Sponge is the only multicellular animal without a nervous system. There are no nerve cells or sensory cells. However, touching or applying pressure to the outside of the sponge causes the body to contract locally. Hydra has a nervous system that is characterized by a neural network.
Does the sponge have a nervous system?
The sponge has no nervous system, but somehow it can sense external stimuli and organize coherent behavior. Demosponge, the largest group of sponges, "sneezes" in response to mechanical stimuli. This reaction allows us to remove unwanted substances from our bodies, like our own sneezes.
What is a sponge instead of an organ?
The sponge is considered the oldest animal phyla. They are multicellular, but have no tissues or organs. .. The small pores are the entrance to a complex channel system where the sponge pumps a stream of water from which cells extract small particles of food.
What is the only animal without a nervous system?
The only multicellular animals that have no nervous system are sponges and fine, massive organisms called the Placozoa and the phylum Placozoa. The nervous system of comb animals (comb jellies) and cnidarians (sea anemones, hydra, corals, jellyfish, etc.) is composed of a diffuse neural network.
Does the sponge have an organ system?
Sponges are rare animals in that they lack clear organs to perform various functions. The most important structure is a canal and chamber system called the water flow system, where water circulates and carries food and oxygen to the sponge.
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