Bio 123: PP16 Material Flashcards
What starts the class of fish?
Chondrichthyes
What are the sub classes to Chondrichthyes?
Holocephali and elasmobranchii
What is a unique characteristic we begin to see with Chondrichthyes?
They begin to have jaws.
What is the study of fish?
Ichthyology
-Chon
means having cartilage
What is the purpose of having pointed bodies?
It allows for efficient hydrodynamic movement
What are some characteristics of Chondrichthyes?
-about 900 species
-Cartilaginous skeleton
-oily liver
-5-7 pairs of external gill slits
-3 pairs of semicircular canals
-Almost all viviparous
-two chambered heart
-heterocercal caudal fin
-pelvic claspers
-placoid scales
-ventral. outh and polyphydont teeth
What is the purpose of the liver in chondrichthyes??
It plays a dual function where it takes care of toxins in the body and regulate fat. It is also now full of vacuoles that help it maintain buoyancy.
Viviparous
giving birth to live young
oviparous
being born from an egg
What is the purpose of pelvic claspers?
Helps male sharks keep female sharks in place since they are not as willing to mate. The claspers attach to the females and inflict pain if they begin to move too much or try to fight the male sharks.
Define polyphydont teeth in sharks
They keep constantly growing where older teeth are in the front and newer teeth are in the back.
What are the variations of the caudal fin?
Heterocercal (shark)
Diphycercal (lungfish)
Homocercal (perch)
What is the ancestral form of the caudal fin?
The heterocercal tail
What are the variations of scales in fish?
-Placoid scales (cartilaginous fishes)
-Ganoid scales (nonteleost bony fishes)
-Cycloid scales (teleost fishes)
-Ctenoid scales (teleost fishes)
What is the ancestral scale form?
Having placoid scales
Atrium
top chamber of the heart
ventricle
bottom chamber of the heart
Heterocercal
asymmetrical tail
Homocercal
Having a symmetrical tail