Claytonia virginica is a woodland spring herb with flowers that vary from white, to pale pink, to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?

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#Question id: 16121

#Unit 7. System Physiology – Animal

 Match the following mechanisms (Column I) with their correct example (Column II).

Column I	Column II
A. Heat-generating and heat-retaining mechanisms	i. increased metabolic rate (thyroid hormones, sympathetic nervous system)
B. Heat-dissipating mechanisms	ii. vasodilation of blood vessels of the skin (decreased sympathetic tone)
	iii. increased activity of sympathetic cholinergic fibers to sweat glands.
	iv. shivering
	v. vasoconstriction of blood vessels of the skin (increased sympathetic tone)

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#Question id: 16120

#Unit 7. System Physiology – Animal

Following statements are regarding to the regulation of body temperature.

A. The temperature-regulating center is located in the anterior hypothalamus. This center receives information about environmental temperature from thermoreceptors in the skin and about core temperature from thermoreceptors in the anterior hypothalamus itself.

B. The temperature-regulating center is located in the posterior hypothalamus. This center receives information about environmental temperature from thermoreceptors in the posterior hypothalamus itself and about core temperature from thermoreceptors in the skin.

C. If core temperature is below the set-point temperature, then heat-generating and heat-retaining mechanisms are activated.

D. If core temperature is above the set-point temperature, then heat-dissipating mechanisms are activated.

E. If core temperature is below the set-point temperature, then heat-dissipating mechanisms are activated.

F. If core temperature is above the set-point temperature, then heat-generating and heat-retaining mechanisms are activated.

Which of the following combination is correct?

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#Question id: 16119

#Unit 7. System Physiology – Animal

Following statements are regarding to Shivering, which is the most potent mechanism for increasing heat production in the body. 

A. Cold environmental temperatures activate centers in the posterior hypothalamus during shivering, which then activate the α and γ motoneurons innervating skeletal muscle. 

B. Shivering involves skeletal muscle contracts rhythmically, generating heat and raising body temperature.

C. Shivering involves stimulation of Na+-K+ ATPase and raising body temperature.

D. Shivering involves stimulation of β receptors in brown fat, which increases metabolic rate and heat production.

Which of the following combination is correct?

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#Question id: 16117

#Unit 7. System Physiology – Animal

Thyroid hormones are thermogenic, their actions on target tissues result in heat production by following mechanisms:

i. stimulation of Na+-K+ ATPase

ii. increased O2 consumption

iii. increased metabolic rate

iv. increase in the number and activity of mitochondria

which of the following combinations are correct regarding heat production?

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#Question id: 11475

#Unit 7. System Physiology – Animal

Rods exposed to light will ________.

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#Question id: 11664

#Unit 7. System Physiology – Animal

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?