PNB 2250 Exam 4 (UConn) Questions and Answers

PNB 2250 Exam 4 (UConn) Questions and Answers Allen's Rule - Ans:-Animal shapes minimizes heat loss in cold climates and heat gain in warm climates Related to surface/volume Arm length in tropical climates longer than arm length in cold climates Might be related to cartilage growth Effects of temperature Isometric growth - Ans:-◦ A change in size w/o a change in proportion ◦ E.g., as an animal doubles in size, the length of the legs also changes in proportion ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/96 ◦ Relationship between length, surface area and volume (mass) Ex) Fish keep same shape with varying size Bergmann's Rule - Ans:-Larger species are found in colder climates Largest mammals are found in colder climates, while smaller mammals are found in warm climates Inuits (Culturally similiar people of Canada, Alaska, Greenland, etc that eat raw meat) who live at the pole are heavier than Inuits who live closer to the equator NO LONGER ACCEPTED and many people feel that energy availability, escape from predation accounts for the differences Lenth, SA, Volume Relationship (Isometric) - Ans:-For every doubling in length (2x), surface area increases four-fold (4x) and volume increases eight- fold (8x) L=S2 =V3(21 =22 =23)or2-4-8 ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/96 Consider the implications As an animal double in length, the surface area of the lungs increases 4-fold, but there are 8-fold more cells***** An animal would have to double the flow of blood to keep up - hypoxia becomes an issue Allometric scaling (Length, SA, Volume) - Ans:-•Not isometric Increase in L by 33%, results in an increase in surface area by 66% and an increase in volume by 100% A relationship of 1-2-3, instead of 2-4-8. L=2S=3V ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/96 •So a doubling in length will only produce 6x as many new cells, instead of 8x as many new cells in isometric scaling As an animal double in length, the surface area of the lungs increases 4-fold, but there are 6-fold more cells Animals scale allometrically not isometrically - Ans:-◦ Likely due to the constraints on nutrient delivery ◦ So a baby's head is a larger percentage of the whole body size than a young adult. ◦ The body mass grew but the limbs did not grow proportionately Kleiber's Law - Ans:-Animals metabolic rate scales allometrically with volume with a coefficient 1.0 Mr = c(M^0.75) ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/96 c - constant, M - mass, Mr - metabolic rate Assuming cell size doesn't change, in larger species of animals, cells consume O2 at a much lower rate Kleiber's law is only valid if you express metabolic rate per gram animal mass E.g., O2 ml/min/g If expressed as redox coupling efficiency or metabolic efficiency then the exponent is not the same. E.g., amount of energy released by ATP directly resulting in work Scientist argue that the exponent falls between 2/3 and 3/4 Why a coefficient 1.0? (Kleiber's Law) - Ans:-Symmorphosis Biological structures are formed so as to meet but not exceed maximal requirement ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 6/96 No over-engineering If the most you increase respiration is 10-fold, there is no sense in making a heart that can increase blood flow 20-fold Keep in mind that all changes in size are subject to physical constraints Diffusion, diffusion, diffusion Diffusion becomes harder as you get bigger Just as its harder to deliver packages to 100 homes compared to 10 homes Symmorphosis - Ans:-Biological structures are formed so as to meet but not exceed maximal requirement No over-engineering ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 7/96 If the most you increase respiration is 10-fold, there is no sense in making a heart that can increase blood flow 20-fold Diffusion - Ans:-•Effective over small distances only ◦ O2 as a gas moves 4.2 x 10-3 m/sec ◦ O2 in solution moves 2.5 x 10-5 m/sec ◦ In blood, it would take O2 11 hours to move 1 m if there was no circulation •Animal size is predicated on a deliver system that overcomes the limita