Animals of the Sea
Marine animals are divided into three groups: zooplankton (those that float), nekton (those that actively swim) and benthos (those that live on or in the ocean bottom).
Marine animals are divided into three groups: zooplankton, nekton, and benthos.
Zooplankton are drifting animals and are usually small, however, they can grow to fairly large size. For example, the jellyfish and the Portuguese man-of-war are examples of larger types of zooplankton which are unable to propel themselves effectively and are therefore at the mercy of either wind or current. The zooplankton population also includes some temporary members such as fish eggs or larval forms of organisms which may grow up and leave the planktonic community to join the nekton or benthos.
Nekton are the free swimmers and probably the largest portion of familiar animals found in the ocean belong to this class. Common fishes, the octopus, whales, eels and squid are all examples of nekton. The nekton category includes a number of very diverse creatures. The whale, dolphin and porpoise are certainly very different from codfish or trout because whales represent sea mammals whereas cod are true fishes.
The third type of sea animal spends its entire life on or in the ocean bottom. This group of marine animals is called the benthos. It includes lobsters, starfish, various worms, snails, oysters and many more. Some of these creatures, such as lobsters and snails, may be able to move about on the bottom but their lifestyle is so bound up with the ocean floor that they are unable to survive away from this environment.
Marine animals are divided into three groups: zooplankton (those that float), nekton (those that actively swim) and benthos (those that live on or in the ocean bottom).
Marine animals are divided into three groups: zooplankton, nekton, and benthos.
Zooplankton are drifting animals and are usually small, however, they can grow to fairly large size. For example, the jellyfish and the Portuguese man-of-war are examples of larger types of zooplankton which are unable to propel themselves effectively and are therefore at the mercy of either wind or current. The zooplankton population also includes some temporary members such as fish eggs or larval forms of organisms which may grow up and leave the planktonic community to join the nekton or benthos.
Nekton are the free swimmers and probably the largest portion of familiar animals found in the ocean belong to this class. Common fishes, the octopus, whales, eels and squid are all examples of nekton. The nekton category includes a number of very diverse creatures. The whale, dolphin and porpoise are certainly very different from codfish or trout because whales represent sea mammals whereas cod are true fishes.
The third type of sea animal spends its entire life on or in the ocean bottom. This group of marine animals is called the benthos. It includes lobsters, starfish, various worms, snails, oysters and many more. Some of these creatures, such as lobsters and snails, may be able to move about on the bottom but their lifestyle is so bound up with the ocean floor that they are unable to survive away from this environment.