Bio 191 Exam 2 Questions & Answers 100% Verified!!

Endothermic Fish: rete mirable - ANSWERBluefin tuna, swordfish; heart pumps blood to gills; cold blood flows from gills to body in superficial arteries; arterial blood flowing into muscles warmed by venous blood flowing out of muscles Torpor - ANSWERState of reduced metabolic activity in which the heart rate and respiratory system slow down Hibernation - ANSWERResponse to cold (triggered by photoperiod) Aestivation - ANSWERResponse to heat or drought Nitrogenous Wastes - ANSWERammonia Ammonia - ANSWERdirect product of metabolism via deamination of proteins and nucleic acids; toxic, so requires lots of H2O; restricted to aquatic organisms; FW fish and tadpoles Urea - ANSWER100,000x less toxic than NH3; requires less H2O; mammals, adult amphibians, marine fish and marine turtles; excreted in H2O as urine; energetically expensive but conserves H2O by reducing toxicity Uric Acid - ANSWERLow toxicity; very insoluble in H2O, so excreted as paste; birds, reptiles, land snails and insects; energetically expensive but very effective @ conserving H2O Hypotonic Osmoregulator - ANSWERconstantly loses water through osmosis; therefore has to drink constantly; gills actively transport out Cl- Hypertonic Osmoregulator - ANSWERconstantly gains water through osmosis; produces copious amounts of dilute urine; gills actively transport Cl- in Osmoconformity - ANSWERthe osmotic pressure, or osmolarity, of the organisms cells is equal to the osmotic pressure of their surrounding environment Major sources of H2O loss - ANSWERgas exchange organs; urine Excretory Systems - ANSWERessential to homeostasis b/c they dispose of wastes and r