Zoology 465: Ichthyology

First Hour Exam, Spring 1997 Name___________________________

1. Define, as carefully as possible, how you would distinguish a fish from other known kinds of animals (5 points).

2. Name two geographic regions of the world you could visit and obtain unusually high measures of diversity in freshwater environments (4 points).

3. Briefly describe the life of a hagfish as we know it. Include physical environment, feeding, reproduction, behavior, and adult size reached. (10 points)

4. Matching. Note that each blank may need more than one answer. Provide all possible answers (23 points).

A. Lampetra, brook lamprey

B. Petromyzon, parasitic lamprey

C. Myxine, hagfish

D. all of the above

_____eats polychaete worms, among other dietary items

_____male attracts mates by secreting olfactory cues

_____rudimentary vertebral column (apparently absent) and cranium

_____lack true gill-arch jaws

_____length of body lined with slime pores

_____body fluid isosmotic with sea water

_____ammocoetes may live up to 18 years

_____adults die soon after spawning is completed

_____chondroitin 4-sulphate in cartilage

_____rarely exceeds 15 cm in length

_____neoteny or paedomorphosis may occur

_____spawns in ocean

_____numerous rows of strong, sharply pointed, keratinized teeth

_____distinctive barbels around mouth

_____eggs measure less than 1 mm in diameter

_____2 heme units

_____secrete lamphredin as an anticoagulant

_____never enters the ocean

_____development is direct

_____1 semicircular canal

5. Fill in the blanks or spaces with the appropriate information (20 points).

The world's fresh waters acount for approximately how much of the water on the planet_________? About what percentage of the earth's known fish fauna is presently confined to freshwater habitats?_________. What percentage of the earth's known fish fauna falls under the category of being diadromous?________. What 2 primary factors are thought to account for the diversity of freshwater fishes?

Placoid scales contain what three primary layers: ____________, ________________, ______________________? The first known fish fossils date to what geological time period

_______________________________? As ambryos, nearly all fish pass through a developmental phase in which they have ____________________________ caudal fin.

6. Using a diagram and words, illustrate and describe the zones of the ocean, providing details of physicial and chemical parameteres, major groups of fishes found in each zone, and special adaptations of fishes. Be specific and comprehensive (20 points).

7. Match the following. One best answer per blank (11 points).

A. sharks

B. skates, rays

C. none of the above

D. all of the above

E. A & B

_____neutral buoyancy is achieved via a gas bladder

_____external spiracle

_____all species are viviparous

_____claspers occur on pelvic fins of males only

_____cartilaginous endoskeleton

_____some species have caudal stinging spines

_____placoid scales in both young and adults

_____internal fertilization

_____average size reached is about 2 m

_____about 800 species are known

_____gill openings on ventral side of head

8. Draw a phylogenetic tree depicting the evolutionary branching sequence of major groups of "fishes." Groups that you must include are: 1) Myxini (hagfishes), 2) Cephalaspidomorphi (lampreys), 3) Coelacanthimorpha (Coelacanth), 4) Tetrapoda, 5) Dipnoi [=Dipneusti] (lungfishes), 6) Actinopterygii (rayfin fishes), 7) Chrondrichthyes (sharks + relatives). (7 points)