Term
| Chordate general characteristics: |
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Definition
| Triploblastic, eucoelomate, bilaterally symmetrical deuterostomes |
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Term
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Definition
| all types of habitats: marine, freshwater, and terrestrial. |
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Term
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Definition
| A notochord (“back-cord”): the chordate notochord is a flexible rod running posteriorly from the head to the tail. The notochord provides an attachment site for muscles and a support structure that can bend. The notochord consists of large fluid-filled cells encased in a stiff ‘cartilaginous-like’ connective tissue. The notochord persists in some primitive chordates, but it is replaced for the most part by bone in the vertebrates (in vertebrates, the intervertebral disks are remnants of the notochord). |
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Term
| In primitive chordates, they are slits that open to the outside. |
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Definition
| Pharyngeal gill slits. The region posterior of the mouth is the pharynx (“gullet”); in the primitive chordates, there are slits that open to the outside. These slits allow water to leave the digestive tract before entering the stomach and intestines. In the invertebrate chordates, the pharynx and associated structures functions in filter feeding (gills that are located off of the pharynx filter out material in the water column that passes through the mouth). We will see that a number of structures associated in the pharyngeal region of primitive vertebrates are adapted for other purposes in the higher vertebrates, such as the Eustachian tubes and middle ear bones. |
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Term
| A dorsal, hollow, single nerve cord. |
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Definition
| The nerve cord is a single nerve cord, as opposed to the paired ventral nerve cord of the invertebrates. This nerve cord develops the brain and spinal cord of the central nervous system. |
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Term
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Definition
| a tail of variable length that extends past the anus. The tail contains skeletal structures and muscles, and it provides a major means of propulsion for some chordates. |
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