Exam 39: Animal Form and Function

Many types of ectothermic animals can be seen lying out in the sun on a warm, sunny day. What is the primary mechanism by which the animal warms itself during this activity?

After you eat a meal, blood glucose concentration increases. Insulin is released from the pancreas to restore blood glucose concentration by facilitating the uptake of glucose by cells and stimulating the conversion of glucose to glycogen. What homeostatic mechanism is this an example of?

Which of the following is an example of a structure that has an increased surface area for absorption?

Which of the following explanations for brown adipose tissue explains why infant humans and some small mammals have this tissue type?

Natural selection has contributed to the wide variety of beak morphologies exhibited by the Galápagos Island finches. A correlation exists whereby beak morphology suggests the primary food source of the finch. Which physiological response listed below best describes the variety of beak morphologies seen in these finches?

Scientists have performed studies to show that having a fever is adaptive. Which of the following observations in an ectotherm would be consistent with this conclusion?

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by which mechanism?

Torpor has evolved in several high- latitude species even though it is energetically expensive. Why does this adaptation require a large energy input for those species that utilize this function?

Which class of tissue has many different types and functions in humans dictated by the unique extracellular matrix surrounding that tissue?

You begin exercising vigorously. This will, in a short time, cause your blood pH to begin dropping due to the release of carbon dioxide into your bloodstream. Which component of your homeostatic feedback system is responsible for deciding if your blood pH is far enough from normal that a response is necessary?

Your professor announces he has discovered a new species of bird that feeds mostly on worms and soft- bodied insects picked up from the ground and off of leaves. Based on this information, what shape of beak would you predict for this bird?

Which term best describes an animal that, although generating a significant amount of heat through metabolism, nonetheless does not maintain a constant body temperature?

Use the following information when answering the question below. The crucian carp Carassius carassius) is a Northern European freshwater fish often inhabiting ponds that become hypoxic hav reduced oxygen levels) and even anoxic have no oxygen) when the surface freezes during the winter. Surprisingly, when oxygen levels are normal, these fish lack the lamellae that provide a large surface area for gas exchange between water and blood: their gills are smooth. Yet when the level of oxygen in the water falls, the gill morphology undergoes a change: packing cells stop dividing and programmed cell death is induced, exposing gill lamellae that were buried in other tissue. With lamellae exposed, the gills have increased surface area for gas exchange. These changes in gill lamellar profile are reversible: investigators observed that the gills return to their normal structure within 7 days after returning the fish to well- oxygenated water. Jørund Sollid, Paula De Angelis, Kristian Gundersen, and Göran E. Nilsson. 2003. Hypoxia induces adaptive and reversible gross morphological changes in crucian carp gills. Journal of Experimental Biology 206:3667- 73.) -Gills serve multiple functions in fish in addition to gas exchange. Given the large surface area of gills with lamellae, what is the most likely explanation for why crucian carp cover protruding lamellae in their gills when levels of oxygen are normal?

Which of the following is not a function of an effector in the homeostatic regulation of temperature in mammals?

Wading birds in northern climates are able to walk in pools of water on ice without dying of hypothermia because they have countercurrent heat exchangers in their legs. These exchangers allow heat in warm blood going to the feet to be transferred to cool blood returning from the feet. Why are such countercurrent heat exchangers so efficient at conserving heat?

Salmon are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In freshwater, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?

A behavioural physiologist is studying the homeostatic control of blood pH. In a trial, a lizard runs on a treadmill for a set amount of time and the blood pH is measured. The blood pH drops as carbon dioxide is released into the bloodstream. Which component of the homeostatic feedback system is responsible for determining whether the blood pH is far enough from normal that a response is necessary?