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CHAPTER 38 ACTIVE READING WORKSHEETS
ECHINODERMS AND INVERTEBRATE CHORDATES
Section 38-2: Invertebrate Chordates
Read the passage below, which covers topics from your textbook. Answer the questions that follow.
1 In addition to a notochord, all chordates have the following characteristics during some stage of their life: a dorsal nerve cord, pharyngeal pouches, and a postanal tail. 2 Unlike the ventral nerve cords of invertebrates such as annelids and arthropods, the dorsal nerve cord of a chordate is a hollow tube. 3 In vertebrates, the anterior end of the nerve cord enlarges during development to form the brain, and the posterior end forms the spinal cord. 4 The brain receives information from a variety of complex sensory organs, many of which are concentrated at the anterior end of the body. 5 The pharyngeal pouches are outside pockets in the pharynx, the portion of the digestive tract between the mouth and the esophagus. 6 In aquatic chordates, the pharyngeal pouches became perforated by slits and evolved first into filter-feeding structures and later into gill chambers. 7 In terrestrial chordates, the pouches evolved into a variety of structures, including the jaws and inner ear. 8 The notochord or backbone extends into the postanal tail, and muscles in the tail can cause it to bend. 9 The postanal tail provides much of the propulsion in many aquatic chordates. 10 Invertebrates in other phyla lack this form of propulsion, because the anus, if present, is located at the end of the body.
Read each question and write your answer in the space provided.
SKILL:Recognizing Text Structure
1.What text structure did the author use in this passage?
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2.What does Sentence 5 describe to the reader?
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3.In Sentences 6 and 7, what trait of aquatic chordates and terrestrial chordates is shown to differ?
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4.According to Sentences 6 and 7, how are the gill chambers of aquatic chordates similar to the inner ear of terrestrial chordates?
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Write your answers in the spaces provided.
SKILL:Interpreting Graphics
5.The diagram shows structures common to all chordates. Complete the diagram by inserting the following labels: “Dorsal nerve cord,” “Postanal tail,” “Notochord,” and “Pharyngeal pouch.”
Read the question and write your answer in the space provided.
SKILL:Vocabulary Development
6.What is the meaning of the term perforated in the passage?
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Circle the letter of the word that best completes the analogy.
7.In reference to the vertebrate nerve cord, posterior is to spinal cord as anterior is to
a.esophagus.
b.mouth.
c.brain.
d.Both (a) and (b)
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Modern Biology1Invertebrate Chordates