chapter 41 section 1 Flashcards Preview

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Flashcards in chapter 41 section 1 Deck (15):
1

vertebral column

spine

2

cranium

skull

3

gill arch

skeletal elements that support the pharynx

4

mammal

class mammalia
have hair and nurse their young with milk

5

vertebrate characteristics

postanal tail
pharyngeal pouches
endoskeleton

6

skates belong to the class

chondricthyes

7

jawless fish

hagfish

8

earliest vertebrates were

jawless fishes with heavy, bony scales

9

The evolution of paired fins was important to early fishes because paired fins

increased the stability and maneuverability of the fishes

10

Jaws are thought to have evolved from the

first pair of gill arches

11

Compare and contrast modern jawless fishes with those that lived 500 million years ago

both groups lack jaws and paired fins. both have cartiliginous skeletons.
Early ones were covered with heavy, bony scales

12

Compare and contrast the skin of amphibians with the skin of reptiles.

The skin of amphibians is thin and permeable to
gases and water; the skin of reptiles is dry and scaly

13

Name the class to which horses belong, and describe two major characteristics of the animals in
that class

Horses belong to the class Mammalia; animals in
that class have hair and nurse their young.

14

What two important evolutionary events occurred in the acanthodians, or spiny fishes about 440 million years ago?

jaws and paired fins appeared

15

Explain why the class Chondrichthyes contains many more species than
the class agnatha

the jaws and paired fins of fishes in the class Chondrichthyes allow them to diversify into numberous species and be better predators