معرفی دنـــــیای زیر آب

[Matin H-d 18145]

یکی از زیباترین اماکن جهان که کمتر به آن پرداخته شده است، دنیای زیر آب است. زیبایی‌های این جهان چنان شگفت‌انگیز هستند که همه را متعجب و متحیر می‌کند.

در همین راستا در هر پست به معرفی مختصر و مفید در هر گونه جانوری یا گیاهی میپردازیم .:girl_yes2:

 

** منبع nationalgeographic

[Matin H-d 18145]

Invertebrate

Diet:

Carnivore

Average life span in the wild:

Up to 35 years

Size:

4.7 to 9.4 in (12 to 24 cm)

Weight:

Up to 11 lbs (5 kg)

Did you know?

Sea stars have no brains and no blood. Their nervous system is spread through their arms and their “blood” is actually filtered sea water.

Size relative to a tea cup:

 

[Matin H-d 18145]

Marine scientists have undertaken the difficult task of replacing the beloved starfish’s common name with sea star because, well, the starfish is not a fish. It’s an echinoderm, closely related to sea urchins and sand dollars.

There are some 2,000 species of sea star living in all the world’s oceans, from tropical habitats to the cold seafloor. The five-arm varieties are the most common, hence their name, but species with 10, 20, and even 40 arms exist.

They have bony, calcified skin, which protects them from most predators, and many wear striking colors that camouflage them or scare off potential attackers. Purely marine animals, there are no freshwater sea stars, and only a few live in brackish water.Beyond their distinctive shape, sea stars are famous for their ability to regenerate limbs, and in some cases, entire bodies.

 

They accomplish this by housing most or all of their vital organs in their arms. Some require the central body to be intact to regenerate, but a few species can grow an entirely new sea star just from a portion of a severed limb.Most sea stars also have the remarkable ability to consume prey outside their bodies.

 

Using tiny, suction-cupped tube feet, they pry open clams or oysters, and their sack-like cardiac stomach emerges from their mouth and oozes inside the shell. The stomach then envelops the prey to digest it, and finally withdraws back into the body.

 

 

Sea stars are purely marine animals, even using sea water instead of blood to pump nutrients throughout their bodies.

[Matin H-d 18145]

Type:

Invertebrate

Diet:

Omnivore

Average life span in the wild:

50 years

Size:

Up to 3.25 ft (1 m) long

Did you know?

The largest lobster recorded was caught off the coast of Nova Scotia, Canada, and weighed 44.4 lbs (20.14 kg); it was between 3 and 4 ft (0.9 to 1.2 m) long. Scientists think it was at least 100 years old.

Size relative to a tea cup:

 

 

To many, it may seem that the lobster’s most natural habitat is on a large, oval plate between a cup of drawn butter and a lemon wedge.

In fact, only a few of the hundreds of types of lobster are caught commercially. But those few species are some of the most heavily harvested creatures in the sea, and generate a multi-billion-dollar industry, with more than 200,000 tons (181,436 metric tons) of annual global catch.The lobsters that most people know from their dinner plates are the American and European clawed lobsters Homarus americanus and Homarus gammarus. These are cold water species that live on either sides of the northern Atlantic Ocean. There are also tropical lobsters that are widely consumed, but these are generally clawless varieties called spiny and slipper lobsters.Lobsters are ten-legged crustaceans closely related to shrimp and crabs. These benthic, or bottom-dwelling, creatures are found in all of the world’s oceans, as well as brackish environments and even freshwater. They have poor eyesight but highly developed senses of taste and smell. They feed primarily on fish and mollusks, but will consume algae and other plant life and even other lobsters.Female lobsters carry their eggs under their abdomens for up to a year before releasing them as larvae into the water. The larvae go through several stages in the water column before settling on the bottom, where they spend the rest of their lives. They generally prefer to live in self-dug burrows, in rocky crevices, or hidden among sea grasses. Lobsters must shed their shells in order to grow, and some species can live to be 50 years old or more, growing continually throughout their lives.Lobsters have not always been considered chic eats. In 17th- and 18th-century America, they were so abundant in the northeast that they were often used as fertilizer. Laws were even passed forbidding people to feed servants lobster more than twice a week. However, improvements in U.S. transportation infrastructure in the 19th and 20th century brought fresh lobster to distant urban areas, and its reputation as a delicacy grew.Populations of commercially important lobster species are thought to be declining, and overfishing, particularly of clawed lobsters in Europe, is taking a toll. Additionally, pollution is causing shell rot and other illnesses in normally disease-resistant species.

Closely related to crabs and shrimp, this ten-legged crustacean has become a delicacy over time as overfishing of commercially important lobster species chips away at the global population.

 

[Matin H-d 18145]

Type:

Invertebrate

Diet:

Omnivore

Average life span in the wild:

5 to 10 years

Size:

0.75 in to 6.5 ft (2 to 200 cm)

Size relative to a 6-ft (2-m) man:

 

 

Sea cucumbers are echinoderms—like starfish and sea urchins. There are some 1,250 known species, and many of these animals are indeed shaped like soft-bodied cucumbers. All sea cucumbers are ocean dwellers, though some inhabit the shallows and others live in the deep ocean. They live on or near the ocean floor—sometimes partially buried beneath it.

Sea cucumbers feed on tiny particles like algae, minute aquatic animals, or waste materials, which they gather in with 8 to 30 tube feet that look like tentacles surrounding their mouths. The animals break down these particles into even smaller pieces, which become fodder for bacteria, and thus recycle them back into the ocean ecosystem. Earthworms perform a similar function in terrestrial ecosystems.

Sea cucumbers, particularly eggs and young larvae, are prey for fish and other marine animals. They are also enjoyed by humans, especially in Asia, and some species are farmed as delicacies.

When threatened, some sea cucumbers discharge sticky threads to ensnare their enemies. Others can mutilate their own bodies as a defense mechanism. They violently contract their muscles and jettison some of their internal organs out of their anus. The missing body parts are quickly regenerated.

Sea cucumbers can breed ***ually or a***ually. ***ual reproduction is more typical, but the process is not very intimate. The animals release both eggs and sperm into the water and fertilization occurs when they meet. There must be many individuals in a sea cucumber population for this reproductive method to be successful. Indeed, many parts of the deep ocean host large herds of these ancient animals, grazing on the microscopic bounty of marine waters.

 

 

All sea cucumbers are ocean-dwellers, though some inhabit the shallows and others live in the deep ocean

 

 

[Matin H-d 18145]

Kelp rockfish navigate a towering kelp forest near California's Bodega Bay. Kelp is one of the world's fastest-growing plants, with some species adding up to a foot (31 centimeters) per day.

 

[Matin H-d 18145]

 

The banded sea krait’s lethal venom packs a punch ten times more toxic than a rattlesnake’s, but fortunately these serpents are so meek that human bites are rare.

Kraits cruise the shallow, tropical waters of coral reefs and mangrove swamps. But, alone among the sea snakes, they are amphibious and able to spend up to ten days at a time on land. Sea kraits hit the beach to digest their food (mostly eels and fish), mate, and lay eggs.

[Matin H-d 18145]

Fast Facts

 

Type:Fish

Diet:Carnivore

Size:15 ft (4.6 m) to more than 20 ft (6 m)

Weight:5,000 lbs (2,268 kg) or more

Group name:School or shoal

Protection status:Endangered

Did you know?Great whites can detect one drop of blood in 25 gal (100 L) of water and can sense even tiny amounts of blood in the water up to 3 mi (5 km) away

 

.Size relative to a bus:

 

The legendary great white shark is far more fearsome in our imaginations than in reality. As scientific research on these elusive predators increases, their image as mindless killing machines is beginning to fade.Of the 100-plus annual shark attacks worldwide, fully one-third to one-half are attributable to great whites. However, most of these are not fatal, and new research finds that great whites, who are naturally curious, are "sample biting" then releasing their victims rather than preying on humans. It's not a terribly comforting distinction, but it does indicate that humans are not actually on the great white's menu.Great whites are the largest predatory fish on Earth. They grow to an average of 15 feet (4.6 meters) in length, though specimens exceeding 20 feet (6 meters) and weighing up to 5,000 pounds (2,268 kilograms) have been recorded.They have slate-gray upper bodies to blend in with the rocky coastal sea floor, but get their name from their universally white underbellies. They are streamlined, torpedo-shaped swimmers with powerful tails that can propel them through the water at speeds of up to 15 miles (24 kilometers) per hour. They can even leave the water completely, breaching like whales when attacking prey from underneath.Highly adapted predators, their mouths are lined with up to 300 serrated, triangular teeth arranged in several rows, and they have an exceptional sense of smell to detect prey. They even have organs that can sense the tiny electromagnetic fields generated by animals. Their main prey items include sea lions, seals, small toothed whales, and even sea turtles, and carrion.Found in cool, coastal waters throughout the world, there is no reliable data on the great white's population. However, scientists agree that their number are decreasing

precipitously due to overfishing and accidental catching in gill nets, among other factors, and they are listed as an endangered species.

 

Great whites are torpedo-shaped with powerful tails that can propel them through the water at up to 15 miles (24 kilometers) per hour.