Page 28 - Science Course 2 (Book 1)

Mo1-L3: Key Concept Organizer

Directions: Circle the term in parentheses that correctly completes each sentence.

1. Mammals are (invertebrate chordates/vertebrate chordates).

2. A vertebrate is an animal that (has/does not have) a backbone.

3. All chordates have (pharyngeal pouches/notochords), which are flexible rod-shaped structures that support
the body of a developing chordate.
4. In vertebrate chordates, the notochord is eventually replaced by the (backbone/tailbone).

5. All chordates have or have had tails; in humans, the (backbone/tailbone) is the remnant of the tail.
6. All chordates have nerve cords; in humans, the nerve cord develops into the (heart/brain) and spinal cord.

7. All chordates have (pharyngeal pouches/notochords), which are grooves along the side of a developing
chordate.

8. In humans, the pharyngeal pouches develop into parts of the (head and neck/arms and legs).

9. In fish, the pharyngeal slits provide support for (lungs/gills).

Mo1-L3: Key Concept Check

Directions: On the line before each type of animal, write I if the animal is an invertebrate chordate or V if
the animal is a vertebrate chordate.

1. reptile 2. mammal
3. tunicate 4. bird
5. lancelet 6. amphibian

Directions: Answer each question on the lines provided.

7. You are trying to identify an animal. What characteristics would help you determine if the animal is a
chordate?

8. How could you determine whether the animal is an invertebrate chordate or a vertebrate chordate?

9. What test could determine how closely related the animal is to other kinds of chordates?

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