Chapter 24: Fishes, Osteichthyes: Bony fishes

Question 1

Is this a valid taxon?

Answer 1

No it is just term of convenience

Question 2

What were the two lineages that are under this category that developed during the middle of the Devonian?

Answer 2

• Class Actinopterygii- ray finned fishes radiated to form modern bony fishes
• Class Sacropterygii- lobe finned fishes which include lungfishes and the coelacanth

Question 3

What does the operculum function as?

Answer 3

• increased respiratory efficiency via drawing water across gills

Question 4

What do the gas filled structure off the esophagus function in? What two variations are there?

Answer 4

• helped in buoyancy and also in hypoxic waters
• Some fishes use these for respiration , they are called lungs in that case
• those that use it for buoyancy they are called swim bladders

Question 5

Specialization of jaw musculature improved what?

Answer 5

• feeding