Prof. Mark Allegro, at MBL in Woods Hole, decided to help the BioBus capture live cell division on film Wednesday, July 13, 2011!
The video can be viewed here:
This synchronized proliferation of cells is the beginning of life. In the video, what appears to be a round boundary starts out filled by two seemingly-large, but really microscopic, cells. This boundary, and its contained cells, is what make up an embryo, or the first sign of a living thing after an egg is fertilized. That ball is really just the beginnings of a baby…sea urchin. Well, that sea urchin must have some very proud parents, because the BioBus has decided to use it as an example depicting the early development of practically all organisms: “Look, that’s my developing urchin on TV!”
While the video made the division of these cells appear to only take a few seconds, in reality the event was recorded over the span of an hour and was sped up for our enjoyment. If you pay close attention to the embryo, you will see that the cells making up the embryo keep getting smaller as they divide. They have to do this to divide as fast as they do. They cannot just stop to refill on cell juice (a.k.a. cytosol), or other parts just yet! So, they divide a few hundred more times until the cells are extremely numerous and tiny, then they reorganize themselves in specific shapes, and they grow in size by taking in nutrients. The subsequent embryonic divisions and reorganization of cells actually precede the formation of something more universally recognizable: a fetus, or a baby.