Marine Biology
Chondrichthyes Web Quest
Name: _________________________________
Period: _________ Date: ______________
Introduction
Cartilaginous fishes (Class Chondrichthyes, from Greek chondros, cartilage, and ichthos, fish) are a class of aquatic, gill-breathing, finned vertebrates (animals with a vertebral column or `backbone'), equivalent to the bony fishes (Class Osteichthyes: osteos, bone, and ichthos, fish). Cartilaginous fishes include the living sharks, rays, and chimaeras, and have true upper and lower jaws, a sensory snout that overhangs the mouth and nostrils on the underside of the head, teeth in conspicuous transverse rows or in fused tooth plates that are replaced from inside the mouth, no bony plates on the head, scales in the form of small, tooth-like dermal denticles or placoid scales, fins without bony fin rays, and a simplified internal cartilaginous skeleton without bone.
There are over 900 named species of cartilaginous fishes, and at least 1100 known species including species new to science that are being described by researchers in museums and other research organizations. The living cartilaginous fishes are subdivided into two living groups, the large Subclass Elasmobranchii (elasmos, plates, and branchos, gills), which includes several groups of fossil sharks and the dominant Subcohort Neoselachii
(neos, new, and selachos, a shark) or `modern' SHARKS and RAYS, and the small Subclass Holocephali
(chimaeras). Modern sharks and rays (neoselachians) have 5 to 7 pairs of external gill slits, upper jaws not fused to the skull and usually capable of protrusion from the mouth, rows of teeth not fused into tooth plates, an erect 1st dorsal fin which cannot fold backwards, and no accessory claspers on the head or pelvic fins.
Purpose
The purpose of this activity is to describe the characteristics that separate Chondrichthyes from other fish-like chordates. In addition, you will be able to explain the characteristics that separate the different species of
Chondrichthyes from one another.
Directions (answer all questions on notebook paper and staple to this sheet.
1. Go to the following web page to read about the basic types of Chondrichthyes and answer the questions below, http://www.flmnh.ufl.edu/fish/education/questions/raybasics.html
a.
What is a ray? What is a skate? b.
What is an elasmobranch? c.
How long have rays and skates existed? d.
How many species of rays and skates have been described? e.
Are there different types of rays? f.
What is an electric ray? g.
Are all rays considered to be stingrays? h.
Are sawfish related to rays? i.
What are the differences between rays and skates? j.
What is the largest ray? What is the largest skate? k.
What is the smallest ray? What is the smallest skate? l.
Are rays and skates related to sharks? m.
Is it easy to distinguish rays and skates from sharks? n.
Where (in the world) do rays and skates live? o.
Are stingrays dangerous to humans? p.
Are skates dangerous to humans? q.
How can humans avoid being stung by stingrays? r.
Why do stingrays at public aquariums lack stinging spines? s.
Are rays and skates edible?

2. Use any web page to label the external anatomy of a shark.
3. You will now research about the following Chondrichthyes (Megalodon, Great White, Chimera, Electric
Ray, Big Skate, and Whale Shark) and record the following for each species on notebook paper: a.
Scientific name b.
General description c.
Coloration d.
Size e.
Feeding habits f.
Social groups g.
Habitat h.
Distribution i.
Migration j.
Attacks (attacks on people) k.
Status (endangered, protected, etc…)