body uses to distinguish self and non self.They show coordinated movement Ephydatia muelleri, a small sponge, (rather slowly!) when it is agitated or has inedible ink poured over it. This movement can be induced by pouring known animal neurotransmitters over the sponge, showing the sponge cells are sensitive to stuff that we use canada goose outlet toronto location to activate our neurons.They may not have neurons, but they have the tiny ion channels that are required to make a neuron work. canada goose outlet price Express these genes in another organism, and they work.They have a simple form of the genes required to make canada goose factory outlet vancouver neurons. Express these genes in a toad or fly and they start to make neurons there.This is exactly what we would expect would have happened at the earliest stages canada goose outlet online store of animal multicellularity. Animals didn suddenly appear as running, flying, swimming things. Our earliest, multicellular ancestors would have been perfectly adapted to their environment, but would also have used simple forms of cell cell communication to build canada goose outlet paypal their bodies, and to respond to that environment.Over the vast depths of evolutionary time, those methods were honed and shaped by natural selection, eventually leading to the stupendous array of animal life that the planet has carried, including me, typing these words to you.But that doesn make sponges or in any way lesser beings. They have been on our planet for longer than any other animal around 10,000 times longer than our species. They have survived repeated canada goose outlet los angeles mass extinction events, and that suggests they will probably be around for at least another 600 MY. Not bad for an animal that Aristotle took for a plant.[Added later: Current Biology has this Guide to sponges [should be free], while the excellent Tree of Life website has this page on sponges.]Plants don have the kind of immune system we do (think of all those grafted fruit trees you can carry out grafts between genera!), they don have ion channels (tho they do have signal transduction), and although some species do show coordinated movement (sensitive plant, venus flytrap), most in response to light is in fact differential growth (the plant cells grow more on the dark side of the shoot, because of the inhibitory effect of light on plant hormones).However, even if all canada goose outlet london these characters were also seen in plants, the question would then canada goose outlet niagara falls be what mechanisms are involved. What striking canada goose outlet in new york in the case of sponges is that we share the neurogenic genes, the neurotransmitters and the immune system, whereas plants have very different ways of doing (some of) these things.If we categorized sponges as something non animal, and non plant, they would get lumped in with all the other problematic wierdness filling out the many branches of the eukaryotic canada goose outlet real parts of the tree of life.Sponges are similar enough to animals that they more similar to [rest of animals] than they are to any other group. So removing them from Animalia would lead to more exceptions in descriptions of Animalia than it would solve.As one example, sponges have collagen, just canada goose outlet official like all other animals. So dropping sponges from Animalia would change the definition of Animalia from including eukaryotes with collagen to eukaryotes with collagen, except Porifera That Porifera would have to get stuck into lots of parts of the description of the group of this is rather semantic, of course sponges are going to keep on being sponges canada goose outlet germany regardless of how we think about them.I can see head or tail in the question if sponges (or their larvae) canada goose outlet vip have a body plan with symmetry axes, but I guess not. (Adults their shapes and larvae are according to Wikipedia.)Then I find it interesting that closer to animals with symmetry axes like bilaterians we have placozoans which I gather don have a symmetry axes either, but what I would describe as a broken symmetry: is possible to distinguish a back or dorsal side from a belly or ventral side in Trichoplax adhaerens [Wikipedia] not sure that has any deeper meaning at all, but I find the symmetry axes broken symmetry along an axes true symmetry axes path intriguing. Conceivably broken symmetry could easily evolve into later axes canadian goose jacket.