Which of the following animals have nervous system but no brain?
Step by step answer:Hydra has anatomically one of the simplest nervous systems which is a nerve net formed by the nerve cells present in the epidermis of the Hydra with no sign of a brain.
What has a nerve net with no brain?
The nervous system of the starfish is very simple… there is no brain and there are not even any ganglia to coordinate movement. The nervous system is characterized by a nerve ring that surrounds the mouth.
Which of the following animals first showed nervous system?
Simple nerve nets seen in animals like Cnidaria (jellyfish) evolved first, consisted of polymodal neurons which serve a dual purpose in motor and sensory functions. Cnidarians can be compared to Ctenophores (comb jellyfish), which although are both jellyfish, have very different nervous systems.
In which of the following animal is the neural system is well organized?
The neural system is better organised in insects, where a brain is present along with a number of ganglia and neural tissues. The vertebrates have a more developed neural system.
Does amoeba have nervous system?
Amoeba is a unicellular organism which means it is made up of only one cell. It does not have a central nervous system or brain.
Do Cnidaria have a nervous system?
Cnidarians have simple nervous systems and it was probably within this group or a closely-related ancestor that nervous systems first evolved. … We propose that these multifunctional neurons resemble the ancestors of the more specialized neurons that we find in higher animals today.