Flashcards in chapter 41 section 1 Deck (15):
skeletal elements that support the pharynx
have hair and nurse their young with milk
skates belong to the class
earliest vertebrates were
jawless fishes with heavy, bony scales
The evolution of paired fins was important to early fishes because paired fins
increased the stability and maneuverability of the fishes
Jaws are thought to have evolved from the
first pair of gill arches
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
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
Name the class to which horses belong, and describe two major characteristics of the animals in
Horses belong to the class Mammalia; animals in
that class have hair and nurse their young.
What two important evolutionary events occurred in the acanthodians, or spiny fishes about 440 million years ago?
jaws and paired fins appeared