VERTEBRATE ZOOLOGY LAB

The Fishes - sharks and bony fishes

"WHAT IS A FISH?" VIDEO

1) View video.
2) Answer the following questions on a sheet of notebook paper:

First, state what you already know about fish in one or two complete sentences.

1. List and describe the three classes of living fish.

2. Describe how a fish's diverse body characteristics correlate with function.

3. Discuss the "theory" that all land animals evolved from fish. Include information regarding the following:
a. Is the above statement in #3 really a theory as defined by the scientific method? Why or why not?
b. If the information provided does not support this statement as "theory", what other terms may apply to that statement, again, as defined by the scientific method?
c. What type of evolution would result in the development of land animals from fish?
d. For such a transformation to occur, the evidence for such an event would be preserved in the fossil record as transitional forms; does the video describe any fossil evidence of transitional forms that would indicate evolution giving rise to land animals from fish?

4. Define the following:
a. denticles
b. gill bars
c. lobe fin
d. ray fin
e. coelacanth
f. swim bladder
g. camouflage
h. territoriality
i. symbiosis
j. parasite
k. protoplasm
l. neural tube

5. What body parts gave rise to sharks' jaws and teeth?

6. Explain the difference between lobe fins and ray fins.

7. How does a swim bladder work?

8. Describe three fish that have special body characteristics and explain how each characteristic is adapted to a particular function.

9. What type of evolution refers to the type of adaptations described in #8?

3) Try to answer questions during the video.
4) Time will be available to go back and answer missed questions toward the end of the lab period.

Cartilaginous (elasmobranch) fishes

• class Chondrichthyes - the dogfish shark, Squalus spp.
  • subclass Elasmobranchii
    • order Squaliformes

Anatomy:

• cartilaginous skeleton
• exposed gill slits
• very generalized vertebrate body plan
• basic structrual plan is also the basic embryonic plan of higher vertebrates
• grow to about 1 m in length

Habitat:

Drawings:

• Complete and label the outline of the external view in Fig. 19-4 ou your handout.
• Draw in and label the urinogenital organs as they appear in the pre-dissected specimen.

Taxonomy and sight recognition:

Bony fishes

• class Osteichthyes
  • subclass Actinopterygii
    • superorder Teleostei

Anatomy:

• bony skeleton
• covered gills (covered by ______________?)

Habitat:

Other characteristics of class Osteichthyes:

1. largest group of vertebrates in both number of spp. (>20,000) and number of individuals
2. found in both freshwater and marine habitats
3. found in both deep and shallow waters

Identify (on a preserved specimen) the following external structures and define, and list one function of each structure:
a. head
b. operculum
c. trunk
d. tail
e. pectoral, pelvic, anal, dorsal and caudal fins (note how many of each are present and which ones are paired and which ones are single)
f. fin rays (note which ones are bony and which ones are cartilaginous)
g. Is the caudal fin homocercal (both upper and lower halves alike) or heterocercal (upper and lower halves different)?
h. mouth
i. eyes (eyelids if present)
j. nostrils
k. lateral line
l. gills
m. anus
n. urinogenital opening
o. scales (determine which type, ctenoid, cycloid, or ganoid are present, if any)

List the components of each of the following skeletal sections: a. axial skeleton b. appendicular skeleton

Define the following muscle system elements:
a. myotome
b. epaxial muscles

Identify (on the pre-dissected specimen), define, and list a function of each of the following:
a. gill filaments
b. gill rakers

In the mouth, identify, define, andlist a function of the following:
a. gill slits
b. teeth
c. oral valves
d. tongue

In the abdominal cavity, identify, define and list a function of each of the following:
a. pericardial cavity
b. coelomic cavity
c. peritoneum
d. intestine
e. stomach
f. spleen
g. swim bladder
h. kidneys
l. the red body
m. oval capillary bed

Identify, define, and list a function of each of the following:
a. heart
b. ventral aorta
c. dorsal aorta

Drawings:

• Observe with a compound microscope prepared, whole mount (wm) slides of each of the following types of scales:
  a. ctenoid
  b. ganoid
  c. cycloid
• Make drawings of each scale type and provide a figure legend for each drawing.
• Identify on the pre-dissected specimen and label on the handout the following structures of the digestive system:
  a. esophagus
  b. cardiac portion of the stomach
  c. pyloric portion of the stomach
  d. pyloric valve
  e. duodenum
  f. pyloric ceca
  g. anus
  h. mesentery
  i. pancreas
  j. gallbladder
  k. swim bladder

Taxonomy and sight recognition:

1. Ictalurus natalis, yellow bullhead catfish

   Taxonomic aspects

   family Ictaluridae, catfish family

   Family characteristics

   scaleless bodies, broad flat heads, sharp heavy pectoral and dorsal spines, and long barbels about the mouth; mouth with numerous bristle-like teeth in the upper jaw; barbels are arranged in a pattern of four under the jaws, two above and one on each tip of the maxillary.

   Family distribution

   originally found in US only east of the Rockies, but now many spp. have been widely introduced in the wetern states.

   Economic significance

   all larger spp. are desirable food fishes.

   Anatomical characteristics of Ictalurus natalis, yellow bullhead catfish

   barbels under jaw white, not pigmented, color variable, back and sides various shades of brown to almost black; belly more or less yellow; anal rays 23 -27; lenght up to 18 inches.

   Distribution of Ictalurus natalis, yellow bullhead catfish

   North Dakota to Hudson River and south to Gulf; introduced elsewhere (Eddy & Underhill, 1978).

2. Betta splendens, bettas or fighting fishes

   Taxonomic aspects

   family Belontiidae (Polyacanthidae)

   subfamily Macropodinae

   Habitat and Distribution

   freshwater; west Africa, India, and Korea (Nelson, 1984).

Eddy S and Underhill JC (1978) How to know the freshwater fishes, 3rd ed., Wm. C. Brown Co., Dubuque, Iowa

Hickman FM and Hickman CP (1988) Laboratory studies in integrated Zoology, 7th ed., Times Mirror Ø Mosby College Publishing, St. Louis

Nelson JS (1984) Fishes of the world, 2nd ed., John Wiley & Sons, New York

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