BBio 352: QUIZ / April 22, 2015
NAME: ______Dr. C._________________________
1. What can you conclude or guess about the animal whose skull and teeth are shown below?
(Herbivore or carnivore? Mammal or non-mammal?) Briefly explain your reasoning. If you are
not positive about a particular feature, explain what you THINK you see.
The animal is (or was) a carnivore. The sharp teeth are good for slicing through meat, and the
jaw joint is in line with the upper row of teeth, consistent with force being focused at the front
teeth for subduing and cutting into prey.
The animal is not a mammal. (Some of you correctly identified it as an alligator or crocodile.)
Mammals have a great variety of teeth that fit together exactly (precise occlusion) in order to
chew their food more fully (to support their high metabolic rates). Some of you thought the
teeth looked rather varied, and it’s OK if you suspected the animal was a mammal because of
this, but notice that no molars or molar-like teeth are present. One of you (Summer) made the
insightful observation that the variations in tooth size and sharpness suggested that they had
been frequently replaced at different times, as opposed to mammals’ highly infrequent
replacement.
2. What can you conclude about the digestive system shown at left? (Ruminant or nonruminant? Small or large animal?) Briefly explain.
For its size, this animal has a relatively simple stomach and a relatively long large intestine,
suggesting that it is a large non-ruminant. (It is an African elephant.) Small non-ruminants tend
to have a more prominent cecum. (It is OK if you had trouble distinguishing the cecum from the
large intestine, thought the cecum was large, and concluded the animal was small.) Some of
you also noticed that, according to the scale provided, the digestive tract is quite long when
stretched out, and should belong to a large animal.
3. What is a hydrodynamic tongue, and who/what has one or would be expected to have one?
A hydrodynamic tongue is not the same thing as a hydrostatic tongue – some of you seemed
confused on this point. It is the use of water to move food back in the mouth as the muscular
tongue of a terrestrial animal would normally do. The example we saw was of a mudskipper, a
fish that feeds on land, carrying water in its mouth, spitting it out and then sucking it back in as
a way of capturing prey. Thus, while rare, the hydrodynamic tongue could be expected to be
found in some aquatic animals that feed on land.
4. Protists, sponges, and some cnidarians (e.g., jellyfish) are unusual among animals in that their
digestion of food
a. is incredibly slow
b. is intracellular
c. is solely nocturnal
d. is started in a basic (pH > 7) stomach
e. is started in a multi-part stomach
5. Highly specialized suction feeders should have
a. large mouths and highly kinetic jaws
b. large mouths and jaws with limited movement
c. small mouths and highly kinetic jaws
d. small mouths and jaws with limited movement
e. no mouths and no jaws
6. How do ruminants differ from non-ruminants?
a. Only ruminants can digest cellulose.
b. Only ruminants have microorganisms residing within their digestive tract.
c. Only ruminants have a complex stomach specialized for hosting microbes.
d. Only ruminants sometimes engage in coprophagy.
e. all of the above
[C was the answer I was looking for, but I decided that A was difficult to rule out based on what
was said in class, and therefore someone might want to put A – or E, if both A and C were both
thought true…. In the end I accepted A, C, or E.]
7. An area of the digestive tract that is especially prominent in small non-ruminants is the
a. esophagus
b. stomach
c. small intestine [I only took off 1 point for this answer because it is not a terrible answer; one
might reason that non-ruminants don’t absorb any nutrients in the stomach and thus must
have a longer small intestine to absorb more nutrients there]
d. cecum
e. large intestine
8. Most animals cannot themselves extract energy from cellulose because
a. very little chemical energy is stored in cellulose
b. most animals tend not to eat cellulose
c. most animals lack enzymes to break bonds between sugar groups
d. most animals lack enzymes to break the specific type of bond found in cellulose
e. a toxic product results from the breakdown of cellulose