Chapter 20

Question 1

What does the name osteichthyes refer to?

Answer 1

Bony fish

Question 2

Compare bone versus cartilage including advantages and disadvantages.

Answer 2

Bone
-stronger : better protection and structural support *advantage
-less flexible (stiff) *disadvantage
-heavier : more energy expenditure for movement and floatation *disadvantage
-better blood supply : heals faster *advantage

Cartilage
-flexible and lightweight *advantage
-doesn’t heal fast *disadvantage
-no protection or structural support *disadvantage

Question 3

What are the three groups of fishes included within Osteichthyes?

Answer 3

Ray-finned fishes (Actinopterygii), lobe-finned fishes (coelacanths, lungfishes)

Question 4

What is the main difference between the coelacanths plus lungfishes and the ray-finned fishes?

Answer 4

Lobe-finned fishes (coelacanths & lungfishes) have a lobe with bones that are homologous with tetrapods while ray-finned fishes do not have a lobe or the homologous bones.

Question 5

What are homologous structures?

Answer 5

Similar trait or characteristics from a common ancestor

Question 6

What are fin rays?

Answer 6

A bony element that supports fin membranes

Question 7

How do fin rays relate to the taxonomic name Actinopterygii?

Answer 7

Fin rays relate to the name Actinopterygii because the fins in these animals are supported by fin rays (spines or soft rays or both)

Question 8

List the two types of fin rays, their characteristics and function

Answer 8

SPINES
Characteristic
-unsegmented, unbranched, hard
Function
-protection & structural support
SOFT RAYS
Characteristic
-segmented, branched, flexible
Function
-maneuverability

Question 9

What are the two main functions of scales?

Answer 9

Protection, hydrodynamics (easier to swim)

Question 10

What evolutionary trend is evident regarding the number and size of the scales in many groups of bony fishes?

Answer 10

Decrease in number and size of the scales during evolution.
Large, heavy, bony plates -> small, lightweight scales -> no scales

Question 11

List and define the 4 main body shapes found in bony fishes.

Answer 11

Anguilliform, compressiform, fusiform, and globiform (globular).

Question 12

Fusiform

Answer 12

Torpedo shaped body, efficient for swimming (e.g. tuna & billfishes

Question 13

Anguilliform

Answer 13

Eel shape body, energy efficient, not fast, fit in tight places (e.g. eels)

Question 14

Compressiform

Answer 14

Compressed body shape laterally or dorso-ventrally flattened, hard to see, fit into small places (e.g. many coral reef fishes & flatfishes)

Question 15

Globiform

Answer 15

Global shaped body (e.g. porcupinefish)

Question 16

List and define the 5 main coloration patterns found in bony fishes

Answer 16

Cryptic, disruptive, advertisement, ocelli and countershading.

Question 17

Cryptic

Answer 17

Blending in with the environment (camouflage)

Question 18

Advertisement

Answer 18

Sexual selection (flashy colors to show off male sex) bight colors in males show they are healthy and have the best genes for survival

Question 19

Disruptive

Answer 19

Break the outline of body so predators cannot tell what they are (striped fish-> dark light shows only the light color of the stripes, light light shows only the dark color of the stripes -> confuses predator)

Question 20

Ocelli

Answer 20

False eye spots (a spot on fish that looks like an eye to trick predators that the head is located there)

Question 21

Countershading

Answer 21

Pelagic fishes (dark while looking down on the fish, light while looking up at the fish = camouflage)

Question 22

What is the lateral line system?

Answer 22

-Sensory system that detects vibrations in water.
-It is a series of canals with pores and neuromasts (cupola & cilia).
-Signal to brain depends on the direction of bending of the cilia.

Question 23

What are neuromasts?

Answer 23

-A sensory organ in the lateral line system.
-It is made of cupola and cilia that moves with water movement that enters the canal of the lateral line through the lateral line pore.

Question 24

What are the main functions of the lateral line system?

Answer 24

To detect vibration in the water
-schooling (pack of fishes moving together)
-from predators
-from prey
-from obstacles

Question 25

Gonochorism

Answer 25

Only one sex, either female or male NOT both.

Question 26

Sequential hermaphroditism vs simultaneous hermaphroditism

Answer 26

Hermaphroditism-> both sexes Sequential-> change sex during life Simultaneous-> male and female at the same time *DO NOT FERTILIZE YOURSELF!

Question 27

Protandry

Answer 27

Male -> female (e.g. clownfish) *good for monogamous(one partner) relationships -> bigger female fish to produce mor eggs *when elder female dies oldest male turns into a female

Question 28

Protogyny

Answer 28

Female -> male (e.g. parrot fishes) *good for polygamous(more than one partner) -> one male mates w/ multiple females *fishes that were able to survive long enough to become a male = better genes for survival -> pass on genes as male *male sneakers (adult males that look like juveniles) -> evolved to look like juveniles so they can mate with females without competing with the big male adults b/c they think they are juveniles

Question 29

Sexual dimorphism

Answer 29

Two shapes or forms *external characteristics -> define if male or female

Question 30

Broadcast spawning

Answer 30

Male squirts sperm into water, female either relates their eggs or keep them

Question 31

Describe why the discovery of the first coelacanth was so important

Answer 31

It was thought that coelacanth were extinct for 65 million years ago with the dinosaurs.

Question 32

When and where was the first coelacanth discovered?

Answer 32

In 1938 Marjorie Courtenay-Latimer found one in South Africa

Question 33

What is the genus name of this animal in honor of?

Answer 33

The genus name Latimeria chalumnae is in honor of the women who found it, Marjorie Courtenay-Latimer

Question 34

How many living species of coelacanths have been described so far?

Answer 34

Two living species have been described so far

Question 35

What do we mean when we say that coelacanths are “living fossils”?

Answer 35

It means that the species is still alive today

Question 36

What are the closest living relatives to the tetrapods?

Answer 36

Lungfishes

Question 37

What does the word “tetrapod” refer to?

Answer 37

Four legs

Question 38

Name the 3 groups of tetrapods.

Answer 38

Amphibians, Reptiles, and Mammals

Question 39

Where are lungfishes found today?

Answer 39

Africa, South American, and Australia

Question 40

What is unique about the anatomy of lungfishes?

Answer 40

That they have lungs and gills, meaning they can breathe in and out of the water