BioEE274_Exam_1_2008_key-1 - TheVertebrates(BioEE274) Name:

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The Vertebrates (BioEE274) Name: Exam 1 – February 21, 2008 Please write your name on every page of this exam. Good Luck! 1. Indicate which of the following statements are true (T) and which are false (F). (2 pts. each) T Anadromy is more common than catadromy. T A three-part body is a shared derived characteristic of acorn worms and pterobranchs. F During human development, most tissues and organs begin to form during the fetal period. F Pharyngeal slits are a shared derived characteristic of chordates. F Larval and adult tunicates have a dorsal, hollow nerve cord. T Most species of living craniates are ray-finned fishes. F Larval lampreys use cilia to move water when filter-feeding. T Most vertebrates other than mammals have homodont and polyphyodont dentition. F Internal fertilization is the plesiomorphic condition for vertebrates. T Stem groups have only some of the derived characteristics of extant species. T The dermis is found in craniates, but not in invertebrate chordates. T The scales of bony fishes grow with the fish, but those of cartilaginous fishes do not. F Bones of the dermal skeleton develop via endochondral ossification. T Birds and mammals differ from other craniates in having determinate growth. 2. Compare and contrast neural crest and neurogenic placodes . (8 pts.) Both neural crest and neurogenic placodes are embryonic tissues that give rise to nerve cells and sense organs (for this reason they are called neurogenic tissues). They are migratory cells derived from ectoderm. Although they share many functions, there are some differences. For example, neural crest cells (but not neurogenic placodes) form motor neurons and glial cells. Neurogenic placodes (but not neural crest cells) form sensory receptors (e.g., olfactory epithelium). 3. How do the “jaws” and “teeth” of hagfishes differ from those of gnathostomes? (8 pts.) In hagfishes, the “teeth” are made of the protein keratin; they are not derived from the epidermis, dermis and neural crest as are the true teeth of gnathostomes (outer layer of enamel from epidermis; inner layer of dentine from dermis). The “jaws” of hagfishes consist of a dental plate bearing the “teeth”; the jaws open sideways (in the horizontal plane) rather than up and down as in gnathostomes. Further notes on gnathostome jaws: derived from neural crest and thought to have arisen from an anterior gill arch. 1
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Name: 4. Define, in one or two complete sentences, the following terms: (6 pts. each) Paraphyletic group - A group containing the ancestor and only some of its descendants. Gastrulation -
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This note was uploaded on 02/23/2009 for the course BIOEE 2740 taught by Professor Zamudio,k. during the Spring '07 term at Cornell University (Engineering School).

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BioEE274_Exam_1_2008_key-1 - TheVertebrates(BioEE274) Name:

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