Agriculture
Making the most of a meal
Where Have All the Bees Gone?
Getting the dirt on carbon
Amphibians
Bullfrogs
Salamanders
Toads
Animals
A Seabird's Endless Summer
Little Beetle, Big Horns
Roach Love Songs
Behavior
Eating Troubles
Ear pain, weight gain
Fighting fat with fat
Birds
Chicken
Penguins
Turkeys
Chemistry and Materials
A Spider's Silky Strength
These gems make their own way
Cold, colder and coldest ice
Computers
Middle school science adventures
Fingerprint Evidence
Toxic Dirt + Avian Flu = Science Fair Success
Dinosaurs and Fossils
Dino Flesh from Fossil Bone
Mammals in the Shadow of Dinosaurs
A Really Big (but Extinct) Rodent
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
Vitamin D-licious Mushrooms
Shrinking Glaciers
Recipe for a Hurricane
Environment
Acid Snails
Shrimpy Invaders
Groundwater and the Water Cycle
Finding the Past
Digging Up Stone Age Art
A Long Haul
Sahara Cemetery
Fish
Saltwater Fish
Marlin
Bull Sharks
Food and Nutrition
Making good, brown fat
Chew for Health
A Pepper Part that Burns Fat
GSAT English Rules
Capitalization Rules
Subject and Verb Agreement
Finding Subjects and Verbs
GSAT Exam Preparation Jamaica
42,000 students will sit for the GSAT Exam in two weeks
GSAT stars reap scholarship glory
GSAT Practice Papers | GSAT Mathematics | Maths
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
How a Venus Flytrap Snaps Shut
GSAT Mathematics Quiz, Teaching Math, teaching anxiety
42,000 students will sit for the GSAT Exam in two weeks
Human Body
Taste Messenger
What the appendix is good for
Flu Patrol
Invertebrates
Lobsters
Camel Spiders
Crabs
Mammals
Seal
Asian Elephants
Numbats
Parents
How children learn
Choosing a Preschool: What to Consider
Children and Media
Physics
Extra Strings for New Sounds
Einstein's Skateboard
Echoes of a Stretched Egg
Plants
Farms sprout in cities
Getting the dirt on carbon
Nature's Alphabet
Reptiles
Alligators
Snakes
Snapping Turtles
Space and Astronomy
Super Star Cluster in the Neighborhood
Killers from Outer Space
A Smashing Display
Technology and Engineering
Reach for the Sky
Sugar Power for Cell Phones
Drawing Energy out of Wastewater
The Parts of Speech
Pronouns
What is a Noun
What is a Preposition?
Transportation
Seen on the Science Fair Scene
Robots on a Rocky Road
Where rivers run uphill
Weather
Weekend Weather Really Is Different
Arctic Melt
Recipe for a Hurricane
Add your Article

Oysters

The name oyster is used for a number of different groups of mollusks which grow for the most part in marine or brackish water. The shell, usually highly calcified, surrounds a soft body. Gills filter plankton from the water, and strong adductor muscles are used to hold the shell closed. They are highly prized as food, both raw and cooked. Pollutant filters: Oysters are filter-feeders that draw water in over their gills through the beating of cilia. Suspended food plankton and particles are trapped in the mucus of the gills and transported to the mouth, where they are eaten, digested and expelled as feces or pseudofeces. Feeding activity is greatest in oysters when water temperatures are above 50F (10C). Healthy oysters consume algae and other water-borne nutrients, each one filtering up to five litres of water per hour. Scientists believe that the Chesapeake Bay's once-flourishing oyster populations historically filtered the estuary's entire water volume of excess nutrients every three or four days. Today that process would take almost a year, and sediment, nutrients, and algae can cause problems in local waters. Oysters filter these pollutants, and either eat them or shape them into small packets that are deposited on the bottom where they are harmless. Colorless blood: Oysters breathe much like fish, using both gills and mantle. The mantle is lined with many small, thin-walled blood vessels which extract oxygen from the water and expel carbon dioxide. A small, three-chambered heart, lying under the abductor muscle, pumps colorless blood, with its supply of oxygen, to all parts of the body. At the same time a pair of kidneys located on the underside of the muscle purify the blood of any waste products it has collected. Pearls of foreigners: An oyster produces a pearl when foreign material becomes trapped inside the shell. The oyster responds to the irritation by producing nacre, a combination of calcium and protein. The nacre coats the foreign material and over time produces a pearl. Dinner plate sized pearls: All types of oysters (and, indeed, many other shelled mollusks) can secrete pearls, but those from edible oysters have no market value. The Pearl Oysters come from a different family, the Pteriidae (Feathered Oysters). Both cultured pearls and natural pearls are obtained from these oysters, though some other mollusks, for example freshwater mussels, also yield pearls of commercial value. The largest pearl-bearing oyster type is the Pinctada maxima, which is roughly the size of a dinner plate. Not all individual oysters produce pearls. In fact, in a haul of three tons of oysters, only around three or four oysters produce perfect pearls. Grit caused: These oysters produce pearls by covering an invading piece of grit with nacre. Over the years, the grit is covered with enough nacre to form what we know as a pearl. There are many different types and colours and shapes of pearl, but this depends on the pigment of the nacre and the shape of the piece of grit being covered over. The perfect pearl: Pearls can also be cultivated by pearl farmers placing a single piece of grit, usually a piece of polished mussel shell, inside the oyster. In three to six years, the oyster will produce a perfect pearl. These pearls are not as valuable as natural pearls, but look exactly the same. In fact since the beginning of the 20th century when several researchers discovered how to produce artificial pearls, the cultured pearl market has far outgrown the natural pearl market. Natural pearls have become scarcer and scarcer and a necklace with only natural pearls can easily costs in the hundreds of thousands of (US) dollars. There is no way of telling male oysters from females by examining their shells. While oysters have separate sexes, they may change sex one or more times during their life span. The gonads, organs responsible for producing both eggs and sperm, surround the digestive organs and are made up of sex cells, branching tubules and connective tissue.

Oysters
Oysters








Designed and Powered by HBJamaica.com™