What caused the delay of over a billion years in the evolution of multicellular animals after the evolution of single cell eukaryotes?
Thus, for instance, all the cells in a multicellular organism represent one clone derived from the fertilized egg.
The evolution of multicellular animals from unicellular protists is one of the key transitions of life on Earth.
Not only are cells in multicellular organisms specialized, they are precisely arrayed in particular spatial patterns.
Flowering plants are multicellular organisms where cell division plays a significant role in growth and development.
This could have been the origin of both multicellularity and the requirement for cell death in multicellular organisms.
From sponges and coelenterates, I learned about the fundamentals of multicellularity : how cells can communicate and cooperate, how you can build a more complex whole from simpler parts.
Although highly derived, it is nevertheless the prototypical eukaryote, unencumbered by the requirements of multicellularity .
Thus it seems likely that the volvocine algae may retain in their genomes more evidence of the pathway that they followed from unicellularity to multicellularity than members of the major multicellular groups do.
This supracellular, or organismal, approach towards multicellularity seems to have allowed sessile plants to adapt to life on land and to evolve even within hostile environments.