Shark, in the context of marine biology, refers to a group of cartilaginous fish belonging to the class Chondrichthyes. They are characterized by their streamlined bodies, sharp teeth, and powerful swimming abilities.

With over 500 known species, sharks are an important part of the ocean ecosystem. They play a crucial role in maintaining the balance of marine food chains by regulating the population of smaller fish and marine organisms.

Sharks have a unique respiratory system that allows them to extract oxygen from water using gills. These gills enable them to efficiently extract dissolved oxygen from the surrounding water, enabling them to survive and thrive in various marine environments.

Sharks have a reputation for their predatory nature, mainly due to species such as the great white shark and tiger shark. However, it is important to note that not all sharks are aggressive towards humans. In fact, most shark species are harmless and pose little threat to humans.

Sharks have evolved over millions of years, adapting to various habitats and developing specialized features. Their unique anatomy, including their sleek bodies and rows of replaceable teeth, enables them to excel as efficient hunters in the marine environment.

Human activities, such as overfishing and habitat destruction, pose significant threats to shark populations worldwide. Conservation efforts are essential to protect these fascinating creatures and maintain the integrity of marine ecosystems.