J. S. Hart (Can. J. Zool. (1956) 34, 1, pp. 53-57) described seasonal changes in insulation of the fur of nine species of arctic and North temperate zone mammals. Relative seasonal changes ranged from 12 to 52% of the winter coat insulation value. Absolute changes were greatest in the largest mammals with thickest fur. Indicate if the following statements that are true or false. a. Increasing fur thickness would reduce conduction between the animal and the environment True or Falseb. Animals with thicker fur compared to those with thinner fur have different metabolic rates when measured at the same ambient temperature below the thermal neutral zone (TNZ). True or falsec. Endothermic mammals are most often classified as homeotherms. True or falsed. Fur does not affect the rate of convective and conductive heat loss in the cold. True or falsee. Changes in fur thickness is associated with an expression of a unique phenotype that optimizes fitness for a given environmental temperature. True or false

a. True

b. True

c. True

d. False

e. True

Explanation:

The fur plays a critical role as an insulator and it may be a greater thickness during the winter. The fur allows the animals to reduce their heat loss, thereby thicker fur may serve as an additional layer of insulation during the winter. Endothermic animals such as birds and mammals are capable of maintaining a constant body temperature independent of the environmental conditions. In a similar way, the homeothermic animals are able to maintain stable body temperature by regulating their metabolic processes (i.e., also mammals and birds can be classified as homeothermic animals). The study above cited (Hart, 1956) was aimed at collecting comparative information to support the role of fur as insulation in Canadian mammals and thus understand seasonal acclimatization in general. In this regard, Hart concluded that although seasonal differences could be observed in all species analyzed, the greatest absolute changes were observed in larger animals (that is, animals having the thickest fur).

1. is geographic distribution

2 is increasing complexity

3 is transitional forms