Shark

  

Characteristics

·         Fusiform body or dorosventrally depressed

·         Paired pectoral/pelvic fins and two dorsal fins

·         In male under pelvic fins, there are caspers for releasing gametes to water.

·         Skin with placoid scales.

·         Endoskeleton entirely cartilaginous.

·         Digestive system with J shaped stomach.

·         4 chambered heart.

·         No swimming bladder or heart.

·         Excretion product is urea(To prevent water loss)

·         Sense of smell, vibration reception (lateral line system), vision and electroreception well developed.

·         Inner ear open to outside by end lymphatic duct.

·         Sexes are separate.

·         Paired gonads.

·         Internal fertilization.

·         Oviparous/Viviparous/Oviviparous

Idenitifical featuers

·         Ventral mouth

·         Caudal fin is heteroceral

·         1^st caudal fin is triangular.

·         5 Paris of gills.

·         A paired rostrum.

·         Long, laterally compressed and spindle shaped at both ends

Sharks are very good at adapting to new situations and environments which is why they have survived in the water for millions of years.

The habitat of a shark depends on the species though. Sharks are cold blooded, and that would usually imply that they would search for areas where the temperatures are very cold. However that is not true as there are sharks living in warm, temperate and cold waters.Sharks depend on their senses to help them survive in their natural habitat. Therefore, most of the shark senses are highly developed and efficient .

Sharks engage in different forms of communication. Although sharks are loners, they have the intelligence to communicate.Images of the most common types of shark tails. Tails are important part of shark anatomy which help them to achieve fast swimming speeds.