#multicellularity

[johniac]

SciTech Chronicles. . . . . . . . .April 22nd, 2025

[gwydionmisha]

A Multitalented Scientist Seeks the Origins of Multicellularity

[forms-and-phyla]

While mushrooms and animals evolved multicellularity independently, it's true that they have much in common - their metabolisms are closer to each other than to that of plants, meaning sessile animals and (macroscopic) fungi will have similar needs, and will absolutely evolve the same vibes sometimes!

Phylum #2: Porifera, the sponges!

While not the most basal animals, sponges are probably the closest to what the first animals looked like. The basic shape is pretty simple: a surface covered in numerous pores takes in water, funneling it out through a large chimney.

The cells in charge of driving water through the pores, choanocytes, are surprisingly close in function to our closest unicellular relatives, choanoflagellates, hinting at a deep evolutionary connection between us and them. It is believed that the first sponge-like animals arose through multiple choanoflagellate-like cells sticking together, beating their flagella in tandem to filter water together!

While the basic sponge body plan is pretty simple, they have evolved numerous variations on it. Glass sponges have become delicate creatures built upon a silica skeleton, and have been reported to live for up to tens of millenia at the bottom of the ocean!

Meanwhile, deep-water carnivorous sponges capture small prey like crustaceans, with velcro-like hooks and enigmatic balloon-like structures!

[mindblowingscience]

All bacteria exist as single cells at some point in their lives – except for one kind, known as multicellular magnetotactic bacteria (MMB), that is. Scooped from the sulfide-laden sediments of a tidal salt marsh in Massachusetts, scientists think these MMBs could provide clues to our own evolutionary history, as a kind of missing link between simple, single-celled life forms and complex multicellular organisms like ourselves.

Continue Reading.

[opens-up-4-nobody]

can I just say, I followed you for your beautiful art style and use of colours and I stayed for your beautiful art style and use of colours AND cyanobacteria. Like, I know nothing about them because I'm a classic lit major but more often than not I find myself reading your posts about cyanobacteria with unexpected interest and fascination

HAH! I'm glad u enjoy them bc I feel absolutely intolerable when I talk abt them lol. But also. I am the cyanobacteria evangelist. I am the patron saint of cyanobacteria.

[confusedreety]

the mitochon-chia is the powerhouse of the cell.......

[transpotato5]

the empire grows

[fungi-and-a-funguy]

Daily Fungi Fact 16: The (maybe)fungi Ourasphaira giraldae is an extinct species on land that lived over 1 billion years ago, that was before plants were on land. Most experts believe that fungi colonized land before plants grew on land, however fungi fossils from before the Devonian period are rare and often disputed, this is due to fungal fruiting bodies being easily degradable and most fungi structures being microscopic, leading to many fungi fossils resembling other microscopic organisms.

[asordidbarwere]

having a background in biology is its own little curse because I'll be wiping down the shower wall and thinking "gee this is probably slime mold! which means it has Thoughts"

[blatentmisinformation]

Four billion years ago complex multicellular life forms evolved temporarily before rapidly going extinct, leaving behind only trace fossils from which their existence can be inferred.

[unopenablebox]

i love TAing. some parts of it are stressful but running office hours and just getting to talk through a concept with the students until we've identified the source of their confusion and successfully resolved it is so satisfying and fun.

[suzilight]

Meet the first animal found that doesn't need oxygen to live

In 2020, scientists discovered a jellyfish-like parasite that lacks a mitochondrial genome – the first multicellular organism ever found with such an absence. This means it doesn't breathe; in fact, he lives completely free from oxygen dependence.

Species Henneguya salminicola 

This discovery doesn't just change our understanding of how life might work here on Earth – it could also have implications for the search for extraterrestrial life. Life began developing the ability to metabolize oxygen – that is, breathe – more than 1, 45 billion years. A larger archaeon engulfed a smaller bacterium, and somehow the bacterium's new home was beneficial to both parties, and the two remained together.

This symbiotic relationship resulted in the joint evolution of the two organisms and, eventually, the bacteria installed in them became organelles called mitochondria. Every cell in your body, except red blood cells, has a large number of mitochondria, and these are essential for the respiratory process.

They break down oxygen to produce a molecule called adenosine triphosphate, which multicellular organisms use to power cellular processes.

We know that there are adaptations that allow some organisms to thrive in low-oxygen or hypoxic conditions. Some unicellular organisms have developed mitochondria-related organelles for anaerobic metabolism; but the possibility of exclusively anaerobic multicellular organisms has been the subject of some scientific debate.

That was until a team of researchers led by Dayana Yahalomi of Tel Aviv University in Israel decided to take a new look at a common salmon parasite called Henneguya salminicola.

It is a cnidarian, belonging to the same phylum as corals, jellyfish and anemones. Although the cysts it creates in the fish's flesh are unsightly, the parasites are not harmful and will live with the salmon throughout its life cycle.

Hidden within its host, the tiny cnidarian can survive quite hypoxic conditions. But it's difficult to know exactly how this happens without looking at the creature's DNA – and that's what the researchers did.

They used deep sequencing and fluorescence microscopy to conduct a detailed study of H. salminicola and discovered that it had lost its mitochondrial genome. Furthermore, it has also lost the capacity for aerobic respiration and almost all nuclear genes involved in the transcription and replication of mitochondria. Like unicellular organisms, it has developed organelles related to mitochondria, but these are also unusual – they have folds in the inner membrane that normally are not seen.

The same sequencing and microscopic methods in a closely related cnidarian fish parasite, Myxobolus squamalis, were used as a control and clearly showed a mitochondrial genome.

These results showed that here was, finally, a multicellular organism that did not need oxygen to survive.

Although H. salminicola is still a mystery, the loss is largely consistent with a general trend in these creatures – a trend toward genetic simplification. Over many, many years, they basically evolved from a free-living jellyfish ancestor into the much simpler parasite we see today.

They lost most of the original jellyfish genome, but retained – strangely – a complex structure reminiscent of jellyfish stinging cells. They don't use them to sting, but to cling to their hosts: an evolutionary adaptation of the free-living jellyfish's needs to those of the parasite. You can see them in the image above – they're things that look like eyes.

The discovery could help fisheries adapt their strategies to deal with the parasite; although it's harmless to humans, no one wants to buy salmon full of strange little jellyfish.

But it's also an incredible discovery to help us understand how life works.

“Our discovery confirms that adaptation to an anaerobic environment is not exclusive to single-celled eukaryotes, but also evolved in a multicellular parasitic animal,” the researchers explained in their paper, published in February 2020.

“Therefore, H. salminicola provides an opportunity to understand the evolutionary transition from an aerobic to an exclusively anaerobic metabolism.”

The research was published in PNAS .

[nucleargnocchi]

sometimes i think i'm making up my anxiety for attention and then i spend lots of time being... anxious... about it. brains are so bizarre and cruel i don't want mine anymore

[kamalkafir-blog]

Morphodynamics of human early brain organoid development

Experimental methods Stem cell and organoid culture We used the following induced pluripotent stem (iPS) cell line for all experiments (also see Supplementary Methods Table 1): histone2B–mEGFP that uniformly labels nuclei (cell line ID: AICS-0061-036, cl.036), mEGFP–β-actin that uniformly labels ACTB (cell line ID: AICS-0016-184 cl.184), mTagRFP–T-CAAX that labels cell membrane (cell line ID:…

[myspineisthebassline]

why can rotifers get pregangenant

[snailchimera]

LET THEM BE CORAL

Also in what fucking universe are corals almost protists

who let biologists play dnd