What is Negligible Senescence

A large Great Basin Bristlecone Pine Pinus longaeva, showing both live and dead sections, and streaked grain colors on broad trunk. It is purported to have a lifespan of 4,713 years.
A large Great Basin Bristlecone Pine Pinus longaeva, showing both live and dead sections, and streaked grain colors on broad trunk. It is purported to have a lifespan of 4,713 years. | Source
Aldabra giant tortoise = Aldabrachelys gigantea = Dipsochelys dussumieri
Aldabra giant tortoise = Aldabrachelys gigantea = Dipsochelys dussumieri | Source

Definition of Senescence

In biological terms, senescence refers to the process of aging. It includes accumulative changes which disrupt metabolism resulting in the deterioration of the organism and eventually death. Senescence occurs at two levels:

  1. cellular senescence whereby normal diploid cells lose the ability to divide
  2. organismal senescence involves the aging of the whole organism characterised by
  • the declining ability to respond to stress,
  • decreased reproductive capability,
  • decreased strength and mobility,
  • reduced sensory acuity
  • increased homeostatic imbalance,
  • and increased risk of age-related diseases and associated death rate.

Immortality is a long shot, I admit. But somebody has to be first. — Bill Cosby

Definition Of Negligible Senescence

The term 'negligible senescence' was first used in the 1990s by professor Caleb Finch to describe organisms like lobsters and hydra which showed no signs of senescence as they aged. Negligible senescence refers to a lack of symptoms of aging in a few select animals. These animals:

  1. do not have measurable reductions in reproductive capacities with age;
  2. do not have measurable functional decline with age including strength and mobility;
  3. do not have increased death rate with age.

There is strong scientific grounds to suggest that humans of advanced ages are negligibly senescent.

Just how organisms and some humans that exhibit negilgible senescence accomplish the feat of staying 'young' forever is a hot topic for longevity scientists. If the secret to their longevity and anti-aging could be discovered it could provide a stepping stone for research into extending human longevity by technological means.

Organisms Thought To Be Negligibly Senescent

Organism
Scientific Name
Maximum Observed Life Span (years)
Aldabra Giant Tortoise
Geochelone gigantea
205
Antarctic sponge
Stylocordyla chupachups
est 1550
Blanding's Turtle
Emydoi dea blandingii
77
Eastern Box Turtle
Terrapene carolina
138
Fresh water pearl mussel
Margaritifera margaritifera
210-250
Geoduck saltwater clam
Panopea generosa
160
Great Basin Bristlecone Pine
Pinus longaeva
4718
Hydras
 
biologically immortal
Immortal jellyfish
Turritopsis nutricula
biologically immortal
Koi
Cyprinus carpio
226
Lamellibrachia tube worms
Lamellibrachia luymesi
170
Lobsters
Homarus americanus
100 years
Ocean Quahog clam
Arctica islandica
405
Olm
Proteus anguinuus
103
Painted Turtle
Chrysemys picta
61
Red Sea Urchin
Strongylacentratus franciscanus
200
Rough-eyed rockfish
Sebastes aleutianus
205
Sea anenomes
Actiniaria
60-80
White Sturgeon
Acipenser transmontanus, acipenser
100+
Tuatara
Sphenodon
200

Do Creatures Displaying Negligible Senescence Die?

Creature exhibiting negligible senescence do not age and therefore do not die of age related conditions. These creatures do die however but from the following:

  • predation
  • habitat changes
  • accidents
  • starvation
  • adverse environmental conditions
  • disease

If there was a way of creating the condition of Negligible Senescence in humans would you take the treatment to achieve immortality?

See results without voting

What Causes Aging In Humans And Other Organisms

Most biologists attribute ageing or senescence in humans and other animals to 'telomeres'. Telomeres are the tiny caps on the ends of every chromosome that protect DNA from being corrupted. However, for every cell division, these telomeres become shorter. For each shortening, the cell duplicates itself a little worse than before. When they have become too short, the cell can no longer divide, a phenomenon known as the Hayflick Limit. The decay of telomeres is the biological root of death from old age. In many organisms, the enzyme telomerase maintains the telomeres during cell division. Once the organism reaches maturity, this enzyme stops functioning and the ageing process officially begins.

The Hayflick Limit can have a number of consequences leading to ageing in organisms:

  • Mechanical senescence becomes an issue with many as when cells no longer divide, tissue cannot regenerate leading to wearing out of body parts such as feeding apparatus (teeth, mouth parts) and other body parts such as the gut and muscle tissue.
  • Hormone-driven processes break down which reduce sexual drive, reduce reproductive processes, decrease the desire to feed and cause disease such as arthritis, arteriosclerosis and others.

Click thumbnail to view full-size
 Red rockfish Sebastes aleutianus Ocean Quahog clam Stułbia, Hydra
 Red rockfish Sebastes aleutianus
Red rockfish Sebastes aleutianus | Source
Ocean Quahog clam
Ocean Quahog clam | Source
 Stułbia, Hydra
Stułbia, Hydra | Source

Theories Explaining Negligible Senescence

Natural selection logically would not favor negligible senescence in most circumstances. Reproducing favorable genotypes leads to the reproductive individuals being favored. Once they have accomplished this feat, post-reproductive organisms become redundant and utilize resources to the detriment of reproductive and pre-reproductive individuals. There are, however, cases where negligible senescence is a favorable attribute.

1. Organisms that live in stable but crowded conditions favor longevity.

  • In this condition new opportunities for space for mature individuals arise infrequently.
  • Organisms that outlive their neighbors provide growing space for their own seedlings or larvae when they die.
  • The Bristle cone pine and the Arctic quahog are two species which live in this type of environment and appear to use this strategy.

2. Planarians or flatworms have the capability to perpetually regenerate and thus, exhibit biological immortality.

  • They are able to restore any damaged organ, including their brains.
  • This capability gives them virtual immortality baring predation, accident or lack of resources.
  • An equivalent enzyme to telomerase is present in asexual flatworms and is responsible for the flatworms 'immortality'.
  • This enzyme does not appear to degrade at any point in the flatworm's life cycle thus, their telomeres remain in perfect condition allowing for their perpetual regeneration.

3. In general, asexual reproduction tends to lead to longer lifespans.

4. Organisms with extremely high infant mortality may favor negligible senescence for individuals reaching maturity to ensure longer reproductive capabilities for the few survivors.

5. Organisms such as the worm, Lamellibracia grow in nutrient poor environments. They have a slower growth rate and thus reach the Hayflick Limit at a much slower pace resulting in significantly longer lifespans.

6. Some organisms such as the Walleye have significantly longer lifespans when their habitat is in colder waters.

  • For the Walleye, they experience a five fold increase in longevity in colder waters.
  • Lower temperatures mean organisms reach maturity at a much slower rate.
  • They reach the Hayflick Limit at a delayed rate greatly slowing the onset of age related deterioration.

7. Molting in crustaceans, such as the Lobster, replaces hard tissue, reducing wear and tear and thus, results in a longer life span.

 Diagram depicting the approaches to medically treating aging. "[The] arrows with flat heads are a notation used in the literature of gene expression and gene regulation, and they mean "inhibits". Thus, geriatrics is the attempt to stop damage from c
Diagram depicting the approaches to medically treating aging. "[The] arrows with flat heads are a notation used in the literature of gene expression and gene regulation, and they mean "inhibits". Thus, geriatrics is the attempt to stop damage from c | Source

Treating Senescence By Technological Means

A number of scientist are exploring technological means of increasing human longevity by studying those creatures which display negligible senescence. English transhumanist, Aubrey De Grey founded the S.E.N.S or "Strategies for Engineered Negligible Senescence" in 2002. Through this foundation, De Grey researches medical strategies for increasing the human lifespan with the ultimate goal of providing human 'immortality' through technological means. At this point, research is still a long way from achieving this goal.

Physican Terry Grossman claims to have remedies he proposes will keep many clients alive to the 125 year limit he feels humans can now aspire to. One of his clients is Ray Kurtzweil, famous inventor and futurist.

Resources Used

de Magalhães, PhD, João Pedro. senescence.info. Some Animals Age, Others May Not. 2012

programmed aging. Negligible senescence. 2010

Wilkins, Alasdair. Negligible Senescence These immortal flatworms regenerate like real lifetime Lords. February 28, 2012..

More by this Author


Comments 17 comments

phdast7 profile image

phdast7 4 years ago from Atlanta, Georgia

What a fabulous phrase "Negligible Senescence" and what a fascinating article. I thoroughly enjoyed this. And of course I immediately noticed how many of the examples on your chart are ocean as opposed to land creatures. What do scientists make of that? How is the ocean a more conducive environment for longevity with minimal senescence? Greatly decreased effect of gravity? As our oceans become (sadly) more polluted, I wonder if this will change in any measurable way. Terrific Hub! Sharing. :)


Teresa Coppens profile image

Teresa Coppens 4 years ago from Ontario, Canada Author

Theresa I will have to look into that further. Low temperatures and lack of nutrients seem to be two big factors accounting for slower maturation and thus longer lives both environments being abundant in the ocean. However, gravity may have more effect on ageing mechanisms and I'm not sure if that has even been looked into. Thanks for the ideas for further thought and so glad you enjoyed the topic!


mperrottet profile image

mperrottet 4 years ago from Pennsauken, NJ

This is an absolutely fascinating, well written article. I found it interesting that humans at advanced ages may be negligibly senescent. I guess that means that if you can reach the age that negligible senescence occurs in good shape, you have a good chance of living on for a very long time. I wrote a hub on transhumanism, and I'm not surprised that this is an area that transhumanists are exploring. Wonderful hub, voted up and interesting.


billybuc profile image

billybuc 4 years ago from Olympia, WA

I love your hubs because they give me a chance to revisit things I once taught but haven't thought about in years. Well done, Teresa!


Teresa Coppens profile image

Teresa Coppens 4 years ago from Ontario, Canada Author

mperrottet, I am so thrilled you found my article interesting. I will have to check out your article on transhumanism. Thanks for the feedback and sharing!


Teresa Coppens profile image

Teresa Coppens 4 years ago from Ontario, Canada Author

billy, glad I can bring back old but good memories. Thanks again for the feedback. It is always so very much appreciated!


shiningirisheyes profile image

shiningirisheyes 4 years ago from Upstate, New York

A fine example of the fantastic and amazing results research can provide. Here's to encouraging the continuation and maybe we will be provided with life changing procedures within my lifetime.


Nettlemere profile image

Nettlemere 4 years ago from Burnley, Lancashire, UK

well researched and evidenced. I hope they don't find the secret of eternal life or considerably longer life for humans though. I think we are living long enough as it is.


Teresa Coppens profile image

Teresa Coppens 4 years ago from Ontario, Canada Author

I am sure hoping for a cure to some of the age-related annoyances that are cropping up more frequently LOL! Thanks for stopping by and commenting shiningirisheyes!


Teresa Coppens profile image

Teresa Coppens 4 years ago from Ontario, Canada Author

You have a valid point Nettlemere. Our population has exploded enough. Humans living longer may only compound a very serious problem. However, I think we all would love to be able to grow old while remaining healthier! Thanks for stopping by and reading!


Robin profile image

Robin 3 years ago from San Francisco

Teresa, this is so interesting. I had no idea there was an immortal jellyfish. Your Hubs always pique my interest. :)


Teresa Coppens profile image

Teresa Coppens 3 years ago from Ontario, Canada Author

Thanks Robin. It was so great, I actually got to speak about my article to a grade 12 advanced biology class I am currently teaching during our molecular genetics unit. Glad you enjoyed it!


Robin profile image

Robin 3 years ago from San Francisco

Wow! That's fantastic and well deserved. Your science Hubs are so well done. Congratulations. :)


poetryman6969 profile image

poetryman6969 2 years ago

I see a lot of slow creatures and a lot of lower order creatures. I wonder if there was a devolution pill that conferred immortality, would anyone take it?


Teresa Coppens profile image

Teresa Coppens 2 years ago from Ontario, Canada Author

Cold-bloodedness means slower metabolism and does confer some benefits. There is more to life than just living longer I agree.


Glenn Stok profile image

Glenn Stok 11 months ago from Long Island, NY

It's interesting that if a particular species does not age, that they still will die from other causes that eventually are unavoidable. As time progresses, some disaster will occur, such as those examples that you have listed.

I found your hub extremely interesting, and I learned a lot from you about the process of aging from a cellular level. You explain things very well.

By the way, I found you on Periscope although I know you didn't do any scopes yet. I didn't either.


Teresa Coppens profile image

Teresa Coppens 6 weeks ago from Ontario, Canada Author

Wonder how I got on Periscope then. Glad you enjoyed the article. I'm on my own blog now at Science Alcove. I am making more of an effort to check back on this site more frequently. Thanks for the comment Glenn.

    Sign in or sign up and post using a HubPages Network account.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.


    Click to Rate This Article
    working