Modern fishes include an estimated 31,000 species, by far the most of all clades within the Vertebrata. Fishes were the earliest vertebrates, with jawless species being the earliest forms and jawed species evolving later. They are active feeders, rather than sessile, suspension feeders. The Agnatha (jawless fishes)\u2014the hagfishes and lampreys\u2014have a distinct cranium and complex sense organs including eyes, that distinguish them from the invertebrate chordates, the urochordates and cephalochordates.<\/p>\r\n\r\n Modern fishes include an estimated 31,000 species, by far the most of all clades within the Vertebrata. Fishes were the earliest vertebrates, with jawless species being the earliest forms and jawed species evolving later. They are active feeders, rather than sessile, suspension feeders. The Agnatha (jawless fishes)\u2014the hagfishes and lampreys\u2014have a distinct cranium and complex sense organs including eyes, that distinguish them from the invertebrate chordates, the urochordates and cephalochordates.<\/p>\n The learning activities for this section include the following:<\/p>\nWhat You\u2019ll Learn to Do<\/h2>\r\n
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Learning Activities<\/h3>\r\nThe learning activities for this section include the following:\r\n
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Identify characteristics of fishes<\/h2>\n
What You\u2019ll Learn to Do<\/h2>\n
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Learning Activities<\/h3>\n
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Candela Citations<\/h3>\n\t\t\t\t\t