Arthropoda - The Arthropod is home to the largest amount of species, which makes it the largest Phylum in existance. All living insects which account for about 75% of all living beings on earth. Species of Arthropoda can be found in air, land, and water. The average Arthropoda is made up of appendages. Each appendage is used for a specific purpose. Their nervous systems are highly developed, with chains of ganglia serving various parts of the body, and three fused pairs of cerebral ganglia forming a brain. Ganglia being a structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fiber.
Spiders - Spiders have a brain that is formed by fusion of the ganglia for the head segments ahead of and behind the mouth, so that the esophagus is encircled by this conglomeration of ganglia. Like most Arthropoda the ganglia accounts for much of the nervous system.
Scorpions - Scorpions are invertebrates in the class Arachnida. They have a "head" which includes a brain. They do not have a spinal column or spinal cord. They do have sensory organs which connect to the brain through neurons and nerves and nerve chords.
Crabs - Crabs have a difference in nervous system compared to mammals but just like mammals they can feel pain and even stress. Crabs contain a suitable central nervous system and they contain receptors to feel. They have vision despite lacking a visual cortex which allows humans to see.
Spiders - Spiders have a brain that is formed by fusion of the ganglia for the head segments ahead of and behind the mouth, so that the esophagus is encircled by this conglomeration of ganglia. Like most Arthropoda the ganglia accounts for much of the nervous system.
Scorpions - Scorpions are invertebrates in the class Arachnida. They have a "head" which includes a brain. They do not have a spinal column or spinal cord. They do have sensory organs which connect to the brain through neurons and nerves and nerve chords.
Crabs - Crabs have a difference in nervous system compared to mammals but just like mammals they can feel pain and even stress. Crabs contain a suitable central nervous system and they contain receptors to feel. They have vision despite lacking a visual cortex which allows humans to see.