BIOLOGICAL IMMORTALITY

Some creatures truly have everlasting youth

As humans, immortality seems like a far- fetched, mythical concept that we can never attain. However, these creatures’ systems have been created in such a unique way that they are theoretically biologically immortal!

Backward aging jellyfish Turritopsis dohrnii

This creature is one of the rare few species that has attained biological immortality. In theory, these creatures never die. But what is the secret of these jellyfish?

It’s very simple, actually- when in stressful situations, they simply leave their current stage of maturity and turn back into an earlier stage in their life where they were merely small blobs of cells.

Here’s how this works:

A jellyfish comes to life upon fertilization after which it turns into a planula. This is its larval stage.
The planula then latches onto a surface- any surface such as rocks or the ocean floor- and slowly grows into a polyp. At this stage, the jellyfish looks like a tube with an opening on one end and a foot-like structure at the other end.
The polyp multiplies and turns into a colony of polyps which feed through common feeding tubes.
Then, the polyp breaks into separate segments which are stacked on top of each other and can break away from the rest of the polyps. Another alternative is that the polyp forms an outgrowth called a ‘bud’, which is also capable of breaking away from the rest of the colony. Which one of these two outcomes occur is based on the species of the jellyfish.
It then turns into a mini jellyfish called an ‘ephyra’ after which it becomes a mature jellyfish called a ‘medusa’.

Now, if the medusa faces any threats such as starvation, it turns back to a blob of tissues which then grow into the polyp phase. Thus, the Turritopsis dohrnii has attained biological immortality by simply reversing its life cycle.

An infinitely self renewing organism

HYDRA

These mysterious creatures are such widely known “immortal” organisms that there are even Greek myths about them!

Hydra is a genus of freshwater organisms which have a tubular body with tentacles and an adhesive foot.

The peculiar thing about these species is that they do not undergo senescence, which is the process of deterioration due to old age. In fact, their stem cells have the potential to self-renew infinitely. This is due to a set of genes called the FoxO genes which determine the duration of a cell’s life. In Hydra’s case, there is an excessive expression of these genes, which leads to their continuous regeneration.

When scientists prevented these genes from being expressed in this organism, they began to show signs of ageing. They do not know the exact science behind this, but do know that these genes do play a vital part in their everlasting youth.

There are a few more such creatures that have developed the mysterious ability to put a hold on their aging process and attain biological immortality. But how long did this really take? Would human beings ever evolve to attain biological immortality? And if yes, then what would that mean for our world and our environment? We’ll just have to wait and watch to know if we are fated on a similar course as these creatures.