Representative Organisms

SHARKS


Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha



Best known species :
• great white shark, tiger shark, and the hammerhead are apex predators, at the top of the underwater food chain.

Famous for:

• extraordinary skills as
• predators fascinate and frighten humans
• even as their survival is under serious threat from fishing and other human activities.


CHIMAERA
(http://en.wikipedia.org/wiki/Chimaera)


Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Holocephali
Order: Chimaeriformes

• They live in temperate ocean floors below approximately 2,600 metres (8,500 ft) depth, with few occurring at depths shallower than 200 metres (660 ft).
• known informally as ghost sharks, ratfish
• They may be the "oldest and most enigmatic groups of fishes alive today."[2] At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks, though in evolutionary terms they branched off from sharks nearly 400 million years ago and have remained isolated ever since, typically confined to deep water.[2] (interesting)
• They lack sharks' many sharp and replaceable teeth, having instead just three pairs of large permanent grinding tooth plates