Lec 1 External Anatomy

Question 1

Fishes are animals that… 5

Answer 1

1. most always aquatic, 2. most always cold-blooded, 3. most always gill-breathing, 4. craniates, in which 5. fins are usually developed, never pentadactyl limbs

Question 2

Rover predators characteristics

Answer 2

Streamlined fishes, with pointed heads, terminal mouths, narrow caudal peduncles, and forked tails; always on the move in search of prey; pursuit predators; examples include salmon and trout (Salmonidae), basses

Question 3

Ambush predators

Answer 3

Fish-eaters designed for capturing fast-swimming prey by ambush, but these are also elongate, streamlined forms, often with flattened heads, large well-toothed mouths; the tail fin is large, dorsal and anal fins are placed far back on the body; examples include pikes (Esocidae), barracudas

Question 4

Surface-oriented fishes

Answer 4

Typically small fishes, with dorsally directed mouths, flattened heads, large dorsally directed eyes; examples include mosquitofishes (Poeciliidae), topminnows and killifishes

Question 5

Bottom fishes

Answer 5

Wide variety of body shapes, all adapted for contact with the bottom; most are flattened or compressed forms, with small, often subterminal mouths, and small eyes; examples are numerous: flatfishes (Pleuronectidae), catfishes

Question 6

Deep-bodied fishes

Answer 6

Laterally compressed forms, with short, deep bodies; dorsal and anal fins typically long; pectoral fins high on the body, with pelvic fins immediately below; small mouths, eyes large, snout short; examples include the huge variety of forms that inhabit coral and rocky reefs, kelp-bed forests

Question 7

Eel-like fishes

Answer 7

Elongate bodies, blunt heads, and tapering or rounded tails; paired fins sometimes absent, but when present, small; dorsal and anal fins typically running the length of the body; examples include the eels (Anguilli- formes), loaches (Cobitidae), pricklebacks

Question 8

Evolutionary trends

Answer 8

1. A shift in position of the paired fins (pectoral and pelvic fins) 2. An increase in overall spinyness (e.g., fins and scales) 3. Changes in body shape

Question 9

How does the pelvic and pectoral fins shift from primitive to derived?

Answer 9

Pelvic fin moves towards the head. Pectoral are moved middle and vertically in derived. Primitive is horizontal and low.

Question 10

Type of spiny scale: cycloid and ctenoid

Answer 10

Cycloid: spineless scales in primitive fishes
Ctenoid: spiny in scale, in derived

Question 11

How does body shape change from primitive to derived?

Answer 11

Long and skinny to short, fat and deep bodied

Question 12

What’s the primitive body plan?

Answer 12

Long, skinny head and body, fins placed posteriorly, without spines, generally large adult body size; built for speed in open water; examples might include tarpon, herring, sardines, anchovies, salmon and trout

Question 13

THE DERIVED FISH BODY PLAN

Answer 13

Short, deep head and body, fins placed far forward, full of spines, and generally small adult body size; built for maneuverability in complex, tight, crowded habitats; examples include squirrelfishes, cichlids, basses, surgeonfishes, angel and butterfly fishes, and a vast diversity of additional groups

Question 14

Speed and maneuverability trade off

Answer 14

Speed was, in a sense, sacrificed for greater maneuverability. Bodies became shorter and deeper, and fins, the dorsal and anal fins, but particularly the pelvic fins, shifted to a more anterior position on the body

Question 15

Reason for spiny ness?

Answer 15

Spiny scalation probably also evolved in response to the new rough, calcareous coral-reef habitat to better protect the body against abrasion

Question 16

superorder called the Acanthopterygii….

Answer 16

result that we see today is a tremendous diversity of fishes in the warm shallow seas of the world. And what’s important to realize is that nearly all the species that occupy these habitats belong to the most highly evolved group of bony fishes