Directions: Read the following article and answer the associated questions. Each question is worth .5 point unless otherwise
noted. Total: 25 points
Please NOTE: If the following link does not open, the pdf for this article is attached within the same folder as this exercise.
http://www.adaptt.org/documents/Mills%20The%20Comparative%20Anatomy%20of%20Eating1.pdf
Oral Cavity:
1. Carnivores have a ___wide_____________mouth opening in relation to their head size.
2. Facial musculature is ___reduced_______________ in carnivores.
3. The primary muscle use in the operation of the jaw in carnivores is the _temporalis
muscle___________
4. The lower jaw of carnivores cannot do what?
The lower jaw of carnivores cannot move forward and has limited side-to-side motion.
5. The teeth of a carnivore are discreetly spaced in order to not _trap stringy
debirs___________
6. The molars of carnivores are triangular with jagged edges that function like
_serrated-edged blades_______
7. The saliva of carnivores does not contain__digestive________ ____enzymes______
8. Carnivores do not mix their food with saliva. They simply bite off huge chunks and
swallow them ___whole______
9. Herbivore mammals have _____well-developed____________ facial musculature, fleshy
__lips______ and a relatively __small__________ opening into the oral cavity
10. The masseter muscle in herbivores is not well developed True or false?
11. The lower jaw of plant eating animals has a pronounced __sideways______ to
_________ , motion when eating.
12. Canines in herbivores are thought to be used for what purpose?
Canines in herbivores are thought to be used for eating purposes.
13. The molars of herbivores are squared and flattened to provide a ___grinding______
surface.
14. The saliva of plant eating animals often contains __carbohydrate____________
digestive enzymes
Stomach and Small Intestine:
1. Carnivores have a ___single______ - __chambered_____stomach
2. The stomach chamber represents __60-70_______% of the total capacity of the
digestive system.
3. Small intestines in carnivores are __short and 151__________. (____3____- 5 times
the body length)
The Comparative Anatomy of Eating
4. A large stomach size is advantageous to carnivores because it allows animals to
____quickly gorge themselves when eating_____________________________
5. What are two functions of the low pH resulting in the secretion of Hydrochloric acid in
carnivores?
Two functions of the low pH resulting in the secretion of Hydrochloric acid in carnivores
is to facilitate protein breakdown and kill an abundance of bacteria that is found in
decaying flesh foods.
6. Why do herbivores have longer and more elaborate guts than carnivores?
Herbivores have longer and more elaborate guts than carnivores due to the relative
difficulty with various kinds of plant foods that are broken down, these plants have large
amounts of indigestible fibers.
7. What is another word for "digest by bacterial action"?
Another word for “digest by bacterial action” is ferment.
8. What is another word for "foregut fermenters"?
Another word for “foregut fermenters” is ruminants.
9. Why would a multiple stomach fermentation process be energetically wasteful in an
animal that consumed a soft, pulpy vegetation?
Multiple stomach fermentation processes may be energetically wasteful in an animal
that consumed a soft, pulpy vegetation because they use carbohydrate-digesting
enzymes in their saliva, which only requires a simple stomach.
10. The small intestine of plant eaters tend to be very __long______ (___10___times the
body length) Why? This allows them to have sufficient time and space for absorption of
the nutrients.
Colon
1. The only purpose of the colon in carnivores is to absorb __salt_______ and
_____water______.
2. In herbivores the colon tends to be a highly __specialized____ Organ
3. What are the three functions of the colon in herbivores?
The three functions of the colon in herbivores are water and electrolyte absorption,
vitamin production and absorption, and/or fermentation of fibrous plant materials.
Omnivore
1. An Omnivore is basically a carnivore with some gastrointestinal adpations for eating
plants. True or false?
2. Bears digest fibrous material very well. True or false?
3. Why do many scientists believe bears (not polar bears) hibernate in the winter?
Scientists believe that bears hibernate in the winter because the primary source of food,
succulent vegetation, is not available in the cold northern winters.
4. In bears, what is the most prominent adaptation to an herbivores diet?
The most prominent adaptation to an herbivore diet is the modification of their
dentition.
5. Why would an herbivore style jaw not suit a bear well?
A herbivore style jaw would not suit a bear well because a bear requires a jaw that
allows them to kill and dismember their prey, and an herbivore jaw is easily dislocated
and would not be able to withstand the amount of stress that comes with handling a
caught prey.
Humans
1. The human gastrointestinal tract features the anatomical modifications consistent with
what type of diet?
Human gastrointestinal tract features anatomical modification consistent with a
herbivorous diet.
2. Many of the "Muscles of expression" are actually used in __chewing________________.
3. The muscular and agile tongue essential for eating, has adapted to use in ___speech and
other things________.
4. The temporalis muscle in humans is ____reduced______
5. The human mandible can move in what manner?
The human mandible can move forward and side-to-side.
6. The pre-molars and molars in humans are used for __crushing, grinding and pulping non
coarse foods_____________
7. Human saliva contains ___carbohydrate_____digesting enzymes.
8. Although man's stomach is single chambers it is only __moderately______ acidic.
9. The human small intestine is 10-11____times the body length).
10. The human colon, like herbivores, serves three functions. What are they?
The three functions of the human colon are water and electrolyte absorption, vitamin
production and absorption, and extensive bacterial fermentation of fibrous plant
materials.
Discussion: Write a short paragraph describing the type of diet you believe humans have
evolved to consume and why…..
(4 points)
Humans have evolved to consume omnivorous diet. Based on the reading humans have many similar
attributes that a herbivore contains but they also have similar features with carnivores. In the
summary of the article, there are many similarities in the way a herbivore is to a human. For example,
the herbivore and humans have an expanded jaw angle. Additionally, both have identical jaw joint
location, joint motion, major jaw muscles and teeth. However, they do have some differences and I
think that has to do with the fact that humans also have evolved to eat meat which required them to
obtain different features than herbivores to properly digest/eat meat. Overall, humans have evolved
to consume an omnivorous diet because of environmental changes and the variety of food that was
available to them, which can be seen now as well.
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