I was watching a documentary recently, and I saw a particular type of organism, and the first thing that came to my mind was “Are those cornflakes?” because they looked like that at first glance but when I continued with it, I realized that it was far from those dry flaky cereals that you need to put milk into.
https://upload.wikimedia.org/wikipedia/commons/2/2d/Acoel_Flatworms_%28Waminoa_sp.%29_on_Bubble_Coral_%28Plerogyra_sinuosa%29_-Panglima%2C_Pulau_Mabul%2C_Sabah%2C_Malaysia.jpg
[image; wikimedia](https://commons.wikimedia.org/wiki/File:Acoel_Flatworms%28Waminoa_sp.%29_on_Bubble_Coral_%28Plerogyra_sinuosa%29_-_Panglima,_Pulau_Mabul,_Sabah, _Malaysia.jpg)
What you see in the Image above is an Acoel flatworm which is a marine flatworm. While they are animals, we could refer to them as somewhat like a plant because they need sunlight just like plants need sunlight. Actually, they need this sunlight to survive and so they use their simple eyes called the Ocelli to look for places with proper sunlight on coral reefs.
These flatworms are carnivores, eating prey by engulfing them with the body and trapping them in the mouth and excreting waste from the mouth as well, so why do they need to sit in the sun all day? Acoels are home to algae that produce sugar during the process of photosynthesis and researchers think they share the sugar with their host which is why the flatworms stay under the sun, also the waste they excrete serves as fertilizers for them.
These two organisms are different species but need each other to survive. Researchers believe that the red cells of the Acoel release toxins that keep predators away from the algae and so they can be alive. This is because without the algae, the Acoel cannot survive which makes it a holobiont.
If the Acoel is cut into 2, the one with the head goes away, while the other half with no head creates a new head or even two at both ends. If two heads are made, they separate from themselves and start to live afresh. They can cut themselves into several parts and form a new life as many times as possible and would continue to live. This is possible because the flatworm is made up of stem cells that can help it grow whatever part it needs to live on. During the time of the divide, they are reliant on the energy from the algae to survive before a head is formed.
Just like Acoel, there are other holobionts in our world, and the goal of the organisms in the relationship is to keep themselves alive.
For Further Reading and Research
https://www.cell.com/current-biology/pdf/S0960-9822%2809%2900755-6.pdf
https://sikesj61.wixsite.com/sikeslab
https://pmc.ncbi.nlm.nih.gov/articles/PMC10163032
https://pmc.ncbi.nlm.nih.gov/articles/PMC1933604/
https://news.stanford.edu/stories/2024/05/regenerating-worms-have-genetic-control-over-their-algal-partners
https://pmc.ncbi.nlm.nih.gov/articles/PMC3789126/