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Exam 3
Mammalogy
12 December 2002
Name__________________________________
1. (10 pts) Your friend Joe has been watching too much TV again. He tells you that the
long neck of giraffes is to allow them to walk across the bottoms of rivers with just
their head sticking out!
Remember, Joe has a limited attention span, so be concise and limit your explanations
to less than 3 sentences.
Explain to Joe
a) Why this is a physically challenging undertaking for the giraffe:
b) The consequence for the giraffe’s anatomy:
________________________________________________.
c) tell him the only animal known to snorkel: __________________________
d) The proposed mechanism that allows snorkeling
__________________________________________________________.
e) How do diving mammals such as the Wedell seal avoid this problem?
2. (6 pts) Ansiogamy significantly impacts many aspects of mammalian life.
a) What is anisogamy?
b ) what sort of a mating system is favored by anisogamy and common in most
mammals?
3. (14 pts) Answer the following questions based on the figure below describing the
echolocation calls of a bat.
a) Label one of the pulses that is “frequency modulated” with “FM”. What are FM
calls useful for?
b) Explain in a few sentences, why the call structure changes at the spot indicated by
the arrow and what the bat is doing after this point.
c) What property of the echo does the bat use to detect whether the prey is moving
towards or away from the bat? _____________________________
d) What is the physiological conflict that bats confront in echo location?
e) List a way that bats solve the conflict.
f) Why does this problem exist?
g) Why is there less of such a conflict for marine mammals that echolocate?
4. (14 pts) Use the figures below to answer the following questions:
a) In female mammals, elevated levels of FSH and LH are responsible for
_____________________.
b) The uterine cycle is the process of
______________________________________
and is governed by which 2 hormones:
__________________
________________________
c) Which 2 hormones are essential for spermatogenesis?
___________________
______________________
d) POTENTIALY A TRUE STORY: you are a graduate student studying the
reproductive behavior of voles on the shores of the Great Salt Lake. You find
that the voles have DIOXIN, a common pollutant produced by companies like
Magna Corp, in their blood. You look up the effects of DIOXIN and find that
it called an “Estrogen Mimic” because it has the same effect as estrogen on
the mammalian reproductive cycle. Given the levels of DIOXIN found in the
voles (Plotted on the graph above), do you expect
INCREASED or DECREASED (circle one) reproductive output
Why?
5. ( 12 pts) Reproduction is energetically expensive for female mammals. The figure
below illustrates the amount of time 3 different female mammals spend in gestation
(or incubation) and lactation of young. All 3 are the same body size.
a) Which produces the most precocial (least embryonic) offspring at birth? _______
b) Which species expends the greatest amount of energy? _______
b) Which species has a chorioallontoic placenta? _______
d) List one advantage of a choriovitelline placenta:
6. (16 pts) Elephants live in highly structured societies where individuals can have
relationships for up to 50 years. Baby elephants are cared for by the entire herd.
Babies can nurse from any lactating female in the herd and juvenile females often
guard and protect babies.
a) If the baby elephant and its nurse or caretaker elephant are related, this behavior
can be explained by what type of fitness: _________________________.
b) If the elephants not related, give the 3 conditions favor the evolution of this type
of behavior:
1.
2.
3.
What is this type of behavior called? ________________________________.
Elephants continued:
c) Many nature shows often say “social behavior evolves for the good of the
species”.
Is this statement is TRUE or FALSE (circle one).
d) A female elephant reproduced multiple times over the course of her life. What is
the term for this reproductive trait? ____________________________.
e) When elephants are removed from an area, the species diversity of plants and
animals changes drastically resulting in lower species diversity. From a
community ecology perspective an elephant would therefore be labeled a
_______________________________.
7. ( 6 pts) In the Class Aves (birds) the volant (flying) species have the longest
migratory routes. Why is this not true in the Class Mammalia?
Which mammalian species has the longest migration? ______________________
8. (6 pts) Red squirrels forage almost exclusively on pinecones and also store many
cones for future consumption.
a) If the squirrel decreases the fitness of the pine tree from which it collects cones,
the symbiosis (relationship) between the squirrel and pine tree is
called ___________________________.
b) However, sometimes the fitness of the pine trees are increased because the
squirrel does not consume all the cones it collects and the transportation of the
cone to the cache puts the seeds in more favorable microhabitat than under the
mother tree.
In this case the relationship is called _________________________.
9. (10 pts)You set out to test the limiting similarities hypothesis with a community of
bats in a tropical forest. You get the following results for body size for 5 species of
bats:
SPECIES
hairy
yellow
Spotted
Rhino face
Big-Ugly
Average Body
mass (g)
8
17
23
37
75
a) The data for which species support the hypothesis?
Why? (one sentence)
b) In several other more disturbed habitats, you find only 2 species, Yellow and BigUgly. In these situations, the body size of Yellow is on average 25 g and the body
size of Big-Ugly is 75. Big-Ugly occurs over a much broader elevational gradient
in the disturbed habitats compared to the more species diverse community.
Give the NUMBERS of all the TRUE statements:______________________
1)
2)
3)
4)
Yellow has undergone competitive release in the disturbed habitats.
Big-Ugly is an example of character displacement.
Yellow is an example of character displacement.
Big-Ugly has undergone competitive release in the disturbed habitats.
c) True or false: Competition is the predominant force structuring communitites.
9) (16 pts) These figures shows initial, intermediate and current arrangements in
the evolution of an offshore island system. The current distribution of one clade
of rodents (a-f) is shown in figure 4.
Time
Sequence: 1 is the most ancient, 5 is the current.
a) Assuming that there has been only one colonization event for this group from the
mainland and no subsequent colonizations between islands, draw a cladogram that
describes the probable evolutionary relationships of the 6 species.
b) For all of the mammal species occurring in this system and allowing for both
colonization and local extinction, draw the expected species-area lines for (A) nonflying mammals and (B) bats.
c) Of the five current islands, which is likely to have the lowest rates of population
extinction, and why?
d) Each species of mammal has its own unique species of blood-sucking louse. What
process may this be an example of? ____________________________________.
e) Give 2 circumstances under which the direct mortality of the mammal host by the
louse would be favored by natural selection: