Mammalogy
Spring 1998
Exam 1 Name ______________________________

I. Multiple choice. Choose the single best answer. (3 points each)
  1. What variation on the usual mammalian reproductive pattern is associated with exposure to strange, potentially infanticidal males during pregnancy?
    1. delayed fertilization
    2. delayed implantation
    3. spontaneous abortion
    4. altricial young

  2. Which of the following morphological characteristics is related to a fossorial lifestyle?
    1. the platypus's beak
    2. marsupium opening posteriorly
    3. the echidna's spines
    4. epipubic bones

  3. What has NOT been proposed as a reason for the apparent competitive disadvantage of marsupials relative to eutherians?
    1. smaller number of chromosomes
    2. mode of reproduction
    3. small cerebral cortex
    4. low energy requirements during reproduction

  4. What sense does the platypus use while foraging?
    1. sight
    2. hearing
    3. electroreception
    4. smell

  5. Which ovarian hormone exerts negative feedback on the hypothalamus/pituitary gland, thereby suppressing follicle development and maintaining pregnancy?
    1. progesterone
    2. luteinizing hormone
    3. estrogen
    4. follicle stimulating hormone

  6. Who devised the Latin-based system of nomenclature that is used world-wide today?
    1. John Ray
    2. Linnaeus
    3. George Simpson
    4. Elaine Pincus

  7. A zebra's whiskers are ___________, while a zebra's mane is ____________ .
    1. angora growth, definitive growth
    2. fur, angora growth
    3. velli, wool
    4. vibrissae, bristles

  8. Which of these male reproductive structures is likely to be very complex in species with induced ovulation?
    1. vesicular gland
    2. baculum
    3. urethra
    4. external scrotum

  9. Multituberculates are notable because they
    1. are among the earliest mammals known
    2. existed for a longer time span than any other mammalian group
    3. had oddly-shaped cheek teeth
    4. all of the above

  10. The Prototheria differ from all other living Subclasses of mammals in that they
    1. lay eggs
    2. are extinct
    3. have primitive placentas and give birth to highly undeveloped young
    4. have embryonic diapause

    II. Matching.

    Match each characteristics with the most appropriate answer from the answer set below. Each answer can be used more than once, but there is only one correct answer for each characteristics (14 points).

    1. Found ONLY in present day mammals and in ALL species of present day mammals
    2. Found in ALL present-day mammals, but also in some present-day non-mammals
    3. Found ONLY in present-day mammals, but not in all species of present-day mammals
    4. NOT found in present-day mammals

    _____ more than two complete sets of teeth
    _____ mammary glands in female
    _____ sweat glands
    _____ dentary-squamosal joint
    _____ quadrate
    _____ auditory bullae
    _____ hair
    _____ 4-chambered heart
    _____ gills in adults
    _____ ossicles
    _____ enucleate erythrocytes
    _____ homeothermy
    _____ pinnae
    _____ feathers

    Select the best explanation for each phenomenon from the answer set below. Each answer may be used only once (7 points).

    1. pheomelanin
    2. eumelanin
    3. alternating bands of pheomelanin and eumelanin
    4. absence of eumelanin and pheomelanin
    5. counter shading
    6. spines
    7. molting

    _____ raccoon eyes stripes
    _____ defense against predators
    _____ agouti coloration
    _____ dark on dorsal surface, lighter on ventrum
    _____ seasonal color change
    _____ white hair
    _____ red coat of an Irish Setter

    Short answer (5 points each).
    1. Describe the developmental state of marsupials at birth. What hypothesis discussed in class attempts to explain why marsupials are born in such a state?
    1. Compare and contrast the anatomy of the female reproductive systems of the Monotremata and the Marsupialia. You may draw a diagram, if you wish.
    1. What is heterodont dentition? Describe the four types of mammalian teeth in terms of their shape and function.
    1. Which family of marsupials has a chorioallantoic placenta? What type of placenta do other families of marsupials have? How do the two types differ with respect to the amount and type of contact with the uterine lining of the female?
    1. Describe the two basic types of mammary glands found in Eutherian mammals. In what way does the mammary gland in the Monotremata differ?
    1. What is the role of the following structures in the development of homeothermy?

    heterodont dentition

    muscular diaphragm

    sweat glands

    enucleate erythrocytes

    sebaceous glands

    1. Shown below are the hind feet of marsupials of the family (a) Didelphidae, (b) Macropodidae and (c) Dasyuridae. Describe how the morphological specializations (syndactyly, opposable hallux, length of digits) of the feet relate to their mode of locomotion.
    1. (a) List 3 "mammalian" characteristics that were also present in therapsid reptiles. (b) List 3 ways in which the first mammals were distinct from therapsids. (c) Why might these early mammals have persisted, while the therapsids went extinct?
    1. Some early classification schemes used modes of locomotion to differentiate groups of mammals. Why is this not a satisfactory character for constructing phylogenies? Be sure to explain how convergence contributes to the problem. Name two other types of characters that are more useful. Is convergence still a problem with the other methods?