2006-12-06 13:48:01 · 5 answers · asked by Dellajoy 6 in Science & Mathematics ➔ Zoology
That depends on your definition of pain!? For example, Cnidarians (Jelly Fish and Corals) have what would be considered the simplest 'nervous system' made up of a diffuse neural net but do they feel pain as we do......probably not.
More physiologically complex organisms, for example, invertebrate cockroaches possess neural ganglion (provide nervous control of segments)that are nearly as complex as its brain. Cockroaches can be dissected in a lab and still live for an extended period. Its therefore unlikely that they feel pain as humans do ie., we would go into shock and die from the pain alone.
Other vertebrates possess a similarly complex neural system to humans....fish being the most 'primitive' vertebrates are therefore likely to be the 'simplest' organisms that feel such pain!?
2006-12-06 20:11:09 · answer #1 · answered by gnypetoscincus 3 · 2⤊ 0⤋
that would be a tough call, and is dependent on your definition of pain. If you define pain as a feeling of discomfort, emotional distress or unpleasant physical sensation; even plants feel pain. Trees have been found to release chemical to warn other trees when attacked by pests. This can be compared to humans crying out in pain to warn other humans. I have even microscopic animals engage in death throes that could be associated as pain, when the water on the slide I am viewing them is getting to hot foe them or evaporating. Lastly until just recently it was thought that fish did not feel pain because the lacke the neccessary nerves. this has been found to be untrue
2006-12-06 14:40:21 · answer #2 · answered by geo3598 4 · 1⤊ 0⤋
While it seems like a simple question, the answer may depend more on how you define pain than the "simplicity" of the animal.
If you pick up an earthworm, does it not seek to move away? So what motivates it?
Could pain simply be any unpleasant stimulous? Even very simple organisms move away from unpleasant stimuli.
2006-12-06 14:38:36 · answer #3 · answered by Ron E 5 · 1⤊ 0⤋
The single cell protozoa are the simplest animals on the planet.
While they may not experience pain as we know it, they will attempt to flee from the ***** of a needle, or any other adverse stimulation.
2006-12-06 17:29:09 · answer #4 · answered by dropkick 5 · 2⤊ 0⤋
Maybe a reptile such as a turtle or crocodile; or an amphibian like a frog or toad. Possibly a squid, octopus, or cuttlefish too.
2006-12-06 15:40:57 · answer #5 · answered by Professor Armitage 7 · 0⤊ 0⤋