Cartilaginous Fish
Handout
Characteristics:
1. The skeleton of the cartilaginous fish is out of a flexible bone- cartilage. The skeleton does not have any bone.
2.These fish have dorsal fins, an anal fin, a pair of ventral fins and a single caudal fin.
3.The swim bladder and lungs are absent and the liver is filled with oil to provide buoyancy to the body while swimming.
4.The heart consists of two chambers like other fish and amphibians.
5.The cartilaginous fish habitat comprises mostly of creeks and rocks where they can get their prey easily. Sharks are mostly found near the seabed.
6.These fish have jaws which have tiny teeth, with the upper row of teeth having a layer of enamel and the lower row of teeth is made up of bone tissue, which attaches them to the skin. The teeth are modified and are replaced by new teeth, when the older ones become worn out.
7.Sharks and stingrays have an opening, called spiracle or gill slits that is situated on both sides of the head right behind the eyes, for breathing.
8.The pectoral fins of the shark are called claspers and used for copulation. There are three ways in which sharks reproduce; oviparous, where the female lays eggs which takes a few months to develop, ovoviviparous, where the eggs are hatched in the oviduct and the embryo develops in the uterus and viviparous, in which the gestation period of the embryo is about one year.
9.The sharks feed on other sea animals like zoo plankton, other smaller fish, whales and shellfish, etc.
Food:
Cartilaginous fish live in the sea. They are most common in warm seas. There habitat varies from the different type. Some live in the depths of the seas, and some near the surface. Some live in coastal waters, and some far out at sea. Most of the cartilaginous fish are carnivores. What they eat ranges from small worms and mussels to large fast swimming fish and marine animals. The sharks also eat their own kind. There are fewer than 100 attacks on humans a year from cartilaginous fish
Name:
Class Chondrichthyes means the jawed, cartilaginous fish with a flexible skeleton made of cartilage.
Representative Organism:
SHARKS
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
They live in temperate ocean floors below approximately 2,600 metres depth, with few occurring at depths shallower than 200 metres
• known informally as ghost sharks, ratfish
• They may be the "oldest and most enigmatic groups of fishes alive todayAt one time a "diverse and abundant" group 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
• They lack sharks' many sharp and replaceable teeth, having instead just three pairs of large permanent grinding tooth plates
Vocabulary:
Enamel-the hard white outer layer of teeth
Spiracle- an opening that is situated on both sides of the head right behind the eyes, for breathing.
claspers- The pectoral fins of the shark used for copulation.
gill- one of the organs behind the head of a fish that allows it to breathe
medulla oblongata- the lowest part of your brain that is connected to your spinal cord and controls the way that your heart and lungs work
olfactory- relating to your sense of smell
