Chondrichthyes (Sharks) Flashcards
what does chondrithyes mean?
cartilage fish
what are some characteristics about condrichthyes
- cartilaginous skeleton
- paced scales
- teeth replacement
- no gas bladder
- spiracle
- variation on jaw suspension
what is special about sharks?
they are secondary cartilaginous
- they ancestors were bony and now they are not cartilage is mineralized
what kind of scales do shark have?
placoid scales
- made with enamel and dentine
how do sharks teeth replacement work?
they come from within the mouth like a conveyer belt
what are the 4 types of jaw suspension sharks use?
- autodistylic
- amphistylic
- holostylic
- hyostylic
explain autodiastylic jaw
there’s 2 connection points between the upper jaw and chondrocraium
- lower job is connected to the upper jaw
explain amiphistylic jaw
upper jaw is attached by 1 ligament and suspended by hyomadibula
explain holostylic jaw
upper jaw is fused to chonrocraimium
explain hyostylic jaw
1 connection point but strong support from hyomandibula
- jaw can pop out
explain the sensory system of sharks
vision
- good at low light
chemoreception
- high sensitivity to smell
electroreception
- ampullae of lorenzini on the tip of their face allows them to sense electricity from muscles and water
lateral line
- cluster of cells that can detect movement of other fish
what are the lineages of sharks?
- holocephacii
- selachi
- batoida
- early elasmobranchs
explain the characteristics of holocephacii sharks
(type of jaw, feeding, reprodcution)
aka ratfish or chimera
- holostylic jaw
- oviparous
- bottom feeder
- no spiracle
explain the characteristics of the early elasmobranchs (type of jaw, feeding, reprodcution)
fast swimming apex
- amphistylic jaw
- spikes
explain the characteristics of selachi
hammer heads
- hyostylic
- oviparous
- subterminal head
