2007-02-26 10:37:20 · 11 answers · asked by ari 2 in Science & Mathematics ➔ Zoology
First of all, not all "hearts" and "brains" are created equal. Let's define a heart as any muscular structure that propels blood or hemplymph through an animal. And let's call a brain any complex of neural ganglia. Don't worry if that doesn't make sense; we just had to get it out of the way for the sticklers out there.
Vertebrates (which include all fish, amphibians, reptiles, birds, and mammals like us) have both a heart and brain. Arthropods (which include insects, spiders, crustaceans, and some other things) have both as well. All mollusks (clams, snails, squid and octopi) have hearts, but only the mollusks known as cephalopods (squid and octopi) have brains, too. Annelids (segmented worms, like earthworms) have hearts, but not brains.
None of the other major animal groups, such as echinoderms (sea stars, sea urchins), cnidarians (jellies, corals, anemones), sponges, flatworms, or roundworms, have either.
2007-02-26 11:09:43 · answer #1 · answered by Ben H 4 · 1⤊ 0⤋
This Site Might Help You.
RE:
do all animals have a heart and a Brian with an exception of jellyfish?
2015-08-12 21:23:31 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Do All Animals Have Brains
2016-11-11 05:17:27 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Brian may take exception to this
2007-02-26 10:40:46 · answer #4 · answered by Anonymous · 0⤊ 1⤋
I don't have a Brian, but I do have a john..I know someone with a Peter...Let's be Frank- learn to spell.
2007-02-26 10:42:57 · answer #5 · answered by dragonwythe 3 · 0⤊ 1⤋
Worms just have nerves and a circulatory system, not as centralized as the heart and brain that you are thinking of.
2007-02-26 10:40:50 · answer #6 · answered by rscanner 6 · 0⤊ 0⤋
i have a cousin Brian
2007-02-26 10:40:45 · answer #7 · answered by MYCHEMICALROMANCE!! 1 · 0⤊ 0⤋
Snails don't have a brain per say, they have a cerebral ganglion.
2007-02-26 10:41:11 · answer #8 · answered by Anonymous · 0⤊ 1⤋
i would say that in general, any animal with radial symmetry lacks a "Brian"
2007-02-26 16:11:49 · answer #9 · answered by dane hoy 2 · 0⤊ 1⤋
no...small organisms do not but not sure if there are any unicellular organisms that are classified with the animal kingdom
my answer would be no
2007-02-26 10:40:56 · answer #10 · answered by Seanoso88 1 · 0⤊ 1⤋