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Practice English Speaking&Listening with: 6 Creatures That Live Forever

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From animals that never seem to age to those which can survive for years without food or

water, here are 6 creatures that can live forever.

Number 6 Ocean Quahog This edible clam species is native to the

North Atlantic Ocean and renowned for its longevity.

After about 25 years, a period in which the clam grows and reaches sexual maturity, scientists

have found that its antioxidant enzymes maintained stable level for more than 150 years.

In many animal cells, the molecules that contain oxygen react with the cell membranes, thus

damaging parts of the cell.

However, the membranes from the cells of ocean quahogs are unusually resistant to this type

of damage, which means that these creatures age at a negligible rate.

An ocean quahog was discovered by British researchers off the coast of Iceland, in 2006.

The clam died when they opened its shell, in order to examine it.

At the time, the researchers werent aware of the clams age, which carbon dating would

later place at 507 years old.

The discovery received a great deal of media attention and journalists from the Sunday

Times dubbed the clam Ming, as it was born during the Ming dynasty, towards the end of

the 1400s.

The researchers later named it Hafrun, which roughly translates asmystery of the ocean’.

Theres no way to tell how long the clam would have lived for if undisturbed from its

natural habitat.

Some have suggested that Ming might have been a rare example of biological immortality.

Number 5 Nematodes Nematodes are the roundworms which account

for about 80 per cent of all individual animals on our planet.

Theyre present in every part of the Earths lithosphere, including desserts, mountains

and oceanic trenches.

Theyre also found as parasites in the bodies of many vertebrates, including, in some cases,

humans.

According to nematologist Nathan CobbIf all the matter in the universe except the

nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied

spirits, we could then investigate it, we should find its mountains, hills, vales, rivers

and oceans represented by a film of nematodes’.

Such is the ubiquity of nematodes on Earth.

Another incredible attribute is their ability of surviving in stasis for an extended period

of time.

In July 2018, Russian scientists collaborated with researchers from Princeton University,

to analyze around 300 prehistoric worms recovered from Russias Sakha Republic, above the

Arctic Circle.

The nematodes were found in permafrost and two of them began to move and eat after being

thawed.

One was believed to be about 32,000 years old, the other approximately 41,700 years

old.

This makes them the oldest living multicellular animals on Earth.

Number 4 Lobsters Research suggests that lobsters dont stop

growing, weaken or lose fertility with age.

They grow through a process calledmoulting’, during which the lobster sheds its hard exoskeleton

prior to growing a new one around a bigger body.

This process repeats itself with greater frequency when the lobster is young and then once every

two or three years after it passes a certain age.

Lobsters also retain their regenerative abilities, which enable them to regrow lost limbs, into

their advanced adulthood.

Its theorized that the reason these blue-blooded creatures are often cited in the discussion

of biological immortality has to do with an enzyme calledtelomerase’.

The chromosomes in animal cells have long repetitive sequences of DNA at their tips,

which are called telomeres.

As the cell divides and the chromosome is replicated, the telomeres become shorter,

in turn reducing lifespan.

Telomerase is an enzyme that repairs these chromosome tips and its expressed in most

vertebrates only during embryonic stages.

Lobsters, on the other hand, express telomerase in most of their bodies as adults, an aspect

which has been associated with their longevity.

Number 3 Planarian Flatworms These creatures are common to many parts of

the world, living in both saltwater and freshwater rivers and ponds.

Planarian flatworms have the reputation of beingimmortal under the edge of a knife’.

Thats because these extraordinary creatures can be cut into pieces and each of them will

regenerate into a separate complete organism.

In just a few weeks, a full organism can be regenerated from a piece as little as one

279th of the already minuscule creature that its been severed from.

This is possible due to adult stem cells called neoblasts, which account for 20 per cent or

more of the total cells in the planarian flatworm.

They reproduce rapidly to replace older cells.

The existing tissue is remodeled to restore the proportion and symmetry of the new worm

that forms from a severed piece.

In the 1950s two American biologists carried out memory experiments on flatworms.

These experiments revealed that theres a chemical basis for memory, which the researchers

dubbed memory RNA.

The working theory was that since ribonucleic acid encodes information, it might also be

used to record stimuli in neurons.

The researchers trained planarian worms to solve a simple maze consisting of bright lights

and electric shocks.

They then ground them up and fed them to untrained planarian worms to see how they would fare

in the maze.

The experiment concluded that those which had been fed trained worms associated the

bright light with shock faster than those that hadnt.

This was attributed to the hormones from the ground animals which modified behavior in

those fed to them.

Even though the results of the experiment were somewhat debatable, subsequent research

proved that some memories can be stored outside the brain.

Although far from applicable in humans, the ability to transfer memories indefinitely

is typically regarded as a form of immortality.

Number 2 Hydra The Hydra is a type of fresh-water organism,

native to tropical and temperate regions.

These small creatures, which only grow to about 0.39 inches in length, are among some

of the most fascinating animals on Earth, for a number of reasons.

Their bodies consist of a simple adhesive foot, called the basal disc and, at the free

end, a mouth part surrounded by one to twelve tentacles.

Each of these tentacles is coated in specialized cells with structures called nematocysts,

which look like minuscule lightbulbs.

They contain a triggering hair on the outside and a coiled thread on the inside.

Upon contact with prey, the nematocysts explosively fire the dart-like thread, which contains

neurotoxins.

If many nematocysts are fired at once, their prey can become paralyzed.

Although these specialized attacks are interesting, theyre not the most astonishing aspect

about these creatures.

The hydra is, so far, the closest known animal to biological immortality.

Named after a mythological creature that was able to regrow its severed heads, the hydra

doesnt appear to die of old age or even age at all.

This is because its stem cells have an indefinite capacity for self-renewal.

Theyre so potent that the Hydra can regrow significant parts of its body, in case of

an accident.

When the hydra reproduces it typically grows tiny clones of itself on its body, which then

separate as they reach maturity.

Three distinct stem cell populations are used to replicate the tissues which form a fully

functioning animal.

All of them have a protein in common calledforkhead box Oalso known as FoxO.

Its believed to be the key factor behind the Hydras immortality.

There are hopes in the scientific community that, by better understanding the Hydra, humans

will one day never have to worry about aging.

Number 1 Leopard Lungfish Leopard Lungfish, also known as marbled lungfish,

are found in swamps, floodplains and river deltas throughout Africa.

Their bodies can grow to nearly 7ft in length, with long tails that taper at the end.

Leopard lungfish also have very long and thin pectoral and pelvic fins, which are used to

glide through the water.

They draw their common name from the dark slate gray splotches that cover their fins

and bodies, creating a marble or leopard-like pattern.

These remarkable creatures have the largest known genome of any vertebrate.

At 133 billion base pairs, the leopard lungfishs genome is also among the largest of any organism

on Earth.

Furthermore, studying the habits of this lungfish may provide a solution for unlocking suspended

animation in humans.

Thats because the lungfish can live on land, in riverbeds and other areas, that have

no freshwater available, for up to 5 years.

The fish will burrow into the ground to form an air bubble, which it breathes out of, as

it enters a dormant state called aestivation.

They slow down their biological clock, surviving in a low energy state in which they dont

need sustenance.

Researchers, whove studied the leopard lungfish in its dormant state, have noticed

that it up-regulates genes related to detoxifying waste and down-regulated genes related to

blood coagulation.

This means that it simultaneously stops the build-up of harmful products in the liver

as well as conserving energy.

Once freshwater is available again, the fish emerges from its cocoon to resume feeding

and mating.

Its believed that it can repeat this cycle indefinitely.

Replicating thissuspended animationin humans would allow astronauts to enter

hibernation during long space missions and doctors to buy more time when operating on

patients in critical condition.

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The Description of 6 Creatures That Live Forever