Big Idea 2: Biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis.

Passage 1:
“Of course, just because we can’t survive a true deep freeze doesn’t mean our bodies haven’t evolved many ways to manage the cold. They have. Not only is your body keenly aware of the danger cold poses, it’s got a whole arsenal of natural defense. Think back to some time when you were absolutely freezing-standing still for hours on a frigid winter morning watching a parade, riding a ski lift with the wind whipping across the mountain. You start to shiver. That’s your body’s first move. When you shiver, the increased muscle activity burns the sugar stored in your muscles and creates heat. What happens next is less obvious, but you’ve felt the effect.” (page 35)

Enduring Understanding (Number and Letter): 2.C.1
Explanation:
Organisms utilize feedback mechanisms to manage their internal environments and respond to external environmental variances. Dynamic homeostasis is controlled through …show more content…
Brown fat is a specialized heat-generating tissue present in newborns and some adults that is activated when the body is exposed to cold temperatures. When blood sugar is delivered to a brown fat cell, it is instantly converted to heat rather than being stored for future energy as it is in a typical fat cell. Scientists have labelled the brown fat process as nonshivering thermogenesis since it’s heat production without muscle movement. Other methods of regaining homeostasis in cold environments have downfalls. Shivering, for instance, will only work for a few hours; once the blood sugar stores in your muscles are depleted and fatigue sets in, it fails to work. On the other hand, brown fat can consistently generate heat as long as it’s fed, and it doesn’t require insulin to transport sugar into cells unlike most