Box Jellyfish (Chironex fleckeri)

Hi , for this blog I´m excited to do because is the most dangerous Jellyfish in the world.

Chironex fleckeri, commonly known as the sea wasp, is a species of deadly venomous box jellyfish found in coastal waters from northern Australia and New Guinea north to the Philippines and Vietnam. It has been described as "the most lethal jellyfish in the world", with at least 63 known deaths in Australia from 1884 to 1996.

Notorious for its sting, C. fleckeri has tentacles up to 3 m (10 ft) long covered with millions of cnidocytes which, on contact, release microscopic darts delivering an extremely powerful venom. Being stung commonly results in excruciating pain, and if the sting area is significant, an untreated victim may die in two to five minutes. The amount of venom in one animal is said to be enough to kill 60 adult humans, although most stings are mild and do not require hospitalization.

When the jellyfish are swimming, the tentacles contract so they are about 15 cm long and about 5 mm in diameter; when they are hunting, the tentacles are thinner and extend to about 3 m long. The tentacles are covered with a high concentration of stinging cells called cnidocytes, which are activated by pressure and a chemical trigger; they react to proteinous chemicals. Box jellyfish are day hunters; at night they are seen resting on the ocean floor.

In common with other box jellyfish, C. fleckeri has four eye-clusters with 24 eyes. Some of these eyes seem capable of forming images, but whether they exhibit any object recognition or object tracking is debated; it is also unknown how they process information from their sense of touch and eye-like light-detecting structures due to their lack of a central nervous system. During a series of tests by marine biologists including Australian jellyfish expert Jamie Seymour, a single jellyfish was put in a tank. Then, two white poles were lowered into the tank. The creature appeared unable to see them and swam straight into them, thus knocking them over. Then, similar black poles were placed into the tank. This time, the jellyfish seemed aware of them, and swam around them in a figure-eight. Finally, to see if the specimen could see colour, a single red pole was stood in the tank. When the jellyfish apparently became aware of the object in its tank, it was seemingly repelled by it and remained at the far edge of the tank.[citation needed] Following these experiments, the Australian researchers put forward the idea of red safety nets for beaches (these nets are usually used to keep the jellyfish away, but many still get through its mesh). The test was repeated, with similar results, on Irukandji jellyfish, another toxic species of box jelly.

Chironex fleckeri lives on a diet of prawns and small fish, and are prey to turtles, whose thick skin is impenetrable to the cnidocytes of the jellyfish.

Irukandji Jellyfish (Carukia barnesi)

Hi , cmon you know for what i´m here so finish this early.

Irukandji jellyfish are a type of deadly venomous box jellyfish. With an adult size of roughly a cubic centimetre (1 cm3), they are both one of the smallest and most venomous jellyfish in the world. They inhabit the marine waters of Australia. They are able to fire their stingers into their victim, causing symptoms collectively known as Irukandji syndrome. There are about 16 known species of Irukandji, of which Carukia barnesi, Malo kingi, Malo maximus, Malo filipina and Malo bella are the best-known.

The symptoms of Irukandji syndrome were first documented by Hugo Flecker in 1952. They were named after the Irukandji people whose country stretches along the coastal strip north of Cairns, Queensland. The first of these jellyfish, Carukia barnesi, was identified in 1964 by Jack Barnes; to prove it was the cause of Irukandji syndrome, he captured the tiny jelly and allowed it to sting him while his son and a lifeguard observed the effects. He was lucky and only ended up mildly sick. Australian toxinologist Jamie Seymour made a documentary about the jellyfish called 'Killer Jellyfish'.

Irukandji jellyfish are very small, with a bell about 5 millimetres (0.20 in) to 25 millimetres (0.98 in) wide (or wider) and four long tentacles, which range in length from just a few centimeters up to 1 metre (3.3 ft) in length.

Malo Maximus mature irukandji typically have halo-like rings of tissue around their four tentacles. Apparently, it is the mature Irukanji that are highly venomous (in all species). Apparent Malo Maximus juveniles have been identified without the halo-rings, and without gonads, and have demonstrated far weaker toxicity in stinging researchers. The stingers (nematocysts) are in clumps, appearing as rings of small red dots around the bell and along the tentacles.

The Irukandji's small size and transparent body make it very difficult to see in the water.

Very little is known about the life cycle and venom of Irukandji jellyfish. This is partly because they are too small and fragile requiring special handling and containment.[citation needed] Their venom is very powerful; they are suspected of killing 5 tourists during a 3-month period in Australia. Researchers conjecture that the venom possesses such potency to enable it to quickly stun its prey, which consists of small and fast fish. Judging from statistics, it is believed that the Irukandji syndrome may be produced by several species of jellyfish, but only Carukia barnesi and Malo kingi have so far been proven to cause the condition.

Añadir leyenda

Portuguese Man o’ War (Physalia physalis)

Hi , I´m really tired of write this blogs but i need for pass the subject. So let´s go!

The Atlantic Portuguese man o' war (Physalia physalis), also known as the man-of-war, or floating terror, is a marine hydrozoan of the family Physaliidae found in the Atlantic Ocean, as well as the Indian and Pacific Oceans. Its venomous tentacles deliver a painful sting, which on extremely rare occasions has been fatal to humans. Despite its outward appearance, the Portuguese man o' war is not a jellyfish but a siphonophore, which, unlike jellyfish, is not a single multicellular organism, but a colonial organism made up of specialized individual animals (of the same species) called zooids or polyps. These polyps are attached to one another and physiologically integrated to the extent that they are unable to survive independently, and therefore have to work together and function like an individual animal.

The Indo-Pacific Portuguese man-of-war (P. utriculus), or blue bottle, is a related species with very similar appearance found throughout the Indian and Pacific Oceans.

The Atlantic Portuguese man o' war lives at the surface of the ocean. The gas-filled bladder, or pneumatophore, remains at the surface, while the remainder is submerged. As the Portuguese man o' war has no means of propulsion, it moves according to the winds, currents, and tides. Although it is most commonly found in the open ocean in tropical and subtropical regions, it has been found as far north as the Bay of Fundy, Cape Breton and the Hebrides.

Strong winds may drive them into bays or onto beaches. Often, finding a single Portuguese man o'war is followed by finding many others in the vicinity. They can sting while beached; the discovery of a man o' war washed up on a beach may lead to the closure of the beach.

The Portuguese man o' war is a carnivore. Using its venomous tentacles, a man o' war traps and paralyzes its prey while "reeling" it inwards to the digestive polyps . It typically feeds on small marine organisms, such as fish and plankton.

Portuguese man o' war in Tayrona National Natural Park, Colombia

The organism has few predators of its own; one example is the loggerhead turtle, which feeds on the Portuguese man o' war as a common part of its diet. The turtle's skin, including that of its tongue and throat, is too thick for the stings to penetrate.

The blue sea slug Glaucus atlanticus specializes in feeding on the Portuguese man o' war,as does the violet snail Janthina janthina.

The blanket octopus is immune to the venom of the Portuguese man o' war; young individuals carry broken man o' war tentacles, presumably for offensive and/or defensive purposes.

The ocean sunfish's primary diet consists of jellyfish, but it also consumes the Portuguese man o' war.

Lion’s Mane Jellyfish (Cyanea capillata)

Hi, aftere of all the work than i am doing today , here have another blog this turn is about the fourth most dangerous( Lion´s Mane Jellyfish) jellyfish in the world . So here we go!

The lion's mane jellyfish (Cyanea capillata), also known as the giant jellyfish or the hair jelly,is the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern Atlantic, and northern Pacific Oceans. It is common in the English Channel, Irish Sea, North Sea and in western Scandinavian waters south to Kattegat and Øresund. It may also drift in to the south-western part of the Baltic Sea (where it cannot breed due to the low salinity). Similar jellyfish – which may be the same species – are known to inhabit seas near Australia and New Zealand. The largest recorded specimen found, washed up on the shore of Massachusetts Bay in 1870, had a bell with a diameter of 2.3 metres (7 ft 6 in) and tentacles 37.0 m (121.4 ft) long. Lion's mane jellyfish have been observed below 42°N latitude for some time in the larger bays of the east coast of the United States.

The lion's mane jellyfish uses its stinging tentacles to capture, pull in and eat prey such as fish, sea creatures and smaller jellyfish.

Lion's mane jellyfish (Cyanea capillata) are named for their showy, trailing tentacles reminiscent of a lion's mane. They can vary greatly in size: although capable of attaining a bell diameter of over 2 metres (6 ft 7 in), those found in lower latitudes are much smaller than their far northern counterparts, with a bell about 50 centimetres (20 in) in diameter.

Size seems to dictate coloration: larger specimens are a vivid crimson to dark purple while smaller specimens grade to a lighter orange or tan, occasionally colorless.

The bell of the lion's mane jellyfish is scalloped into eight lobes (lappets), each lobe containing from 70 to 150 tentacles,arranged in four fairly distinct rows. Along the bell margin is a balance organ at each of the eight indentations between the lobes – the rhopalium – which helps the jellyfish orient itself. From the central mouth extend broad frilly oral arms with many stinging cells.

The long, thin tentacles which emanate from the bell's subumbrella have been characterised as “extremely sticky”; they also have stinging cells. The tentacles of larger specimens may trail as long as 30 m (100 ft) or more, with the tentacles of the longest known specimen measured at 37 m (120 ft) in length. This unusual length – longer than a blue whale – has earned it the status of one of the longest known animals in the world.

Sea nettle (Chrysaora)

Hi ,guys like I told you I´m going to talk about de fifth jellyfish of my last work the jellyfish: Sea nettle.

Chrysaora quinquecirrha (commonly named the Atlantic sea nettle or East Coast sea nettle) is a widely distributed species of jellyfish that inhabits tropical and subtropical parts of the Atlantic and Indo-Pacific. It is frequently seen along the East Coast of the United States, such as the Chesapeake Bay. It is smaller than the Pacific sea nettle, and has more variable coloration, but is typically pale, pinkish or yellowish, often with radiating more deeply colored stripes on the exumbrella, especially near the margin.

The sea nettle is radially symmetrical, marine, and carnivorous. Its mouth is located at the center of one end of the body, which opens to a gastrovascular cavity that is used for digestion. It has tentacles that surround the mouth to capture food. Nettles have no excretory or respiratory organs. Each sea nettle is either in a free-swimming stage or a polyp stage. The free-swimming stage, or medusa stage reproduces sexually, and the polyp stage reproduces asexually.

The Atlantic sea nettle is a bell-shaped invertebrate, usually semi-transparent and with small, white dots and reddish-brown stripes. Sea nettles without stripes have a bell that appears white or opaque. The nettle's sting is rated from "moderate" to "severe" and can be pernicious to smaller prey; it is not, however, potent enough to cause human death, except by allergic reaction. While the sting is not particularly harmful, it can cause moderate discomfort to any individual stung. The sting can be effectively neutralized by misting vinegar over the affected area. This keeps unfired nematocysts from firing and adding to the discomfort.

Stinging sea nettles are carnivorous. They generally feed on zooplankton, ctenophores, other jellies, and sometimes crustaceans. Nettles immobilize and obtain their prey using their stinging tentacles. After that, the prey is transported to the gastrovascular cavity where it is subsequently digested.

Nettles are also able to consume minnows, bay anchovy eggs, worms, and mosquito larvae.

Defense mechanisms:

Each nettle tentacle is coated with thousands of microscopic cnidocytes; in turn, every individual cnidocyte has a "trigger" (cnidocil) paired with a capsule containing a coiled stinging filament. Upon contact, the cnidocil will immediately initiate a process which ejects the venom-coated filament from its capsule and into the target. This will inject toxins capable of killing smaller prey or stunning perceived predators. On humans, this will most likely cause a nonlethal, but nevertheless painful rash typically persisting for about 20 minutes. Some earlier cases of nettle stings from the Philippines reportedly had more severe effects: one account describes a sting causing vascular insufficiency, and another mononeuritis.

Rather than toxic substances, some cnidocytes contain adhesion used to entangle or anchor its target. The defense mechanisms of the sea nettle reduces the amount of natural predators. The Atlantic Sea Nettle is prey to mainly sea turtles, ocean sunfish, and larger jellyfish.

ARIC SIGMAN´S THEORY

Hi guys, today I will express my opinion about the Aric Sigman´s theory.

In my opinion, I  agree with the idea that  parents have to show more authority  to their children. Nowadays, if you are walking in the streets or buying in the supermarket you can see some embarassing scenes,  how a child between 4-6 years old, is kicking and crying on the floor because he wants to obtain something that previously his  parents had already said no to.

 As well as that ,when you go out to have dinner you might see how a couple is dinning(or having dinner)  while their son is surfing the  Internet on the mobile or playing  video-games, and when his parents   tell him off (or reprimand him) he answers in an offensive way. 

I think that this kind of behaviour  occurs because  parents have not shown their authority during his childhood.

However,  I disagree (or don´t agree) with a point that  Aric Sigman  mentioned about physical contact. He suggested that  giving a slap to the child for reverting a wrong attitude  could be a good option. About this I only want to say that I am strongly against  using physical contact to educate a child.

To conclude, I think that  parents need to show more authority but, there are other ways to achieve  this goal than  using physical contact.


 

JELLYFISH

Hi again, today I´m going to talk about a really curious and strange animal,Jellyfish. I´m going to say the 5 most dangerous species of jellyfish in the world. I´m going to say it and puta n image of each one. And in the future blogs I´m going to talk about all the 5 more specific information. Enjoy!

5 Sea nettle (Chrysaora)

4 Lion’s Mane Jellyfish (Cyanea capillata)

 

 3 Portuguese Man o’ War (Physalia physalis)

 

2 Irukandji Jellyfish (Carukia barnesi)

1 Box Jellyfish (Chironex fleckeri)

CROCODILES

Hi guys,sorry for don´t do blogs at these weeks but I had a lot of exams and I can´t write a lot.. But don´t worry guys I´m here now, let´s do this! Today I´m going to talk about crocodiles{generally information but interesting] and maybe in the future i can do a blog about a specific crocodiles { if you want of course ]

Crocodiles (subfamily Crocodylinae) or true crocodiles are large aquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. Crocodylinae, all of whose members are considered true crocodiles, is classified as a biological subfamily. A broader sense of the term crocodile, Crocodylidae that includes Tomistoma, is not used in this article. The term crocodile here applies to only the species within the subfamily of Crocodylinae. The term is sometimes used even more loosely to include all extant members of the order Crocodilia, which includes the alligators and caimans (family Alligatoridae), the gharial and false gharial (family Gavialidae), and all other living and fossil Crocodylomorpha.

Crocodile size, morphology, behaviour and ecology differ somewhat among species. However, they have many similarities in these areas as well. All crocodiles are semiaquatic and tend to congregate in freshwater habitats such as rivers, lakes, wetlands and sometimes in brackish water and saltwater. They are carnivorous animals, feeding mostly on vertebrates such as fish, reptiles, birds and mammals, and sometimes on invertebrates such as molluscs and crustaceans, depending on species and age. All crocodiles are tropical species that, unlike alligators, are very sensitive to cold. They separated from other crocodilians during the Eocene epoch, about 55 million years ago.[3] Many species are at the risk of extinction, some being classified as critically endangered.

A crocodile’s physical traits allow it to be a successful predator. Its external morphology is a sign of its aquatic and predatory lifestyle. Its streamlined body enables it to swim swiftly; it also tucks its feet to the side while swimming, making it faster by decreasing water resistance. Crocodiles have webbed feet which, though not used to propel them through the water, allow them to make fast turns and sudden moves in the water or initiate swimming. Webbed feet are an advantage in shallower water where the animals sometimes move around by walking. Crocodiles have a palatal flap, a rigid tissue at the back of the mouth that blocks the entry of water. The palate has a special path from the nostril to the glottis that bypasses the mouth. The nostrils are closed during submergence.