"You've got your gonium, looking like several of those little green algae stuck together. And then there's this active pandorina, also packing together several green cells in its colony body as it moves around. And then we see the Eudoria... and then the pleodorina, which looks increasingly like the orderly sphere of the Volvox. In fact, this combination of footage feels less like a family portrait and more like a series of yearbook photos taken from kindergarten through senior year. Expect instead of the striking passage of time documented through the changes in a child's face, this is the striking passage of multicellular evolution documented through the changes in on algal family."

Journey to the Microcosmos- How Did Multicellularity Evolve?

"Multicellularity is one of those things that is so entwined with notions of complexity and the forward marching of evolution that it might feel like it has to be one of those singular evolutionary events: a moment that occurred once or maybe twice, and was maybe too difficult to ever replicate again. But it turns out that making the jump from unicellular to multicellular life has actually happened quite a few times in our planet's history. It's maybe surprisingly not htat difficult a transition. But finding a way to study it is."

Journey to the Microcosmos- How Did Multicellularity Evolve?

Images Originally Captured by Jam's Germs

" Well, volvocine algae primarily reproduce asexually. But where many microbes divide through binary fission--deviding into two daughter cells that then grow and divide again--most volvocine algae are a little more chaotic. They divide through multiple fission, which means that any cell that's going to reproduce start by growing... a lot. If they want two daughter cells, they grow twice as big. If they want to make four, they grow four times as large. And once they get as big as they need to, the alage goes through a rapid series of divisions to produce all those daughter cells in quick succession."

Journey to the Microcosmos- How Did Multicellularity Evolve?

Images Originally Captured by Jam's Germs

"Many of these jumps [in evolution] happened too long ago, and evolution has removed the organisms whose bodies contain the story of how they or their ancestors went from living on their own to teaming up with others. But fortunately, the volvocine algae went about this transistion much more recently--likely around 200 million years ago."

Journey to the Microcosmos- How Did Multicellularity Evolve?

Images Originally Captured by Jam's Germs

"But multicellular is more than just getting big. The big step to taking the volvocine algae from colony to multicellular life involves putting all those cells to work--specialized work. You can see the early days of specialization in the colonial algae through the development of organismal polarity, which is a fancy way of saying that we can define a front and back of the colony. The cells in front are generally large with big eyespots. And as you go to the back, the cells and eyespots get smaller. These differences create a gradient not just in characteristics, but in function. The larger eyespots in front mean those cells will be more sensitive to light, making them responsible for directing the colony."

Journey to the Microcosmos- How Did Multicellularity Evolve?

"In the Chlamydomonas algae, they separate completely through a process called cytokinesis, becoming their own individual self. But with the colonial algae and on up, that cytokinesis is incomplete, leaving the cells connected. Those connections are further supported by an extracellular matrix made up of glycoprotiens. And as the number of cells increased through evolution, so too did the volume of that matrix. At certain points in a Volvox's life cycle, that transparent scaffolding can make up 99% of its volume."

Journey to the Microcosmos- How Did Multicellularity Evolve?