00:03So cool science!
00:11Why are we multicellular organisms?
00:14Well, that's a wicked cool question, and I don't know about you, but I'm multicellular because I have more than
00:19one phone.
00:21Okay, so your body is made up of hundreds of different cells that all work together as a team.
00:26Oh, and you know what they say, there's no I in team.
00:30Or O, U, G, H, R, or B.
00:35You probably have no idea how big or small the cells are in your body.
00:40Well, you know, I guess, unless you're re-watching this, and...
00:43Well, regardless, the first time you see it, it's gonna be super wicked cool, amazing.
00:47Alright, I'm gonna start with your heart before you depart.
00:51Alright, so red blood cells are about the size of a 7mm screw head.
00:56Oh yeah, and white blood cells would be about the size of this lip balm cap.
00:59About 15mm.
01:01Alright, so your bones are made of cells that roam and make their home within the honeycomb.
01:06And the body of these cells would be about the size of a 20cm penny.
01:09And now, onto the skin of the matter.
01:12Oh, by the way, your dermis is dangling.
01:14Well, call me in!
01:16And those dermis cells would be about the size of this 30mm washer.
01:20And finally, in your brain box, where you're sly as a fox, is where your nerve cells hang out to
01:27rock.
01:27And your brain cells would be about the size of this 10cm rope.
01:30Now, here's what they look like all together.
01:33That's so wicked cool!
01:34Those are some of the cells that make up your body.
01:36And they're so wicked cool, you can see them right there, compared in size.
01:38So, what do these different cells have to do with why we're multicellular?
01:42And, why are these cells different sizes anyway?
01:46Well, don't look at me!
01:48Take a closer look at this!
01:50To understand how multicellular life evolved on this planet, we need to look no further than a fertilized egg's development.
01:57Sometime around about a billion years ago, a single cell most likely divided and got stuck together.
02:03This gave the cells an advantage.
02:05And when these cell groups went to reproduce sexually, this produced other cellular groups, leading to the first multicellular life.
02:11As these cell groups continued to evolve, different cells in the groups evolved different jobs.
02:17By the process of gastrulation, the embryo differentiates into three different types of tissues.
02:23Skin and nerve cells share a common ancestor, as these cells develop from the ectoderm.
02:28Circulatory, muscle, and bone cells share a common ancestor, as these cells develop from the mesoderm.
02:35And finally, the digestive, reproductive, and respiratory cells all evolve from a common ancestor, as they develop from the endoderm.
02:43Every human spent at least 12 to 24 hours as a single cell.
02:47So now you know more about multicellular evolution.
02:51You know, being able to compare the sizes of cells right at home is why science is supercellular.
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