Origin of Jaws in Fishes

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Questions and Answers

What is the characteristic of the mouth in agnathans?

It has a floor supported by the hyoid arch
It is neither defined nor supported by jaws (correct)
It has a roof supported by the splanchnocranium and lateral pharyngeal slits
It is defined and supported by jaws

What is the pattern of nerve and blood vessel distribution in jaws and branchial arches?

They are only present in jaws and not in branchial arches
They are distributed in a different pattern in jaws and branchial arches
They are distributed in a similar pattern in jaws and branchial arches (correct)
They are distributed in a random pattern

What is the origin of the musculature of the jaws according to the text?

It is transformed and modified from branchial arch musculature (correct)
It arises from the splanchnocranium
It develops from the neural crest
It is derived from the hyoid arch

What is the embryological evidence that supports the origin of jaws from gill arches?

The development of the jaws and branchial arches occur in series from neural crest (D) Signup and view all the answers

What is the main point of contention in the serial theory and the composite theory?

The number of branchial arches that gave rise to the mandibular arch (A) Signup and view all the answers

What is the conclusion regarding the origin of jaws from the evidence provided?

Jaws are derived from branchial arches (C) Signup and view all the answers

Who proposed the composite theory of the origin of jaws?

Erik Jarvik (A) Signup and view all the answers

What is the main difference between the serial theory and the composite theory?

The serial theory proposes a single branchial arch gave rise to the mandibular arch, while the composite theory proposes multiple branchial arches (D) Signup and view all the answers