Best answer: What animal does not have a nervous system?

The only multicellular animals that have no nervous system at all are sponges and microscopic bloblike organisms called placozoans and mesozoans.

What has no nervous system?

Nervous systems are found in most multicellular animals, but vary greatly in complexity. The only multicellular animals that have no nervous system at all are sponges, placozoans, and mesozoans, which have very simple body plans.

Which animal does not feel pain?

Though it has been argued that most invertebrates do not feel pain, there is some evidence that invertebrates, especially the decapod crustaceans (e.g. crabs and lobsters) and cephalopods (e.g. octopuses), exhibit behavioural and physiological reactions indicating they may have the capacity for this experience.

Do starfish have nervous systems?

Asteroidea, starfish, constitutes a major part of the macrobenthos in most marine environments. Being members of the echinoderms, they have a nervous system with no well-defined central nervous system.

Do jellyfish have nervous systems?

Do they have brains? No, jellyfish have no single centralized brain. Instead, they have radially distributed nervous systems that are adapted to their unique body plan. … In fact, most jellyfish species show some degree of neuronal condensation that serves as an integrative nervous system.

THIS IS INTERESTING:  What all does emotional literacy influence?

How did animals differ in nervous system?

Compared to invertebrates, vertebrate nervous systems are more complex, centralized, and specialized. While there is great diversity among different vertebrate nervous systems, they all share a basic structure: a CNS that contains a brain and spinal cord and a PNS made up of peripheral sensory and motor nerves.

What is the nervous system in an earthworm?

The nervous system of an earthworm is composed of a primitive brain of fused ganglia, a ventral nerve cord, and peripheral nerves. Impulses from the earthworm’s sensory cells are transmitted by the peripheral nerves to certain parts of the body and proper responsive movements are coordinated.

What animals dont drink water?

How some animals survive on almost no water

  • Tortoise. In the Mojave and Sonoran deserts, several tortoise species survive off their urine. …
  • Kangaroo Rat. The kangaroo rat never has to drink water—it just gets it from the seeds it eats. …
  • Thorny Devil. …
  • Water-Holding Frog. …
  • Camel. …
  • Sand Gazelle.

What animals dont exist?

7 Animals That No Longer Exist Because Of Humans

  • The Dodo.
  • The Black Rhino.
  • The last Quagga.
  • The Zanzibar Leopard.
  • The Passenger Pigeon.
  • East Coast Puma/Cougar.

Is jellyfish an animal?

But despite their name, jellyfish aren’t actually fish—they’re invertebrates, or animals with no backbones. Jellyfish have tiny stinging cells in their tentacles to stun or paralyze their prey before they eat them.

What is the nervous system of a spider?

The nervous system of spiders, unlike that of other arachnids, is completely concentrated in the cephalothorax. The masses of nervous tissue (ganglia) are fused with a ganglion found under the esophagus and below and behind the brain.

THIS IS INTERESTING:  You asked: What is the enteric nervous system involved in?

What is nervous system of cockroach?

The nervous system of cockroach consists of a series of fused, segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side. Three ganglia lie in the thorax, and six in the abdomen. The nervous system of the cockroach is spread throughout the body.

Do crayfish have central nervous system?

The central nervous system of crayfish consists of a chain of segmental ganglia that are linked by cables of intersegmental axons. Each ganglion contains a highly-ordered core of longitudinal tracts, vertical tracts, commissures, and synaptic neuropils.

Do snails have a central nervous system?

The most highly centralized nervous systems include brains. Gastropods and snails do not have brains, but their nervous systems are centralized to a certain extent, and they have analogous structures, which are several pairs of ganglia (clusters of neurons) connected by a nerve cord.

Are jelly fish alive?

Jellyfish are prehistoric creatures that have inhabited oceans around the world for millions of years. Although their gelatinous bodies and graceful movements make them appear to be complex creatures, they are actually quite simple in both form and function. Jellyfish are planktons that have no bones, brain, or heart.

Do annelids have a nervous system?

A Segmented Ventral Nerve Cord Typifies Annelids and Arthropods. … Nervous system organization in the rostral end of an annelid worm. A ventral nerve cord with more or less distinct ganglia connects with a fused pair of cerebral ganglia (brain) dorsal to the pharynx (part of the digestive tract).