Energy & Metabolism
30 mechanisms in this category
Adaptive Thermogenesis
A newborn rabbit exposed to 40°F cold activates brown fat immediately, producing a 5× heat increase, maintaining 98°F body temperature despite a 58°F...
Autophagy
When nutrients are scarce, cells transform from construction sites into recycling centers. This is autophagy - literally 'self-eating' - and it's one...
Behavioral Thermoregulation
Behavioral thermoregulation uses environmental positioning and movement to control body temperature. The Namib Desert beetle creates its own microclim...
Circadian Rhythms
Circadian rhythms are internal biological clocks that synchronize organisms to Earth's 24-hour rotation. In mammals, a master clock in the suprachiasm...
Countercurrent Heat Exchange
Countercurrent heat exchange occurs when arteries carrying warm blood run parallel to veins carrying cold blood, allowing heat to transfer between the...
Disposable Soma Theory
Proposed by Thomas Kirkwood (1977), disposable soma theory explains aging as an allocation strategy rather than a defect. Natural selection optimizes...
Ectothermy
Why did Mailchimp - a company that never raised venture capital - sell for $12 billion while well-funded competitors like Constant Contact struggled?...
Endothermy
Why would evolution select for a metabolism that costs 10 times more energy than the alternative? The same reason venture capitalists fund startups bu...
Entrainment
Entrainment is the process by which external cues (zeitgebers) synchronize internal biological rhythms to the environment. Without this daily light si...
Freeze Tolerance
When crisis hits, which parts of your business can you afford to let freeze? The wood frog knows: 65% of its body water turns to ice each winter. Its...
Gigantothermy
The leatherback sea turtle should not exist. A reptile—nominally cold-blooded—that maintains body temperature 18°C above frigid Arctic water. Yet leat...
Glycolysis
Glycolysis happens in the cytoplasm. It breaks glucose into pyruvate, producing a small amount of ATP quickly. This is the sprint metabolism - fast bu...
Hydraulic Limits
Above approximately 100-130 meters, water column tension in the xylem exceeds what the vascular system can sustain, causing cavitation (air bubbles th...
Jet Lag
Jet lag occurs when external time (local time zone) mismatches internal time (circadian rhythm). The SCN requires approximately 1 day per time zone to...
Kleiber's Law
In 1932, Swiss agricultural scientist Max Kleiber at UC Davis discovered that biology's most fundamental accounting doesn't follow intuition. Metaboli...
Krebs Cycle
How did Adobe transform from a company selling $2,500 software boxes to one generating over $21 billion in recurring revenue? By discovering the busin...
Metabolic Pathway Organization
Cellular metabolism is organized into modular pathways: sequences of reactions that convert starting substrates into end products through defined inte...
Nitrogen Fixation
Legumes and alders harbor symbiotic bacteria that convert atmospheric nitrogen to forms accessible to plants, enriching nitrogen-poor soils. Subsequen...
Non-Shivering Thermogenesis
When the temperature drops, your first response is to shiver - involuntary muscle contractions that generate heat at 5x your resting metabolic rate. B...
Oxidative Phosphorylation
Oxidative phosphorylation happens in the mitochondrial membrane. It uses those high-energy electrons to drive the production of most of your ATP - rou...
Regional Heterothermy
Regional heterothermy allows different body regions to operate at different temperatures. Bluefin tuna swim in 50°F water but maintain red muscle at 8...
Rete Mirabile
The Latin name tells you everything: rete mirabile, the 'wonderful net.' Named by Galen 2,000 years ago, this network of intertwined arteries and vein...
Shivering Thermogenesis
When a crisis hits, how do you generate maximum organizational output immediately? Shivering thermogenesis provides the biological template: involunta...
Sirtuins
Every cell experiences 10,000 DNA lesions per day from oxidative damage, spontaneous depurination, and copying errors. Sirtuins are the repair crew -...
Social Thermogenesis
Why do competitors cluster together? Silicon Valley, Wall Street, Hollywood, Detroit—industries that could theoretically locate anywhere choose to pil...
Square-Cube Law
Galileo articulated it first in 1638: giant animals couldn't simply be scaled-up versions of small animals. The math is unforgiving. As organisms grow...
Supercooling
When water freezes, ice crystals form. These crystals expand, rupturing cell membranes, destroying tissue. Yet the Arctic ground squirrel survives wit...
Thermal Runaway
What kills you in a heat wave isn't the temperature - it's the tipping point where your cooling mechanisms can no longer keep pace with heat accumulat...
Thermal Windows
Thermal windows are body structures with high surface area and minimal insulation that allow selective heat dissipation. The Toucan's bill (30-40% of...
Thermoregulation
Temperature regulation is the process by which organisms maintain optimal internal temperature despite external conditions. Every chemical reaction ha...