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#1
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evolutionary purpose of husks on walnut
After dehusking over a thousand black-walnuts, the question is likely
to surface. Why does a black-walnut or any walnut species have a husk around the nut? Hazelnuts have a leafy type of structure over the nut. Peaches and apricots and plums have fleshy outer covering of their nut which has caught the attention of animals to eat that flesh and spread the seed nut, but not so in the case of walnut husks. So has anyone traced a Evolutionary Purpose for the species of nut bearing trees as to the purpose of the husk? Is it that the husk or some fleshy part is required in the growth of the final nut or hard portion of the nut? Is it that the energy of growth of the nut or hardshell is due to the growth of the husk, so that the husk is integral in the formation of the hardshell and nut inside? I think that is probably the answer, since the seed nut is isolated and nonconnected to the tree except for the husk. So, what is the answer? What is the purpose and function of the husk? Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
#2
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evolutionary purpose of husks on walnut
For example, examine the avocado. This fruit evolved symbiotically
with the now-extinct giant sloth. The animal ate the fruit whole and the fruit offered up its flesh in exchange for having its very heavy seed propagated. This means that human animals now serve the purpose of the three toed sloth. So imagine the walnut being eaten by a now-extinct animal (like giraffe) which digested the husk as low-grade food and excreted a viable seed. This theory incidentally explains why domesticated plants need to be nurseried past the sprouting stage. Seeds excreted into a steaming pile of nitrogen mulch have a much better chance of growing It may also explain why walnut shells (and pecan) are loaded with tannic acid, to acclimatize the seed to an acidic stomach. Compare that to the fig fruit, which is alkaline and has no hard shell. -- Gnarlie http://Gnarlodious.com/Concept |
#3
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evolutionary purpose of husks on walnut
It would seem my previous post was on the right track. The husks were
eaten by large herbivores that are now extinct. From this page: http://www.redorbit.com/news/science/261045/ice_age_survivors/ Two unusual survivors aren't animals at all but plants, one of which is so common that you may have eaten one in the past week or so. The avocado (Persea Americana) is a South American fruit that has survived until modem times thanks to the intervention of humans and fanning. The seed inside the avocado fruit is gigantic and needs to be swallowed and excreted for it to germinate in the wild. However, no modern herbivore in South America can swallow such a seed without choking to death. This may be the case today, but 10,000 years ago South America had some of the largest mammalian herbivores ever, including the enormous ground sloth (Megatherium americanutn), which could grow as tall as two stories. Coprolites (fossilised poo) reveal that these sloths ate everything in their region, including the humble avocado. Here is a classic case of parallel evolution, where two organisms evolved alongside each other in a symbiotic relationship. The loss of one almost caused the extinction of the other. Likewise the osage orange tree (Madum pomtfera), which is found on the North American plains, also yields gigantic fruits that were once eaten (and similarly distributed) by the American sloth and mammoth - some of the only herbivores at the time that could manage the tough- skinned fruit Luckily both the avocado and the osage live for a long time, and both managed to survive just long enough for humans to unwittingly save them. In the case of the avocado it was farmers cultivating them for their fruit, while the osage was saved by the reintroduction of the horse by the conquistadors. |
#4
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function of husk on black walnut evolutionary purpose of husks onwalnut
Gnarlodious wrote: For example, examine the avocado. This fruit evolved symbiotically with the now-extinct giant sloth. The animal ate the fruit whole and the fruit offered up its flesh in exchange for having its very heavy seed propagated. This means that human animals now serve the purpose of the three toed sloth. So imagine the walnut being eaten by a now-extinct animal (like giraffe) which digested the husk as low-grade food and excreted a viable seed. This theory incidentally explains why domesticated plants need to be nurseried past the sprouting stage. Seeds excreted into a steaming pile of nitrogen mulch have a much better chance of growing It may also explain why walnut shells (and pecan) are loaded with tannic acid, to acclimatize the seed to an acidic stomach. Compare that to the fig fruit, which is alkaline and has no hard shell. -- Gnarlie http://Gnarlodious.com/Concept Yes, thanks for the suggestion of avocado and of osage orange in your other post. Before I agree with you on that train of thought, I need to be assured that the husk is not the "growing part" of the seed of the black-walnut. I need assurance that the husk is incidental and not integral to the actual seed growth. If it is incidental, then the sloth or giraffe would benefit from its food and the seed benefit in spreading. But if it is integral to the actual growth of the seed inside, then the evolutionary pattern requires much more insight. Compare the husk of hazelnut to that of black-walnut or the husk of coconut or brazil nut. So I am beginning to think that a husk, no matter what the size of the husk is somehow related to the growth of the seed inside and thus has a function far beyond a animal attractant to spread the seed. Maybe the husk is the pipeline or channel for which the plant nurtures the growing nut-seed inside. If I can rule that out, then I would agree the husk is just incidental and whose function maybe 100% animal spreading. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
#5
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function of husk on black walnut evolutionary purpose ofhusks on walnut
I don't believe the husks were necessary as actual nourishment, and I
would say you are turning one component into a big deal. The actual seed is well protected by multiple layers. Those layers over millions of years of evolution could have served many purposes, like the hooks on cockleburs that both served as a propagation vector and prevented eating. This is similar to the omnivore principle, where overspecialization eventually led to extinction. The thick-skinned gymnosperms had many survival strategies, and hanging on to archaic traits is a valuable asset in adverse conditions. For example, the previously mentioned page states that osage orange somehow survived the extinction of woolly mammoths until the horse was imported from Europe, some 6,000 years without any transport mechanism. Obviously the plant was able to grow, but probably not with the genetic distribution needed for homogenity. This may explain why subspecies arise. Plants typically devote a good part of their metabolic product to scattering their seeds effectively, and there is apparently a good reason for it. -- Gnarlie |
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