The idea of cell differentiation is that different cells perform different functions in the body. For example, Epithelial tissue form boundaries in our body, while nervous tissue conducts electrochemical impulses between body parts and systems. Every tissue looks different from each other based on how they could best complete their assigned job in the body. This is why the idea of anatomy (form and function of the body) is so important. If each tissue looked the same, how could they complete all the various jobs that need to be done within the body. The silk from the video is very similar to tissues. Scientists can change the shape of the silk, and in doing so change its purpose. Silk that was meant to replace a small vein would not look the same as silk that was going to be a LED tattoo.
The same concept applies to the fat cells. Brown fat cells and white fat cells do not perform the exact same task; therefore, they are not the same color. Brown fat occurs as a result of homeostasis- “a relative constancy in the internal environment of the body, naturally maintained by adaptive responses that promote healthy survival.” The body senses that it is cold, and so in order to maintain a consistent body temperature, the body it uses brown fat cells to quickly burn calories and make the body warmer. So both the fat cells and the silk are similar to tissues in one very important way: they all have different forms/shapes in order to fulfill different functions/jobs.
For more information on brown fat cells read this article http://tinyurl.com/6m7v5cy.
For more information on the innovative uses of silk watch the TED video by Flo Omenetto.
Sources: Silk Ted video Flo Omenetto.