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12.28: Vertebrate Classification

Last updated

Aug 11, 2023
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- 12.27: Vertebrate Reproduction
- 12.29: Vertebrate Evolution

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f-d_6bb4336456265c5ea985dc85100811ee32db1a038e12ae2e9032337f+IMAGE_TINY+IMAGE_TINY.jpg

The stingray. Fish?

Of course. But what type? Of the nine classes of vertebrates, five are fish. Each of the five classes has distinguishing characteristics that allow members to be classified appropriately. Stingray are cartilaginous fish, related to sharks.

Vertebrate Classification

There are about 50,000 vertebrate species, and they are placed in nine different classes. Five of the classes are fish. The other classes are amphibians, reptiles, birds, and mammals. Table below lists some of the distinguishing traits of each class. Classes are listed in order of evolution.

Class	Distinguishing Traits	Example
Hagfish	They have a cranium but no backbone; they do not have jaws; their endoskeleton is made of cartilage; they are ectothermic.	hagfish
Lampreys	They have a partial backbone; they do not have jaws; their endoskeleton is made of cartilage; they are ectothermic.	lamprey
Cartilaginous Fish	They have a complete backbone; they have jaws; their endoskeleton is made of cartilage; they are ectothermic.	shark
Ray-Finned Fish	They have a backbone and jaws; their endoskeleton is made of bones; they have thin, bony fins; they are ectothermic.	perch
Lobe-Finned Fish	They have a backbone and jaws; their endoskeleton is made of bones; they have thick, fleshy fins; they are ectothermic.	coelacanth
Amphibians	They have a bony endoskeleton with a backbone and jaws; they have gills as larvae and lungs as adults; they have four limbs; they are ectothermic	frog
Reptiles	They have a bony endoskeleton with a backbone and jaws; they breathe only with lungs; they have four limbs; their skin is covered with scales; they have amniotic eggs; they are ectothermic.	alligator
Birds	They have a bony endoskeleton with a backbone but no jaws; they breathe only with lungs; they have four limbs, with the two front limbs modified as wings; their skin is covered with feathers; they have amniotic eggs; they are endothermic.	bird
Mammals	They have a bony endoskeleton with a backbone and jaws; they breathe only with lungs; they have four limbs; their skin is covered with hair or fur; they have amniotic eggs; they have mammary (milk-producing) glands; they are endothermic.	bear

Summary

The 50,000 species of living vertebrates are placed in nine classes: hagfish, lampreys, cartilaginous fish, ray-finned fish, lobe-finned fish, amphibians, reptiles, birds, and mammals.

Review

Which was the first and last vertebrate classes to evolve?
What are the five fish vertebrate classes?
What are the defining characteristics of mammals?
What was the first class of vertebrates to live on land?
Sharks belong to what vertebrate class?

Image	Reference	Attributions
	[Figure 1]	Credit: Top to bottom: Bryce McQuillan; Dr. James P. McVey, NOAA Sea Grant Program; Scott Oves Source: Top to bottom: www.flickr.com/photos/spidermanbryce2006/1802722621/ ; www.photolib.noaa.gov/htmls/reef0206.htm ; http://www.flickr.com/photos/silicon640c/5968047195/ License: Top to bottom CC BY 2.0; Public Domain; CC BY 2.0
	[Figure 2]	License: CC BY-NC
	[Figure 3]	License: CC BY-NC
	[Figure 4]	License: CC BY-NC
	[Figure 5]	License: CC BY-NC
	[Figure 6]	License: CC BY-NC
	[Figure 7]	License: CC BY-NC
	[Figure 8]	License: CC BY-NC
	[Figure 9]	License: CC BY-NC
	[Figure 10]	License: CC BY-NC

The stingray. Fish?

Vertebrate Classification

Summary

Review

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