How do jellyfish function without organs that are essential for humans?

We will search online, or using books, for information on our topic and any other related information, using reliable sources.

What is a Jellyfish Made Of

A jellyfish has three layers of “skin”: 

• the epidermis, the thin outside layer 
• the mesoglea, the thick, squishy middle layer
• the gastrodermis, the innermost layer

They also have:

• A very basic nervous system, to react to stimuli
• Digestive cavity, being both its stomach and intestine, with (only) one hole for the mouth and anus 
• Tentacles to move
• Oral arms for protection
• No brains, hearts, lungs, or blood 

In fact, jellyfish are 95% made of water, meaning they don’t actually have a lot of solid material in them.

Background

Jellyfish…

• Have been around for about 500-700 million years (Precambrian Era) 
  • Survived five mass extinctions, one of which killed 70% of life on Earth 
  • Survived three ice ages
• Went through extreme changes in their environment caused by
  • Natural disasters
  • Asteroids
  • Urbanization and pollution
• Come from the phylum Cnidaria
  • One of the oldest branches of the animal family tree
  • Includes anemones and corals
• Most likely the first muscle-powered swimmers
  • Before jellyfish most organisms were moved by the environment and not of their choosing

How Jellyfish Survived

Scientists suggest…

• Survival of the fittest
  • those with superior genes better fit for the environment will survive better than those who don’t. (In the fifth edition of “On the Origin of Species” by Charles Darwin(1869)
• Evolution
  • We think they have evolved to have these superior genes that are fitted for the environment, over an extremely long period of time 
  • In fact, we think jellyfish are still evolving today

Evolution

Scientists studying the moon jellyfish (Aurelia aurita) hypothesize two possible evolutions for how the jellyfish developed the genes that have kept them alive and reproducing for so long.

Non-moving to moving

Most scientists believe they did not move at first, kind of like a coral, and at some point evolved to have a nervous system, muscles, and weaponry, which allowed them to move.

Moving to non-moving

Others believe that jellyfish and other species in the phylum Cnidaria were first muscle-powered carnivores, but over time some of the species like corals and anemones lost the ability to move (lost medusa life stage).

Future Continuation and Research

Here are some topics we would like to research next time:

• Can we control cancer cells?
• Can we use active transport in airplanes, submarines, or diving equipment to breathe in low oxygen places?
• Can we simplify humans, or at least some body parts, to make them more efficient? 

Nervous System

• Jellyfish don’t have a brain, but they can still learn and remember
  • Jellyfish can remember past experiences and learn from them
  • Like if humans did something over and over, their muscles can remember, like how athletes remember posture or dancers remember choreography

• Insead of a brain, jellyfish have a nerve net or nerve ring
  • These detect changes in their environment, like the temperature, gravity, water salinity, oxygen concentrations, and vibrations and currents
  • Then the nerves respond to these changes in the environment by controlling their muscles
• Some jellyfish also have rhopalia
  • Which are clusters of nerve endings in their bells, that help them detect light and balance
  • This helps the jellyfish stay right-side up

How Their Nervous System Affects Humans

Since jellyfish have a simpler nervous system than humans, they would be easier to study, and figure out the mystery of how neuron communication works. With this knowledge, we think researchers could eventually:

• Find solutions to neuron disorders or damages 
  • We could replace damaged parts with a nerve net
  • Generate neuron orders with AI, bypassing the brain or damaged parts
• Help blind people
  • Use rhopalia to help them “see”
  • Help them detect light

Scientists, in October 2006, discovered a protein in jellyfish that might help us treat neurodegenerative diseases.

Respiratory System

Jellyfish use simple diffusion to meet their respiratory needs.

Diffusion: particles moving from high concentrations to low concentrations to meet equilibrium

• Inhaling
  • Their extremely thin ectoderm, a layer in their epidermis, allows dissolved oxygen to simply pass right through into their body, without organs
• Exhaling
  • Their waste leaves through surface cells without organs to meet equilibrium with the water
• Oxygen storage
  • They can also store the oxygen in their mesoglea, and that allows them to withstand waters with low oxygen concentration, just like how we hold our breath

However, jellyfish will always be using the oxygen inside their body through cellular respiration, so they will basically never reach equilibrium with the water

How Their Respiratory System Affects Humans

Jellyfish have a simple respiratory system that we think can help improve engineering, by redesigning airplanes, submarines, and climbing or diving equipment.

• They can take in oxygen as they go higher into the atmosphere or deeper into the ocean, without the need to bring a giant tank of oxygen
  • An issue, though, is that reaching equilibrium in places with such low oxygen concentrations wouldn’t have enough oxygen for a human
  • If we overcame this, exploration would be easier than ever

Recently, in February 2024, scientists looked at the possibility of using a jellyfish as an exploration tool, after turning them into an “ocean-going cyborg”.

Regeneration and Immortality

• Jellyfish can regrow, even with severe harm done to them
  • Jocelyn Malamy, from the University of Chicago, studied the Clytia hemispherica to understand jellyfish regeneration
  • Jellyfish regenerate by sending pre-existing cells to the site of injury, but the precise source is unclear
• Jellyfish, like butterfly, undergo metamorphosis 
  • Metamorphosis: A drastic change in the appearance or habits of an animal from childhood to adulthood
• One species of jellyfish, the Turritopsis dohrnii, can revert back to its younger polyp form if its adult medusa body has been harmed 
  • It would be like a butterfly turning back to a caterpillar, if it was harmed 
  • If the Turritopsis dohrnii kept repeating this, they could theoretically never die, living up to their nickname the “immortal jellyfish”
  • Called transdifferentiation

How Their Regeneration and Immortality Affects Humans

• Humans could learn to regenerate
  • This can save lives, for example eliminating the need for organ transplants
  • Regenerating cells is much safer than using technology we have right now

We could not find anything for this kind of research, as most people were studying immortality, but we think this is as important, and may be easier to research, since it’s similar to healing

No one knows the exact reason humans age, but one theory suggests that it might be related to our DNA is getting damaged and shortened over time.

• Immortal jellyfishes’ DNA don’t shorten over time
  • Scientists think immortal jellyfish have mutated/evolved to have long telomeres
  • Telomeres protect the end of DNA, to prevent it from shortening over time
  • The undamaged DNA appears to be why jellyfish can repeat the cycle of immortality 
• By learning from jellyfish, it seems like if humans had long telomeres, we should be able to stop aging
  • Unfortunately, the answer is not that simple
  • According to two researches in 2023, when humans have long telomeres, it seems to be linked to cancer

Based on these findings, it seems we have to control the uncontrollable cancer cells before we reach immortality in humans.

The Ethical Dilemma of Immortality

There is a controversy on whether scientists should continue this research. 

Humans were not meant to live forever, so if we were to start changing our genes, we would live much longer than we naturally would, adding to issues like overpopulation and global warming. 

The other side is that humans want to live, and choose when to die, not have it determined by nature. 

Other thoughts are “if you replaced all your cells, would you still be you?” and “if you chopped yourself in half, and both halves regrew, which one is the original?”

 

We think these systems have the biggest impact on humans, and so these are the ones we looked at.

Jellyfish can function without organs because they are so simple, and can meet their life needs using simple systems and processes such as nerve nets or nerve rings and diffusion. When they mess up, immortal jellyfish can undergo transdifferentiation to revert to a younger form without harm or injuries.

There are many areas that we can learn from jellyfish that can change our daily lives, from curing neural diseases to immortality. Though most of these researches are still going on and currently have more questions than answers, we believe our future looks promising. However, it is important that we consider the ethical and social issues in these researches. 

Lastly, our hypothesis was generally correct, their nerves do a lot for them, but they didn’t work the way we thought they did. We didn’t even realize that, in theory, jellyfish could live forever.

 

Marine Conservation Society - https://www.mcsuk.org/news/fascinating-facts-about-jellyfish/

NOAA’s National Ocean Service - https://oceanservice.noaa.gov/facts/jellyfish.html

Ocean Conservancy  - https://oceanconservancy.org/blog/2023/08/03/do-jellyfish-have-brains 

IFLScience - https://www.iflscience.com/theres-a-jellyfish-in-the-ocean-that-looks-just-like-a-fried-egg-68137 

Exotic Aquaculture - https://exotic-aqua.com/black-sea-nettle-2/ 

WorldAtlas - https://www.worldatlas.com/is-the-irukandji-jellyfish-deadly.html 

WorldAtlas - https://www.worldatlas.com/what-do-immortal-jellyfish-eat.html 

CBC Kids - https://www.cbc.ca/kids/articles/10-cool-things-you-didnt-know-about-jellyfish 

One Earth - https://www.oneearth.org/five-jaw-dropping-facts-about-jellyfish/ 

UC San Diego - https://today.ucsd.edu/story/first_jellyfish_genome_reveals_ancient_beginnings_of_complex_body_plan 

Virginia Institute of Marine Science - https://www.vims.edu/bayinfo/jellyfish/lifecycle/ 

Science ABC - https://www.youtube.com/watch?v=rUogIRH2XwQ 

Britannica - https://www.britannica.com/science/survival-of-the-fittest 

Smithsonian Magazine - https://www.smithsonianmag.com/smart-news/immortal-jellyfish-could-spur-discoveries-about-human-aging-180980702/

American Museum of Natural History - https://www.amnh.org/explore/news-blogs/immortal-jellyfish

Caltech - https://www.caltech.edu/about/news/building-bionic-jellyfish-for-ocean-exploration

National Marine Aquarium - https://www.national-aquarium.co.uk/blog/five-things-you-didnt-know-about-jellyfish/

Orlando Science Center - https://www.osc.org/are-jellyfish-older-than-dinosaurs

Merriam-Webster - https://www.merriam-webster.com/dictionary/metamorphosis

Smithsonian - https://ocean.si.edu/ocean-life/invertebrates/jellyfish-and-comb-jellies

Medline Plus - https://medlineplus.gov/ency/article/004012.htm 

Chesapeake Bay Program - https://www.chesapeakebay.net/discover/field-guide/entry/comb-jellies 

Jellyfish Art - https://www.jellyfishart.com/blogs/news/jellyfish-evolution 

University of Chicago - https://www.mbl.edu/news/jellyfish-model-wound-healing

Research Gate - https://www.researchgate.net/figure/Anatomy-of-a-true-jellyfish-class-Scyphozoa-Courtesy-of-the-National-Science_fig1_335732493

University of California San Diego - https://mechanism.ucsd.edu/bill/teaching/f21/phil151/Readings/section%202.2-.2.3.pdf

Biopix - http://www.biopix.com/common-jellyfish-moon-jellyfish-aurelia-aurita_photo-53338.aspx

Discover Magazine - https://www.discovermagazine.com/planet-earth/the-immortal-jellyfish

Freepik - https://www.freepik.com/free-photos-vectors/jellyfish-life-cycle

John Hopkins Medicine - https://www.hopkinsmedicine.org/news/newsroom/news-releases/2024/05/variations-in-telomere-lengthening-genes-may-predispose-some-people-to-papillary-thyroid-cancer

Sprout Wellness Clinic - https://sproutwellness.ca/biochemistry-and-iv-therapy/

John Hopkins Medicine - https://www.hopkinsmedicine.org/news/newsroom/news-releases/2023/05/long-telomeres-the-endcaps-on-dna-not-the-fountain-of-youth-once-thought--scientists-may-now-know-why

Science Daily - https://www.sciencedaily.com/releases/2006/10/061027183731.htm 

Cleveland Clinic - https://health.clevelandclinic.org/pee-jellyfish-sting 

We would like to acknowledge our science fair coordinator, Mr. Hagen, our parents, our friends, the researchers that published the information that we have gathered, and any other person who has helped us with this project.