A starfish can grow a new arm, but you or I cannot? A salamander can regenerate a severed leg, but humans have to use manufactured prosthetic legs? The planarians (flat worms) can be cut into 50 pieces and you will end up with 50 smaller worms. If an arm of a starfish is cut off, you will have two starfish after regeneration and crickets can regenerate their legs.
These are just a few examples of creatures capable of regenerating complex structures of limbs and being able to do this repeatedly! So why do we humans not have this ability? Better phrased, what do they have that allows them to do this that we apparently do not?
I would like to get the biological / anatomical answer if you know it please. Thanks!
2007-07-23 08:46:21 · 9 answers · asked by Answer-Me-This 5 in Science & Mathematics ➔ Biology
Actually, you DO have the ability to regenerate. Just not everywhere.
One good example is bone marrow. If a person loses all the bone marrow in their body (sometimes we do this to them on purpose), a little bit of bone marrow can grow and no only replace their lost bone marrow but change all their blood cells and the like (since that's where blood cells come from in the first place).
Another is the liver. It is possible to donate your liver more than once. This is because they only take half your liver and put it in a recipient... and each of you ends up growing a full liver from just the part.
But no. You can't grow back an arm. The difference in all this has to do with stem cells and cell destiny.
As you have probably heard from the news, when we start out we are pretty much entirely stem cells. Cells which can divide and become other things. But even by the time we're born the balance has gone the other way... most of the cells in our body have lost that ability. Sections of the DNA are blocked off pretty much permanently, even in most of the stem cells you have left. So even though a few liver cells can produce a whole new liver, no amount of liver cells can produce a kidney.
The reason our cells turn off huge sections of their DNA is just because we have so blasted much of it. The cells in our bodies are VERY specialized and often completely dissimilar from one another, even though they start out the same. It may not be a big deal of some starfish cells start acting weird, but if some of your brain cells go rogue and produce stomach acid then you've got a BIG problem on your hands (or in your head).
So the short version is that we have to give up some of our ability to regenerate to be complex. Like your computer... if one part breaks you can't just grab a chip from somewhere else in your computer, hammer it a bit, and squish it in. That would only make things WORSE. A starfish is more like an abacus. If you lose one of the beads, you can just move a bead over from somewhere else. No big deal because they weren't too different to begin with.
Hope that helps!
2007-07-23 13:23:05 · answer #1 · answered by Doctor Why 7 · 2⤊ 0⤋
This is both genetic, and structural. Humans chose a different healing path. Instead of having a long drawn out wound and extended recuperation (but a new hand for example), mammal's choose to scar and rapidly close the wound. This reduces vulnerable recovery time through fast crude healing. The general idea is to seal the would as fast as possible and get on with life (if the creature can live with the lost of whatever was cut off). Most of the creatures that regenerate do not live the fast paced life of a mammal. Many are cold blooded, and can take a month time out to heal well. Most mammals would starve.
There is some interesting research that shows that even mammals can do a bit of limb regeneration if they don't develop scar tissue. So it is not likely that you will ever naturally grow a new arm, but there are mice that can grow new toes. Maybe treatments can be made someday.
2007-07-23 09:14:42 · answer #2 · answered by dna man 2 · 1⤊ 0⤋
You are so much more complex than a starfish. They don't even have spinal cords. I am pretty sure crickets can't grow back legs. As you climb the ladder of animal complexity, once you get to the cordates, the ability to repair gets so much more complicated.
A starfish has some tubules, internal muscles, and a weird, part-skin, part-exoskeleton type skin. It isn't that hard to grow more. You however have skin (3 layers), many bones and muscles, nerves, blood vessels, lymphatic tissues and all sorts of connective tissue holding it all together. To reproduce all that in exactly the same way and then make sure it is properly connected to the circulatory, lymphatic and nervous systems so that is can work right is far beyond our scientific reach. Your arm has to be grown right the first time (naturally) in order to function properly. And that depends upon proper genetic signaling, good maternal nutrition, and a whole host of other influences which I am sure I don't even know about.
I hope this helps you understand!
2007-07-23 10:37:39 · answer #3 · answered by Ellie S 4 · 0⤊ 1⤋
Most do it for survival, however some species can regenerate into multiple starfish as a form of asexual reproduction. Regardless, mutilating them is pretty cruel.
2016-04-01 09:16:32 · answer #4 · answered by Anonymous · 0⤊ 0⤋
they have the power of regeneration n we dont have regeneration power in all part of our body except some like skin
2007-07-23 08:51:19 · answer #5 · answered by amrita 3 · 0⤊ 3⤋
I dont know the answer buy I have a younger cousin and I hear he grew a foot.
2007-07-23 11:52:54 · answer #6 · answered by mr.answerman 6 · 0⤊ 3⤋
LOL..thats a very good question. But it's a mystery why things are made the way they are..
2007-07-23 08:49:31 · answer #7 · answered by ? 6 · 1⤊ 3⤋
i have no ideas of this..well, all i can say.. you are not patrick (starfish).. lol
2007-07-23 13:50:00 · answer #8 · answered by NEILISA **Shane's Mama** 6 · 0⤊ 1⤋
hmmm....we have bones and they dont
2007-07-23 08:49:55 · answer #9 · answered by naenae73 2 · 0⤊ 3⤋