Agriculture
Keeping Bugs Away from Food
Making the most of a meal
Springing forward
Amphibians
Salamanders
Salamanders and Newts
Toads
Animals
Assembling the Tree of Life
The History of Meow
New Mammals
Behavior
Newly named fish crawls and hops
Training Your Brain to Feel Less Pain
Puberty gone wild
Birds
Owls
Kiwis
Hawks
Chemistry and Materials
The hottest soup in New York
Undercover Detectives
Watching out for vultures
Computers
Computers with Attitude
A Classroom of the Mind
Nonstop Robot
Dinosaurs and Fossils
Digging for Ancient DNA
Hunting by Sucking, Long Ago
Teeny Skull Reveals Ancient Ancestor
E Learning Jamaica
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Results of GSAT are in schools this week
2014 GSAT Results for Jamaican Kids
Earth
Meteorites may have sparked life on Earth
A Grim Future for Some Killer Whales
Shrinking Glaciers
Environment
Eating Up Foul Sewage Smells
Cactus Goo for Clean Water
Shrinking Fish
Finding the Past
Stone Age Sole Survivors
Meet your mysterious relative
Decoding a Beverage Jar
Fish
Mako Sharks
Perches
Skates and Rays
Food and Nutrition
Healing Honey
Chew for Health
Building a Food Pyramid
GSAT English Rules
Pronouns
Problems with Prepositions
Who vs. Whom
GSAT Exam Preparation Jamaica
Tarrant High overcoming the odds
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Scholarship
GSAT Exams Jamaica Scholarships
Results of GSAT are in schools this week
GSAT Scholarship
42,000 students will sit for the GSAT Exam in two weeks
GSAT Mathematics
GSAT Mathematics Quiz, Teaching Math, teaching anxiety
Losing with Heads or Tails
Setting a Prime Number Record
Human Body
Heavy Sleep
Dreaming makes perfect
Opening a Channel for Tasting Salt
Invertebrates
Termites
Flatworms
Giant Squid
Mammals
Giraffes
Wombats
Platypus
Parents
Children and Media
The Surprising Meaning and Benefits of Nursery Rhymes
What Not to Say to Emerging Readers
Physics
Road Bumps
Spin, Splat, and Scramble
Black Hole Journey
Plants
Fungus Hunt
Tracking the Sun Improves Plant Pollen
Stalking Plants by Scent
Reptiles
Sea Turtles
Chameleons
Gila Monsters
Space and Astronomy
Planets on the Edge
Saturn's Spongy Moon
An Earthlike Planet
Technology and Engineering
Squeezing Oil from Old Wells
Spinach Power for Solar Cells
Riding Sunlight
The Parts of Speech
Countable and Uncountable Nouns
Adjectives and Adverbs
Problems with Prepositions
Transportation
Where rivers run uphill
Middle school science adventures
Troubles with Hubble
Weather
Earth's Poles in Peril
The solar system's biggest junkyard
Catching Some Rays
Add your Article

Nautiluses

Nautilus (from Greek nautilos, 'sailor') is the common name of any marine creatures of the cephalopod family Nautilidae, the sole family of the suborder Nautilina. It comprises 6 very similar species in 2 genera, the type of which is the genus Nautilus. The name chambered nautilus is also used for any species of the Nautilidae, though it more specifically refers to the species Nautilus pompilius suluensis. Living fossils: Having survived relatively unchanged during millions of years, nautiluses represent the only living members of the subclass Nautiloidea, and are often considered to be "living fossils". No suckers, many tentactles, nine teeth: The nautilus is similar in general form to other cephalopods, with a prominent head and tentacles. Nautiluses typically have more tentacles than other cephalpods, up to ninety. These tentacles are arranged into two circles and, unlike the tentacles of other cephalopods, they have no suckers, are undifferentiated and retractable. The radula is wide and distinctively has nine teeth. There are two pairs of gills. The largest adults can reach 220 mm in diameter. Pearly insides: Nautiluses are the sole cephalopods whose bony structure of the body is externalized as a shell. The animal can withdraw completely into its shell, closing the opening with a leathery hood formed from two specially folded tentacles. The shell is coiled, calcareous, mother-of-pearl-lined and pressure resistant (imploding at a depth of about 800 m). The nautilus shell is composed of 2 layers: the outer layer is a matte white, while the inner layer is a striking white with iridescence. The innermost portion of the shell is pearlescent, blue-gray. The osmena pearl, contrarily to its name, is not a pearl, but a jewelry product derived from this part of the shell. Chambers in the shell: The shell is internally divided into chambers, the chambered section being called the phragmocone. The phragmocone is divided into camerae by septa, all of which are pierced in the middle by a duct, the siphuncle. As the nautilus matures its body moves forward, sealing the camerae behind it with a new septum. The last fully open chamber, also the largest one, is used as the living chamber. The number of camerae increases from around four at the moment of hatching to thirty or more in adults. Cryptic coloring: The shell coloration also keeps the animal cryptic in the water. When seen from the top, the shell is darker in color and marked with irregular stripes, which makes it blend into the darkness of the water below. On the contrary, the underside is almost completely white, making the animal indistinguishable from brighter waters near the ocean surface. This mode of camouflage is named countershading. One of the finest natural logarithmic spiral: The nautilus shell presents one of the finest natural examples of a logarithmic spiral. (It is sometimes incorrectly claimed to be a golden spiral as well.) Jet propulsion: In order to swim, the nautilus draws water into and out of the living chamber with the hyponome, which makes use of jet propulsion. When water is inside the chamber, the siphuncle extracts salt from it and diffuses it into the blood. When water is pumped out, the animal adjusts it buoyancy with the gas contained in the chamber. Buoyancy can be controlled by the osmotical pumping of gas and fluid into or from the camerae along the siphuncles. The control of buoyancy in this manner limits the nautilus; they cannot operate under extreme hydrostatic pressures. The animal can also crawl on land or on the seabed. In the wild nautiluses usually inhabit depths of about 600-800 m, rising to around 200 m at night for feeding, mating and egg laying. Tentacle capture: Nautiluses are predators and feed mainly on shrimps, small fish and crustaceans, which are captured by the tentacles. Unlike other cephalopods, they do not have good vision; their eye structure is highly developed but lacks a solid lens. They have a simple "pinhole" lens through which water can pass. Instead of vision, the animal is thought to use olfaction as the primary sensory means during foraging, locating or identifying sexual partner. 12 month development: Nautiluses are sexually dimorphic and reproduce by laying eggs. Attached to rocks in shallow waters, the eggs take twelve months to develop before hatching out at around 30 mm long. The lifespan of nautiluses is about 20 years, which is exceptionally long for a cephalopod.

Nautiluses
Nautiluses








Designed and Powered by HBJamaica.com™