Why was a jellyfish considered to be called a living organism if it doesn't have a brain or a heart?
how can it live if it has no heart?
how does it move if there were no command center (brain)
how can it live if it has no heart?
how does it move if there were no command center (brain)
pzifisssh
Favorite Answer
Things that we call "living" are things that consume energy in some form or another (e.g., food or sunlight), and they all make little copies of themselves that grow up to be (mostly) like their parents.
http://en.wikipedia.org/wiki/Life
Jellyfish do all of those things. So do trees and grass and mushrooms and mildew. They have (somewhat) different ways of doing it, but we call them all "alive."
Jellyfish don't have brains but they do have nerves and hormones that coordinate the movement and function of different parts of the animal's body.
http://en.wikipedia.org/wiki/Jellyfish
Some simpler/smaller animals than that use hormones alone.
Anonymous
It doesn't need a heart because it's so thin and porous. Oxygen can diffuse directly from the water around it to all through it's body with no pump to help it along.
Jellyfish don't have brains but they do have nervous systems. It's like a (very simple) distributed brain running throughout it's body that executes a few basic responses to external stimuli. If the nerves in the tentacles sense something touching them they trigger other nerves that move the arms to pull it up to the stomach... you get the idea. I do believe some species have ganglia, which are clusters of neurons that act like little tiny brains spread out throughout it's tissue.
Of course, a tree is alive, right? So are bacteria and fungi. Having a brain is optional. Remember that! Politics will make much more sense to you if you do.
The Big J
take it down a notch and think about bacteria... it is a single cell organism. organisms are living organisms so... throw a few thousand, or million or more together and you can get a jelly fish, which may not have a brain, or a heart, but is still a living organism.
bkeli5234
there are plenty of other living organisms that lack these things as well... if you simply look up the definition to "living organism" i think you will find the answer quite easily (ex. how is a tree considered a living organism? it barely moves...)