Chambers In The Nautilus's Shell example essay topic

CHAMBERED NAUTILUS (NAUTILUS POMPILIUS) STEVEN HEGARTY CHAMBERED NAUTILUS L. KOCH MARINE SCIENCE 12/21/99 Hegarty 1 The chambered nautilus is a cephalopod, which also includes squid, octopus, and cuttlefish, which belongs to mollusca. There are several species of the nautilus, which include Allo nautilus scrobiculatus, Nautilus belauensis, Nautilus macromphalus, Nautilus pompilius, Nautilus repertus, and Nautilus stenomphalus. The nautilus is found in only a 15 degree band near the equator in the Pacific Ocean. (so est) The nautilus has been around for over 500 million years, and has changed at all. It was once one of the many different kinds of shelled cephalopods, but now is the only one left. (all resources) The nautilus ranges from 500 to 1000 ft. under the ocean along reef slopes and walls.

Nautiluses are scavengers feeding mostly on crustaceans. Nautiluses live so deep because if they deeper than 800 m there shells will implode and at 500 m there shells will flood. Nautiluses prefer water temperatures of around 21 degrees C, that is another reason they live so deep. (o zeman) At night the nautiluses rise to the depth of 100 to 200 ft. to eat, though they are not nocturnal. This is the only time scientists have been able to study the nautilus in it's natural habitat, and yet they still have to trap them to observe them. The scientists use a trap, made out of either mesh or plastic, with a 12 hole in it. The trap is baited with fish or even sometimes even chicken.

The scientists let the net set for the night and pull it up the next morning to retrieve the catch. Due to the fact that the chambers in the nautilus's shell are filled with air, the animal is unharmed when brought to the surface. (underwater) Hegarty 1 Nautiluses spend a lot of their time roaming the bottom. They propel themselves with a flexible tube like jet This jet can be directed at any angle to steer themselves around the reef. (underwater) Above its jet the nautilus has a beaked mouth, like that of other cephalopods. Around the mouth there are 80 to 100 very sticky tentacles, which enables the nautilus to pull food closer to it's mouth, such as the molted skeleton of spiny or slipper lobster. The entire body of this creature is located in the first chamber of the shell. When threatened the nautilus covers it's entire body with a tough flexible covering. (underwater).

The nautilus needs this kind of protection from creatures like triggerfish, sea turtles, and sharks. (Mrs. Koch) The shell of the nautilus is unique in which the inside is riddled with chambers (38 chambers). The nautilus uses these chambers to move itself up and down in the water column. Even though the shell resembles that of a snail, the nautilus is more closely related to the cephalopods. This shape helps the nautilus from being crushed under the enormous pressure. (Mrs. Koch) Nautiluses can grow to as much as 12 in diameter and weigh 2 lbs.

The nautilus doesn t reach sexual maturity until 15 to 20 years of age. Unlike other cephalopods, the nautilus lives after reproduction. Scientists re not sure as to how old nautiluses get to be. The nautiluses lay 1 + long eggs, which hatch into babies an 1 in diameter. (Mrs. Koch) The shells of the nautilus have long been prized by humans for their natural beauty. In the Tan on Strait of the Philippines the hole nautilus population has been wiped out because of over fishing and the fact it takes so long for nautiluses to reach sexual maturity.

(Mrs. Koch) [Online] Chambered Nautilus Research Available: web (99 dec 17) [Classroom] Lisa Koch Available: (99 dec 2) [Online] Nautiloidea Available: web (99 nov 30) [Online] Kevin Davidson Underwater Photo Tips Available: web (99 dec 12) [Online] Cephalopods Of The Coral Sea Available: web (99 dec 12).