Agriculture
Silk’s superpowers
Middle school science adventures
Keeping Bugs Away from Food
Amphibians
Frogs and Toads
Toads
Newts
Animals
G-Tunes with a Message
Baboons Listen for Who's Tops
Vampire Bats on the Run
Behavior
Baby Talk
Supersonic Splash
Listen and Learn
Birds
Parrots
Albatrosses
Birds We Eat
Chemistry and Materials
The hungry blob at the edge of the universe
Unscrambling a Gem of a Mystery
Hitting the redo button on evolution
Computers
The Earth-bound asteroid scientists saw coming
Electronic Paper Turns a Page
Games with a Purpose
Dinosaurs and Fossils
Meet your mysterious relative
Dinosaurs Grow Up
Dino-Dining Dinosaurs
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
Results of GSAT are in schools this week
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Earth
Polar Ice Feels the Heat
Pollution at the ends of the Earth
Vitamin D-licious Mushrooms
Environment
Little Bits of Trouble
Swimming with Sharks and Stingrays
Missing Tigers in India
Finding the Past
Stonehenge Settlement
Unearthing Ancient Astronomy
A Long Trek to Asia
Fish
Skates and Rays
Hammerhead Sharks
Basking Sharks
Food and Nutrition
The Color of Health
Recipe for Health
Turning to Sweets, Fats to Calm the Brain
GSAT English Rules
Capitalization Rules
Whoever vs. Whomever
Order of Adjectives
GSAT Exam Preparation Jamaica
Ministry of Education Announces 82 GSAT Scholarships for 2010
2014 GSAT Results for Jamaican Kids
March 21-22, 2013: Over 43,000 students will take the GSAT Exam
GSAT Exams Jamaica Scholarships
Access denied - Disabled boy aces GSAT
42,000 students will sit for the GSAT Exam in two weeks
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Mathematics
A Sweet Advance in Candy Packing
Deep-space dancers
Math is a real brain bender
Human Body
Don't Eat That Sandwich!
Hey batter, wake up!
Gut Germs to the Rescue
Invertebrates
Krill
Shrimps
Worms
Mammals
Jaguars
Gray Whale
African Ostrich
Parents
Raise a Lifelong Reader by Reading Aloud
Expert report highlights the importance to parents of reading to children!
How children learn
Physics
Black Hole Journey
One ring around them all
Powering Ball Lightning
Plants
Fastest Plant on Earth
Fast-flying fungal spores
White fuzzy mold not as friendly as it looks
Reptiles
Sea Turtles
Asp
Iguanas
Space and Astronomy
Planet Hunters Nab Three More
Asteroid Moons
Super Star Cluster in the Neighborhood
Technology and Engineering
Weaving with Light
Riding Sunlight
Shape Shifting
The Parts of Speech
Adjectives and Adverbs
Countable and Uncountable Nouns
What is a Noun
Transportation
Are Propellers Fin-ished?
Middle school science adventures
Robots on a Rocky Road
Weather
In Antarctica watch the heat (and your step)
Where rivers run uphill
Warmest Year on Record
Add your Article

Sea Anemones

Named after a terrestrial flower, the anemone, sea anemones form a group of water-dwelling, filter feeding animals of the order Actinaria. As a cnidarian, the sea anemone is closely related to coral and jellyfish. Other close relations to the sea anemone are the solitary, tube-dwelling anemones and the hydras. Sea flowers: An anemone is basically the typical polyp: a small sac, attached to the bottom by an adhesive foot, with a column shaped body ending in an oral disc. The mouth is in the middle of the oral disc, surrounded by tentacles armed with many cnidocytes, which are unique cells that function as a defense and as a means to capture prey. Toxic hairs: Cnydocytes contain cnidae, capsule-like organelles capable of everting, giving phylum Cnidaria its name . The cnidae that sting are called nematocysts. Each nematocyst contains a small vesicle filled with toxins— actinoporins— an inner filament and an external sensory hair. When the hair is touched, it mechanically triggers the cell explosion, that fires a harpoon-like structure which attaches to organisms that trigger it, and injects a dose of poison in the flesh of the aggressor or prey. Sticky, but not toxic to all: This gives the anenome its characteristic sticky feeling. Interestingly the clownfish is immune to an anenome's sting. The poison is actually a mix of toxins, including neurotoxins, which serve to paralyze and capture the prey, which is then moved by the tentacles to the mouth/anus for digestion inside the gastrovascular cavity. Actinoporins have been reported as highly toxic to fish and crustaceans, which may be the natural prey of sea anemones. In addition to their role in predation, it has been suggested that actinoporins could act, when released in water, as efficient repellents against potential predators. Internal anatomy: The internal anatomy of anemones is very simple. There is a gastrovascular cavity (which functions as a stomach) with a single opening to the outside which fuctions as both a mouth and an anus: waste and undigested matter is excreted through the mouth/anus. A primitive nervous system, without centralization, coordinates the processes involved in maintaining homeostasis as well as biochemical and physical responses to various stimuli. Anemones range in size from less than 1¼ cm (½ in) to nearly 2 m (6 ft) in diameter. They can have a range of 10 tentacles to hundreds. Parasite: A few anemones are parasitic to marine organisms. Anemones tend to stay in the same spot unless they are unhappy with that location, or a predator is attacking them. In the case of an attack, anemones can uproot themselves and swim away to a new location, using flexing motions. Attachment: The sea anemone has a foot which in most species attaches itself to rocks or anchors in the sand. Some species attach to kelp and others are free-swimming. Although not plants and therefore incapable of photosynthesis themselves, many sea anemones form an important symbiosis with certain single-celled green algae species which reside in the animals' gastrodermal cells. These algae may be either zooxanthellae, zoochlorellae or both. The sea anemone benefits from the products of the algae's photosynthesis, namely oxygen and food in the form of glycerol, glucose and alanine; the algae in turn are assured a reliable exposure to sunlight, which the anemones actively maintain. The preponderance of species inhabit tropical reefs, although there are species adapted to relatively cold waters, intertidal reefs, and sand/kelp environments. Symbiotic relationships: Some sea anemones form symbiotic relationships with crabs or with anemone fish, also known as clownfish. In the former situation, anemones will either attach or be attached to the shell of a hermit crab (by the crab's own volition), providing additional protection for the crab and allowing the anemone to eat scraps when the crab feeds. A similar relationship can be formed between a sea anemone and a clownfish. The clownfish presses itself into the anemone, living comfortably within the stinging tentacles. This is possible because of a protective mucus that covers the clownfish. It is not yet fully understood whether the protective mucus impedes the nemtocysts from penetrating the flesh of the clownfish or if the mucus supresses nematocysts from firing. The clownfish benefits from this symbiotic relationship because it is protected by the anemone and in turn the anemone benefits because it gets food scraps from the clownfish. Muscles and nerves: The muscles and nerves in anenomes are much simpler than those of other animals. Cells in the outer layer (epidermis) and the inner layer (gastrodermis) have microfilaments grouped together into contractile fibers. These are not true muscles because they are not freely suspended in the body cavity as they are in more developed animals. Since the anemone lacks a skeleton, the contractile cells pull against the gastrovascular cavity, which acts as a hydrostatic skeleton. The stability for this hydrostatic skeleton is caused by the anemone shutting its mouth closed, which keeps the gastrovascular cavity at a constant volume, making it more rigid. Fossils: Most Actinaria do not form hard parts that can be recognized as fossils but a few fossils do exist; Mackenzia, from the Middle Cambrian Burgess Shale of Canada, is the oldest fossil identified as a sea anemone. Unlike other cnidarians, anemones (and other anthozoans) entirely lack the free-swimming medusa stage of the life cycle: the polyp produces eggs and sperm, and the fertilized egg develops into a planula that develops directly into another polyp. Separate sexes: The sexes in sea anemones are separate. Both sexual and asexual reproduction may occur. In sexual reproduction males release sperm which stimulates females to release eggs, and fertilization occurs. The eggs or sperm are ejected through the mouth. The fertilized egg develops into a planula, which finally settles down somewhere and grows into a single anemone. They can also reproduce asexually by budding, binary fission, which involves pulling apart into two halves, and pedal laceration, in which small pieces of the pedal disc break off and regenerate into small anemones. Laceration is a process of fragmentation of the basal disk, or by pulling itself into two parts.

Sea Anemones
Sea Anemones








Designed and Powered by HBJamaica.com™