Class Chondrichthyes Flashcards
What phylum is it in and subphylum?
Chordata and Vertebrata
What is the class that includes sharks, skates, rays, and chimaeras?
Chondrichthyes
What does Chondrichthyes mean?
cartilage fish
What type of body do sharks have?
Fusiform body
What type of caudal fin do sharks have?
Heterocercal caudal fin
What are the fins like?
paired pectoral & pelvic fins; one or two median dorsal fins
What is the mouth like?
ventral mouth; two olfactory sacs that do not connect to the mouth cavity; jaws present
What does the skin have?
placoid scales and mucous glands
What is the teeth like?
teeth of modified placoid scales
What is the endoskeleton made of?
cartilage
What is the digestive system like?
Digestive system with J-shaped stomach & intestine with spiral valve
what is the circulatory system like?
closed with two chambered heart (atrium and ventricle)
what is respiration like?
5 to 7 pairs of gills with separate and exposed gill slits; no operculum
What does it not have?
no swim bladder or lung
What are the senses like?
senses or smell, vibration reception (Lateral Line System), and electroreception well developed
What type of reproduction and fertilization do sharks have?
Oviparous with internal fertilization and direct development
What types of reproduction are there?
Oviparous (lay eggs), Ovoviviparous (live birth), and Viviparous (fertilization and embryo development occur inside the individual)
What is the most anterior part of the shark?
Rostrum
Sharks are naturally buoyant because they lack a _____ (they sink bc)
they lack a swim bladder
What do spiracles do?
allows water to pass through gills
What is in a shark’s digestive system that increases their surface area?
Spiral valve
What has to do with a shark’s sense of hearing and is behind the eyes connected to the inner ear
Endolymphatic pores
What is a shark’s sense of smell like?
-ventral nostrils not connected to mouth cavity
-most of the brain is dedicated to smell (large olfactory lobe)
What is the special receptor organs in a shark’s sense of distant touch called?
Neuromass
What are characteristics of a shark’s sense of vision?
-good vision even in dim lights
-they have stereotypical vertebrate eyes
-can’t see color bc. they lack cones for color vision & detail
What is the small jelly-filled pores in a shark’s sense of electroreception?
Ampullae of Lorenzini
What is the shark’s sense of electroreception?
-capable of detecting prey buried under sand
