Anybody who's seen Terrence Malick's 2011 experimental drama The Tree of Life definitely remembers the roughly 14-minute cosmic sequence where the universe and life itself explodes miraculously into existence in a stunning combination of CGI and a wicked cinematic score. And while the above clip of a European Common Frog embryo undergoing cell division looks like it belongs right in the middle of that sequence—another wondrous life process modeled by a computer—it is in fact real, and unedited.
The stunning (and, let's be honest, slightly squirm-inducing) footage comes via Colossal, and was recorded by YouTuber and "supplier of short educational films/clips about Wildlife behavior and Science subjects," FrancisCheeFilms. In order to record the breathtaking time-lapse, which condenses 33 hours of cell division into 23 seconds of video, the person behind the channel (presumably named Francis Chee), had to customize a microscope that uses "an infinity optical design," which is a design that enables "the insertion of auxiliary optical devices." In this case, Chee used LEDs to light the frog embryo, although the description below the video makes clear that "there [were] countless other variables involved in performing this tricky shot," including taking into account ambient temperature, collection time of the eggs, how the eggs were handled, and what type of water was used.
As far as what you're actually watching in the video, it's cleavage taking place just after a sperm has fertilized an egg. The fertilized egg is a zygote with a diploid nucleus, or a single cell that has two complete chromosomes, one coming from each parent cell. The cleavage of the embryo begins an exponential division of that single cell, from 1 to 2 to 4 to 8, and on and on. Note that the size (volume and mass) of the embryo does not change. Chee puts it pretty succinctly in the video's comments: "Think of cutting up a sphere, no matter how many pieces you cut it up into, the overall size will remain the same."
If you want to see a more complete video of a frog's early growth stages, somebody else in the video's comments posted another pretty fantastic time-lapse. Or you can just marvel at this GIF from the The Tree of Life:
What do you think about this footage? Does it make you feel a bit squirmy too? Let us know in the comments below!