13
1 Class: Chondrichthyes - Sharks and Rays The shark’s skeleton is entirely composed of cartilage. The skin is covered with tiny scales called denticles. They are similar in structure to teeth and cause the skin to be very abrasive if rubbed in the wrong direction. Most have gray, brown, white or black coloring; are not camouflaged but may be counter-shaded. Only predators are toothed whales and man. Puffer fish can accidentally suffocate a shark by blocking water from entering the gills resulting in death for both.

Class : Chondrichthyes - Sharks and Rays

  • Upload
    phiala

  • View
    71

  • Download
    0

Embed Size (px)

DESCRIPTION

Class : Chondrichthyes - Sharks and Rays. The shark’s skeleton is entirely composed of cartilage. The skin is covered with tiny scales called denticles. They are similar in structure to teeth and cause the skin to be very abrasive if rubbed in the wrong direction. - PowerPoint PPT Presentation

Citation preview

Page 1: Class :  Chondrichthyes  - Sharks and Rays

1

Class: Chondrichthyes - Sharks and Rays

The shark’s skeleton is entirely composed of cartilage.

The skin is covered with tiny scales called denticles.

They are similar in structure to teeth and cause the skin to be very abrasive if rubbed in the wrong direction.

Most have gray, brown, white or black coloring; are not camouflaged but may be counter-shaded.

Only predators are toothed whales and man. Puffer fish can accidentally suffocate a shark by blocking water from entering the gills resulting in death for both.

Page 2: Class :  Chondrichthyes  - Sharks and Rays

2

Page 3: Class :  Chondrichthyes  - Sharks and Rays

3

Predation: Efficient, top carnivore of the sick, weak, old and injured.

Jaw is lined with rows of teeth like a conveyor belt (modified scales).

Teeth can be replaced every 24 hours and are used to identify species.

Jaw can be extended out of the mouth for extra reach.

Page 4: Class :  Chondrichthyes  - Sharks and Rays

4

Circulation: 2 chambered heart; cold-blooded

Sharks lack swim bladders (have oily livers) and must constantly swim upwards to balance their weight.They do sleep.

Respiration: Gills are located in muscular slits (gill slits, no operculum) behind the mouth.They exchange oxygen from the water into the blood.

Page 5: Class :  Chondrichthyes  - Sharks and Rays

5

SHARK BODY SHAPE - fusiform

SHARK FINS - Pectoral – FixedCaudal Fin – longer upper lobe

Page 6: Class :  Chondrichthyes  - Sharks and Rays

6

Senses: Vision is good in clear water. Eyelids close from the bottom upwards to prevent injury during an attack.

Smell is excellent. Olfactory lobes compose 2/3 of the brain. Sharks can detect a drop of blood 1/4 mile away in the water and can determine the direction of the source.

Hearing is excellent. Sound vibrations can be detected by the lateral line from 3,000 feet away.

The electrical impulses of breathing from a prey can be picked up through pores in the face (ampullae of Lorenzini).

Page 7: Class :  Chondrichthyes  - Sharks and Rays

7

Reproduction: sexual, internal fertilization. Most sharks have live births - dogfish have 4-10 pups, tiger sharks may have 80-100 at one time. A few species lay eggs.

Page 8: Class :  Chondrichthyes  - Sharks and Rays

8

Shark attacks on humans are rare, but with more people in the water the odds are increased.

Sharks may be looking for new food sources due to over fishing.

Most attacks occur in less than 6 feet of water, at dawn or dusk, during summer months. Risks are also increased for surfers and swimmers in water with reduced visibility.

A surfer in black wet-suit, paddling out on a board, may look enough like a seal to interest a shark.

Page 9: Class :  Chondrichthyes  - Sharks and Rays

9

Most attacks occur in Florida, California, Australia, and Africa. Florida has 4 times the number reported in California. Most attacks are not fatal.

Sharks only kill less than 2 people worldwide per year. 548 fatalities since 1580Bees kill hundreds of people and crocodile/alligator - related deaths number nearly 1000.

People have done far greater damage to the shark population.

Page 10: Class :  Chondrichthyes  - Sharks and Rays

10

Page 11: Class :  Chondrichthyes  - Sharks and Rays

11

The whale shark is over 50 feet long. It is a filter-feeder with baleen instead of teeth.

Largest shark

Most dangerousGreat White sharks are found in the temperate and tropical oceans worldwide.

Track Mary Lee

Page 12: Class :  Chondrichthyes  - Sharks and Rays

12

FINNING

Page 13: Class :  Chondrichthyes  - Sharks and Rays

13

Largest ray

Manta Rays may have a 25 foot wide wing span.

Most dangerous

Sting Rays have a venomous stinger in their tail. Shuffle your feet when wading to avoid stepping on it.