Lecture 3: Chondricthyes Flashcards
Which of the following statements is true regarding Ostracoderms and Placoderms?
A) Ostracoderms were heavily armored jawless fish, while Placoderms were bony fish with scales.
B) Ostracoderms were bony fish with scales, while Placoderms were heavily armored jawless fish.
C) Both Ostracoderms and Placoderms were heavily armored jawless fish.
D) Both Ostracoderms and Placoderms were bony fish with scales.
Option A) “Ostracoderms were heavily armored jawless fish, while Placoderms were bony fish with scales,” is the correct statement.
Which of the following is an example of an extinct agnathan (jawless fish)?
A) Placoderms
B) Acanthodians
C) Ostracoderms
D) Actinopterygii
c) Ostracoderms!
Which of the following is an example of an extinct jawed fish belonging to the class Chondrichthyes?
A) Cladoselache
B) Placoderm
C) Acanthodes
D) Eusthenopteron
b) Placoderm
What anatomical feature helps sharks with lift and balance in water?
A) Heterocercal tail
B) Diphycercal tail
C) Homocercal tail
D) Swim bladder
E) None of the above
A) Heterocercal tail
Which two ancient groups are considered early jawed fish?
A) Acanthodii and Agnatha
B) Placoderms and Actinopterygii
C) Acanthodii and Placoderms
D) Agnatha and Chondrichthyes
c) Acanthodii & Placoderms
What common anatomical feature do placoderms and ostracoderms have in common?
A) Presence of cartilaginous skeleton
B) Heavily armored body
C) Lack of paired fins
D) Absence of a swim bladder
E) Bony head shield
E) bony head shield
During which period and era did the placoderms emerge?
A) Paleozoic Era, Devonian Period
B) Mesozoic Era, Triassic Period
C) Cenozoic Era, Pleistocene Period
D) Paleozoic Era, Ordovician Period
E) Paleozoic era, Silurian Period
E) Paleozoic Era, Silurian period
During which geological period did the placoderms go extinct?
A) Devonian Period
B) Silurian Period
C) Carboniferous Period
D) Permian Period
A) Devonian period
True or False?
Placoderms did not have a vertebral coloumn
true !
Which of the following are living subclasses of Chondrichthyes?
A) Holocephali and Actinistia
B) Elassobranchii and Myxini
C) Holocephali and Elasmobranchii
D) Actinopterygii and Dipnoi
C) Holocephalii & Elasmobranchii
True or False?
Agnathans have no presence of bone except for their placoid scales and teeth
True!
Subclass: Holocephalii
- Class: Chondricthyes
- Chimeras (ratfish)
- have operculum on the head
- cephalic clasper on head
Subclass: Elasmobrachii
- Class: Chondricthyes
- Sharks, rays & skates
What significant change occurs in the jaws of Elasmobranchii, particularly in sharks, as they transition from jawless fish to jawed fish?
A) The jaws become smaller and less pronounced.
B) The jaws retract into the mouth cavity.
C) The jaws protrude outward, becoming more defined and movable.
D) The jaws become cartilaginous instead of bony.
c) the jaws protrude outwards, becoming more defined and flexible
What sensory adaptation do sharks possess to detect electrical impulses, such as muscle contractions of prey?
A) Lateral line system
B) Olfactory bulbs
C) Ampullae of Lorenzini
D) Jacobson’s organ
c) Ampullae of Lorenzini
