A unicellular organism becoime multicellular through replication before splitting into flagellated daughter cells.

Scientists Reveal a Shocking Solution to The Chicken or Egg Paradox

This is so ccol. The organism, Chromosphaera perkinsii, is part of a group that has been proposed to serve as surrogates for multicellularity. The single cell replicates and  then replicates again without separating, forming a 4 cell bundle. Just likea fertilized egg does.

Fertilized eggs  continue dividing and form a multicellular sack of cells with a hollow center, called a blastula.

It turns out these primitive organsms form something similar. Instead of differentiating into hundreds of different cell types, these simple colonies actually do show some simple differentiation into two types. Then after spending a long time as a big colony of cells, the cells brek apart and form a flaellated cell (kind of like a sperm) and swim off, to start things all over again.

I mentioned a few days ago what life under a Snowball Earth might have looked like – large ball-like, multicellular colonies resembling  C. perkinsii .

So, the path to multicellular organisms might be something like C. perkinsii  staying together and seeing its cells differentiate from 2 types into hundreds.

With one cell retaining the ability to form a sperm-like flagellated form and one retinaing the ‘egg’. Pretty cool. Still lots of biology that needs to happen – like meiosis – but an interesting path and one that fits with the emergence of multicellular organisms following the Snowball Earth period.