Your question: Which of the following has nervous system but no brain?

The animal that has a nervous system but no brains belong to the phylum Coelenterata class Hydrozoa. It contains the nerve cells and the unpolarised nerve cells of the epidermis in the organism form the nerve net but there is no brain presence in the brain. … Earthworm- it belongs to the phylum Annelida.

Which animal has neurons but no brain?

Scientists have shown that animals as simple as the roundworm C. elegans, with a brain of just 302 neurons, need sleep to survive. Cassiopea has no brain to speak of—just a diffuse “net” of nerve cells distributed across their small, squishy bodies. These jellyfish barely even behave like animals.

Do grasshoppers have a brain?

The central nervous system (CNS) of the grasshopper consists of a brain and a set of segmental ganglia that together make up the ventral nerve cord. Each ventral nerve cord ganglion develops very similarly during early embryogenesis.

Do Invertebrates have a brain?

2. The neural capacity of invertebrates. Except for the cephalopods, invertebrates have small nervous systems, consisting of many small brains (ganglia). Because of the small number of neurons and the distributed organization of their nervous systems, invertebrates are thought to have limited cognitive capacity6.

Do insects feel pain?

Over 15 years ago, researchers found that insects, and fruit flies in particular, feel something akin to acute pain called “nociception.” When they encounter extreme heat, cold or physically harmful stimuli, they react, much in the same way humans react to pain.

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Which invertebrates has the largest brain?

Cephalopods have the largest of all invertebrate nervous systems, with a brain weight-body weight ratio exceeding that of most fish and reptiles.

What are the 3 types of the brain?

The Architecture of the Brain

The brain can be divided into three basic units: the forebrain, the midbrain, and the hindbrain. The hindbrain includes the upper part of the spinal cord, the brain stem, and a wrinkled ball of tissue called the cerebellum (1).

What do invertebrates have instead of a brain?

Simple invertebrates have small nerve cords throughout their body. These animals have no brain or head. On some animals, the groups of nerve cords form together to form something called a ganglion. This is what controls the movements of certain parts of the body.