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					                       Anatomy Summer Homework
                      Gamble Montessori High School
                             Summer- 2010


1. Disease Research- Due August 6th, 2010

   Objective: To conduct preliminary research you can use for a project on a
   disease, syndrome, or condition you will complete during first semester.

   Procedures:

   1. Find three diseases, syndromes, or conditions you could possibly conduct a
      report on.


   2. Using printed or online resources, find the following information about each
      of the three diseases:

          A.   Name
          B.   Symptoms
          C.   Who is affected?
          D.   Is it genetic?
          E.   How is it treated?


   3. Write a short report (1-2 pages) for each disease that gives the above
      information. Cite what references you used at the end of the report.


2. Seminar Preparation- “Human are Omnivores”

   Objective: Prepare for a seminar on the above article.

   Procedures:

   1. Read and annotate the article using the following guiding questions:

          A. What evidence suggests humans are herbivores?
          B. What evidence suggests humans are omnivores?
          C. What characteristics do humans share with other primates?

   2. Write five questions of your own about the article.

   3. Have annotations checked the first day of school and be prepared for
      seminar on the second day of school.
Humans are Omnivores
Introduction

There are a number of popular myths about vegetarianism that have no scientific basis in
fact. One of these myths is that man is naturally a vegetarian because our bodies
resemble plant eaters, not carnivores. In fact we are omnivores, capable of either eating
meat or plant foods. The following addresses the unscientific theory of man being only a
plant eater.

Confusion between Taxonomy and Diet

Much of the misinformation on the issue of man's being a natural vegetarian arises from
confusion between taxonomic (in biology, the procedure of classifying organisms in
established categories) and dietary characteristics.

Members of the mammalian Order Carnivora may or may not be exclusive meat eaters.
Those which eat only meat are carnivores. Dietary adaptations are not limited by a
simple dichotomy between herbivores (strict vegetarians) and carnivores (strict meat-
eaters), but include frugivores (predominantly fruit), gramnivores (nuts, seeds, etc.),
folivores (leaves), insectivores (carnivore-insects and small vertebrates), etc. Is is also
important to remember that the relation between the form (anatomy/physiology) and
function (behavior) is not always one to one. Individual anatomical structures can serve
one or more functions and similar functions can be served by several forms.

Omnivorism

The key category in the discussion of human diet is omnivores, which are defined as
generalized feeders, with neither carnivore nor herbivore specializations for acquiring or
processing food, and who are capable of consuming and do consume both animal protein
and vegetation. They are basically *opportunistic* feeders (survive by eating what is
available) with more generalized anatomical and physiological traits, especially the
dentition (teeth). All the available evidence indicates that the natural human diet is
omnivorous and would include meat. We are not, however, required to consume animal
protein. We have a choice.

The Great Apes

There are very few frugivores amongst the mammals in general, and primates in
particular. The only apes that are predominantly fruit eaters (gibbons and siamangs) are
atypical for apes in many behavioral and ecological respects and eat substantial amounts
of vegetation. Orangutans are similar, with no observations in the wild of eating meat.

Gorillas are more typically vegetarian, with less emphasis on fruit. Several years ago a
very elegant study was done on the relationship between body size and diet in primates
(and some other mammal groups). The only primates on the list with pure diets were the
very small species (which are entirely insectivorous) and the largest (which specialize in
vegetarian diet). However, the spectrum of dietary preferences reflect the daily food
intake needs of each body size and the relative availability of food resources in a tropical
forest. Our closest relatives among the apes are the chimpanzees (i.e., anatomically,
behaviorally, genetically, and evolutionarily), who frequently kill and eat other mammals
(including other primates).

Evidence of Humans as Omnivores

Archeological Record

As far back as it can be traced, clearly the archeological record indicates an omnivorous
diet for humans that included meat. Our ancestry is among the hunter/gatherers from
the beginning. Once domestication of food sources began, it included both animals and
plants.

Cell Types

Relative number and distribution of cell types, as well as structural specializations, are
more important than overall length of the intestine to determining a typical diet. Dogs
are typical carnivores, but their intestinal characteristics have more in common with
omnivores. Wolves eat quite a lot of plant material.

Fermenting Vats

Nearly all plant eaters have fermenting vats (enlarged chambers where foods sits and
microbes attack it). Ruminants like cattle and deer have forward sacs derived from
remodeled esophagus and stomach. Horses, rhinos, and colobine monkeys have
posterior, hindgut sacs. Humans have no such specializations.

Jaws

Although evidence on the structure and function of human hands and jaws, behavior,
and evolutionary history also either support an omnivorous diet or fail to support strict
vegetarianism, the best evidence comes from our teeth.

The short canines in humans are a functional consequence of the enlarged cranium and
associated reduction of the size of the jaws. In primates, canines function as both defense
weapons and visual threat devices. Interestingly, the primates with the largest canines
(gorillas and gelada baboons) both have basically vegetarian diets. In archeological sites,
broken human molars are most often confused with broken premolars and molars of
pigs, a classic omnivore. On the other hand, some herbivores have well-developed
incisors that are often mistaken for those of human teeth when found in archeological
excavations.

Salivary Glands

These indicate we could be omnivores. Saliva and urine data vary, depending on diet, not
taxonomic group.

Intestines

Intestinal absorption is a surface area, not linear problem. Dogs (which are carnivores)
have intestinal specializations more characteristic of omnivores than carnivores such as
cats. The relative number of crypts and cell types is a better indication of diet than
simple length. We are intermediate between the two groups.

Conclusion

Humans are classic examples of omnivores in all relevant anatomical traits. There is no
basis in anatomy or physiology for the assumption that humans are pre-adapted to the
vegetarian diet. For that reason, the best arguments in support of a meat-free diet
remain ecological, ethical, and health concerns.

[Dr. McArdle is a vegetarian and currently Scientific Advisor to The American Anti-
Vivisection Society. He is an anatomist and a primatologist.]



Source: The Vegetarian Resource Group.

				
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