In particular, the jump from unicellular to multicellular life is (was) one of the top leading candidates for the Great Filter. https://en.wikipedia.org/wiki/Great_Filter
Importantly, it was one of the filter candidates "behind" us. It will be exciting to see if other potential filter steps can be so conclusively eliminated over time.
A good demo video: https://www.youtube.com/watch?v=amjuJJwI3iM
On a planet with twice the Earth's mass, it would take a larger-than-Saturn-sized rocket to put a Mercury-sized payload into orbit.
EDIT: And said Mercury-sized payload would have to spend more of its mass on heat shielding than the human Mercury capsule if it's intended to come back down.
Mercury was a small space capsule containing 1 person designed to last a few hours in space. The Saturn V rocket was until recently the most powerful rocket ever launched, and took 3 crew, a crew module, a lander module, and payloads, to the moon.
There's just so many unknowns.
https://www.newscientist.com/article/mg21028184-300-lab-yeas...
That being said I’m not too shocked. The transition from unicellular to multicellular has always seemed like less of a hurdle to me compared to the start of unicellular life itself.
It took "only" < 400 million years for life to develop, meaning unicellular life, but it took 3 billion years for multicellular life to develop. If we apply this basic rule, multicellular life seems the hard thing. Of course though, statistics wise this is pretty crappy ground to stand on because we only have one sample :).
The jump from prokaryotic to eukaryotic is far more intimidating.
- "Metallicity": We probably need a recent / "Population I" star, i.e. it' s probably unlikely that there can be civilizations much older than us (in astronomical dimensions): https://en.wikipedia.org/wiki/Stellar_population#Population_...
- In 1.1 billion years from now, the Sun will be 10% brighter than it is today, and this increase in luminosity will also mean an increase in heat energy, which Earth’s atmosphere will absorb. This will trigger a moist greenhouse effect here on Earth that is similar to the runaway warming that turned Venus into the hellish environment we see there today. So we have appeared only after 80% of the "usable" life span of our star has already been over -- a window that might be easy to miss (an larger stars burn even faster)
The ability of wild-type C. reinhardtii to form palmelloids suggests that the founding population in our experiment already possessed a toolkit for producing multicellular structures. However, while the palmelloid condition is expressed facultatively in wild-type C. reinhardtii, the strains that evolved in our experiment are obligately multicellular.
Maybe I'm not familiar with how this term is used in biology but given the above it seems the "de novo" claim in the paper title is a little sensationalist.
There's also caulerpa (https://en.wikipedia.org/wiki/Caulerpa) can be large but only have a single cell, googling turns up several other surprisingly large single cells.
Maybe if it's big enough, but there's a huge cost to being big and the cot is harder to bear for more herbivorous cells. For most organisms the better survival strategy is probably to be more numerous and accept a certain level of attrition, hence ants outnumbering humans.
The postulation being organisms have a pressure (from predators) to form groups and eventually societies. Essentially, they'd either survive by evolving to be social, evolve defense mechanisms or die out. Social evolution may actually be the shortest path for non-aggressive species because they simply have to bare one another, as opposed to evolve long claws or something.
Very hard to prove, but our model showed given the options social interactions appeared more likely with basic reward circuitry.
As the 'stickiness' doesn't really pose a disadvantage to the single-celled organism, the trait persists even after the predator is removed.
In short, can a collection of 'stickier-than-normal' single-celled organisms truly be referred to as a multicellular organism? Aren't they stretching the definition of multicellular? Each of the units, after all, reproduces on its own and there is no differentiation.
Interesting that the changes were then stable over many generations once the predator was removed.
