BIO-8 Lecture Notes - Lecture 9: Thermoregulation, Marine Iguana, Homeostasis
Document Summary
Terrestrial environments pose a challenge for animals to balance water, salt, and nitrogen. Homeostasis: an organism"s ability maintains constant internal conditions in the face of a varying external environment. Negative feedbacks: the action of internal response mechanisms that restores a system to a desired state, or set point, when the system deviates from that state. Ex: in mammals, the hypothalamus triggers increased when body temp is below 37c (body organs increase metabolism or increase shivering body temp. rises) and sweating and panting when body temp is above 37c body temp falls. Terrestrial animals, with internalized gas exchange surfaces, are less vulnerable to respiratory water loss than plants. Organisms must exhibit behavior to acquire or remove solutes to maintain the proper concentrations of water and solutes. Animals acquire mineral ions in the water and food they consume water intake and urine excretion eliminate excess salts.
