Ch. 1

Question 1

Propose reasons why animals depend on phenotypic plasticity, instead of maintaining all their systems in a maximum state of readiness at all times.

Answer 1

Energy maintenance

Question 2

An expert on crabs was asked, “Why are the two different life stages different in color?” She replied, “The larvae accumulate orange-colored carotenoid pigments, but the adults do not.” Did she recognize all the significant meanings in the question asked? Explain.

Answer 2

No, she did not provide any physiological explanations for why the crabs are different colors. Why do the larvae accumulate the orange pigments?

Question 3

At least three hemoglobin alleles in human populations alter hemoglobin structure in such a way as to impair the transport of O2 by the blood but enhance resistance of red blood cells to parasitization by malaria parasites. Explain how such alleles exemplify pleiotropy, and discuss whether such alleles could lead to nonadaptive evolution of blood O2 transport in certain situations.

Answer 3

Pleiotropy occurs when one gene leads to multiple phenotypes. In this case, these genes are not only affecting hemoglobin structure, but also RBC resistance to malaria parasitization. In an environment where malaria spread is common, nonadaptive evolution may occur when increased malaria resistance is necessary.

Question 4

Name 4 ways physiology can be studied.

Answer 4

Anatomy
Biochemistry
Cellular
Behavior

Question 5

Explain the physiology of lightning bugs ANATOMICALLY.

Answer 5

The lantern is the organ lightning bugs use to light up at night. Further study shows hundreds of air-filled sacs within the lantern.

Question 6

Explain the physiology of lightning bugs BIOCHEMICALLY.

Answer 6

Luciferin is activated to Luciferyl-AMP using ATP, which produces photons when exposed to oxygen.

Question 7

Explain the physiology of lightning bugs MOLECULARLY.

Answer 7

Light cells in the lantern contain many mitochondria that consume O2 to make ATP. Without O2, Luciferyl-AMP cannot produce photons. The cell controls the release of nitric oxide, which naturally inhibits the mitochondria to allow the O2 reaction to produce photons.

Question 8

Explain the physiology of lightning bugs BEHAVIORALLY.

Answer 8

Mate attraction
Identification