Terry catches a ray-finned fish from the ocean and notices that attached to its flank is an equally long, snakelike organism. The attached organism has no external segmentation, no scales, a round mouth surrounded by a sucker, and two small eyes. Terry thinks it might be a marine leech, a hagfish, or a lamprey.
Which feature excludes the organism from possibly being a leech?
A) elongated shapeB) lack of scales
C) lack of external segmentation
D) round mouth
E) anterior sucker
Answer: C
Terry detaches the snakelike organism from the fish and uses a knife to cut off its head. In doing so, its brain slides out onto the deck of the boat. Terry peers into the cut end of the head and notices that the brain had lain in a sort of panlike structure that only partially surrounded the brain. What is the structure Terry is observing, and what is it made of?
A) skull, made of boneB) cranium, made of bone
C) cranium, made of cartilage
D) vertebral column, made of bone
E) vertebral column, made of cartilage
Answer: C
Terry takes the body of the snakelike organism and slices it open along its dorsal side. If it is a hagfish, what should Terry see?
A) a well-developed series of bony vertebrae surrounding the spinal cord
B) a well-developed series of cartilaginous vertebrae surrounding the spinal cord
C) a tube of cartilage (surrounding the notochord) with dorsal projections on both sides of the spinal cord
D) a notochord, located underneath the spinal cord
Answer: D
The snakelike organism turned out to be a hagfish. Consequently, why should Terry throw the fish to which the hagfish was attached overboard, rather than having it for dinner?
A) It has mucus on its skin.B) If it had an ectoparasite, then it must also have endoparasites.
C) The bite of the hagfish introduces paralytic neurotoxins, which Terry wants to avoid.
D) It was already sick or dying; otherwise, the hagfish would probably not have attacked it.
Answer: D
Having caught and handled a hagfish, what will Terry's shipmates most likely require Terry to do before returning to further fishing?
A) Wash his hands and then don gloves to prevent the spread of harmful microbes that live only on hagfish skin.B) Clean the bucketsful of hagfish slime from the deck of the boat.
C) Dispose of the fishing tackle that had been poisoned by coming into contact with the hagfish.
D) Cut up the remaining hagfish and share pieces of this highly sought-after baitfish.
Answer: B
Terry saved some of the tooth-like objects within the hagfish's round mouth to analyze their composition in his mentor's biochemistry research lab. Terry will find that they are composed of the same protein found in tetrapod
A) skin.B) teeth.
C) bones.
D) cartilage.
E) muscles.
Answer: A
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