Chapter 3: Early Vertebrates - Jawless Vertebrates and the Origin of Jawed Vertebrates Flashcards
Define Viviparous
Live birth
Define Oviparous
Lay eggs
What were ostracoderms?
Animals that were very different from any vertebrate alive today. They were fish encased in bony armor.
What are the 4 groups of jawed fish?
1) Chondrichthyes (cartilaginous)
2) Osteichthyans (bony)
3) Placoderms (known for thick, bony shield)
4) Acanthodians (known for their stout spines)
3 and 4 are extinct
Name the 3 main functions of a jaw.
1) Respiration
2) Maneuvering of prey
3) Feeding
What is Enamel and Dentine?
Mineralized tissues primarily in the teeth among living vertebrates that are as old as bone
What were ostracoderms used for?
A defensive structure against attacks from predators and a protective and insulating coating around the electroreceptors that enhances detection of prey
What is a Conodont?
Spinelike or comblike structures composed of apatite (toothlike elements of true vertebrates)
What serves as a store of calcium and phosphorous?
Bone
Why are Hagfish and Lampreys linked as cyclostomes?
They have round, jawless mouths
Hagfish are found where?
In the deep, cold parts of the sea floor
What defensive feature to hagfishes posses?
Slime
Lampreys are…?
Parasitic
Why are fins important?
They act as hydrofoils that apply pressure to the surrounding water.
A tail fin gives more thrust during propulsion.
Pectoral/pelvic fins tilt the fish up and down and act as brakes
True or false
Fins are only used for locomotion.
FALSE
They can also be used for defense (spiny fins can inject poison) and visual signals (colorful fins help find mates or warn predators)
True or false
Vertebrates jaws are made of the same material as the skeletal elements that support the tills (cartilage derived from the neural crest)
True
What are Placoderms covered with?
Thick, ornamented bony shield that’s divided into separate head and trunk portions linked by a mobile joint that allowed the head to be lifted up during feeding
Most placoderms are?
Flattened, bottom-dwelling forms
Acanthodians have…
Slender, fusiform shaped bodies with a large head and wide-gaping mouths
Who do Acanthodians resemble?
Chondrichthyes because they have spines associated with their fins and have teeth forming a sharklike tooth whorl rather than being embedded in the jaws
Fossil evidence showed that vertebrates first evolved in what environment?
Marine
Why did jaws evolve?
To improve fill ventilation rather than to bite prey
