Are there any immortal organisms?

[jimmydasaint]

I remember hearing about organisms that are posited to be immortal. However, is this just a myth or are there organisms which can be considered immortal due to physical changes?

[moth]

I got the impression, from the story of Henrietta Lacks, that HeLa was considered to be immortal. I don't know if it can survive without life-support, but the contamination of so many other cell lines suggest to me, it can.

[CharonY]

There are cell lines that can divide indefinitely. However it is often not clear whether an individual has the same capability. I.e. after a few generations it is possible that the population is taken over by the daughter cells and the original ones may have been lost.

 

That is probably a common problem in determining biological immortality. There may be mechanisms and traits (e.g. continuous regeneration/replication) that would suggest immortality, but if you track an individual there is a good chance that it still dies. It is then not clear whether it was just due to whatever unknown mechanism or really a mechanism of senescence.

[Schneibster]

How about the giant fungus under (IIRC) Minnesota?

 

Later: did a little research, the one in the Northern Midwest has been eclipsed by one in Oregon:

 

http://en.wikipedia.org/wiki/Largest_organisms#Fungi

 

2400 years old. Hmmm. Aren't bristlecone pines older than that?

Edited April 10, 2014 by Schneibster

[Moontanman]

Immortal jellyfish...

 

http://en.wikipedia.org/wiki/Turritopsis_dohrnii

[CharonY]

I am not sure which you are referring to. However, fungi, or more precisely, their fruiting body, just looks like a singular organism. However they actually basically grow as hyphae which is a somewhat organized cell colony that can regrown and proliferate somewhat independent from the rest of the structure. At this point it becomes tricky to argue whether it is fair or a matter of semantics to call it immortal as the overall structure does not exhibit senescence, whereas each individual parts have been thoroughly replaced.

This is basically the case for all organisms which are on the edge between uni and multi-cellularism, where the individual elements still often exhibit partial autonomy.

[EdEarl]

 

wikipedia

If the mortality rate remains constant, the rate determines the mean lifespan. The lifespan can be long or short, even though the species technically "does not age".

Sanicula is an herb, native to Europe and the Americas, which lives about 70 years in the wild. Old saniculae do not die at a higher rate than younger ones.[citation needed]

Sea urchins, lobsters and some clams have relatively high rates of mortality in the ocean, but mortality does not appear to increase with age.[citation needed]

Hydras were observed, in a study published in the journal Experimental Gerontology, for four years without any increase in mortality rate.[2]

There are stranger examples of species that have been observed to regress to a larval state and regrow into adults multiple times:

The Hydrozoan species Turritopsis dohrnii is capable of cycling from a mature adult stage to an immature polyp stage and back again. This means that there may be no natural limit to its life span.[3] However, no single specimen has been observed for any extended period, and it is impossible to estimate the age of a specimen.

The larvae of carrion beetles have evolved to undergo a degree of "reversed development" when starved, and later to grow back to the previously attained level of maturity. The cycle can be repeated many times.[4]

[Acme]

...

2400 years old. Hmmm. Aren't bristlecone pines older than that?

Yes; the oldest living known specimen is over twice that age. I happened to be researching the question lately and ran across the following.

5,063 years old Great Basin bristlecone pine - Pinus longaeva: White Mountains, California, United States: Oldest known currently living tree. Tree cored by Edmund Schulman, age determined by Tom Harlan

source: >> http://en.wikipedia.org/wiki/List_of_oldest_trees

 

From the same source and concerning clonal colonies, there is this.

 

Pando 80,000 to 1,000,000 year old Quaking aspen - Populus tremuloides: Fishlake National Forest, Utah, United States: Covers 107 acres (0.43 km2) and has around 47,000 stems (average age 130 years), which continually die and are renewed by its roots. Is also the heaviest known organism, weighing 6,000 tonnes.

All-in-all, I see no evidence that any individual living thing is immortal.

Edited April 11, 2014 by Acme

[obuekwe emeka]

Most hydrozoans e.g. Hydra vulgaris do not undergo senesence

[petrushka.googol]

If we tweak the definition of life....then maybe viruses could fall in that category...but again that is open to debate on several premises.

Edited April 11, 2014 by petrushka.googol

[Genecks]

Immortal jellyfish...

 

http://en.wikipedia.org/wiki/Turritopsis_dohrnii

 

Nice find. I don't recall hearing or reading about this thing before. i was a child in the mid 1990s, so I doubt I would have heard or read about it.

 

Here is an interesting year of 2012 excerpt from the New York Times in relation to the animal:

 

 

You might expect that biotech multinationals would vie to copyright its genome; that a vast coalition of research scientists would seek to determine the mechanisms by which its cells aged in reverse; that pharmaceutical firms would try to appropriate its lessons for the purposes of human medicine; that governments would broker international accords to govern the future use of rejuvenating technology. But none of this happened.

 

 

http://www.nytimes.com/2012/12/02/magazine/can-a-jellyfish-unlock-the-secret-of-immortality.html?src=me&ref=general&_r=0