Essay (use lined paper, 2 pages max- sketches/tables don’t count toward the 2 page limit but lists and tables alone do not count as an essay!  You must discuss these issues.)


1 Compare and contrast gorillas and orangutans with respect to their sensory systems, limbs and locomotion, brain features, and social & reproductive structures and patterns. (6 points) 

Then discuss briefly the "synergy" among the various characteristics --that is how they fit together enabling adaptation to distinct niches. (2 points)

For each species, close with a distinct one sentence comparison with humans suggesting one feature that is most similar to humans. For example, if the comparison were about chimps and humans, you might say both species engage in group hunting . (2 points)

(Be sure to say something about each of these features for each of your primates; if they are not different on some dimension, say so. Then say how those features work together --the synergy-- to enable those species to "fit" well into their niches. (I think a niche originally meant a hole in the wall where birds could build a nest.

THIS IS MORE EASILY GRADED AS A 12 POINT QUESTION, THOUGH IT IS STILL WORTH ABOUT 1/3 OF EXAM.

GIVE 5X2 POINTS FOR COMPARISONS/CONTRASTS ON 5 DIMENSIONS (WHICH DIMENSIONS CAN BE SOMEWHAT FLEXIBLE SINCE SOCIAL/REPRODUCTIVE MIGHT BE SPLIT. OR LIMBS AND LOCOMOTION

GIVE 1 POINT FOR A SENSIBLE STATEMENT ABOUT SYNERGY AMONG DIMENSIONS FOR EACH SPECIES. (2 POINTS TOTAL)

GIVE 1 POINT FOR ANYTHING SENSIBLE ABOUT USING THESE SPECIES AS “MODELS” FOR EVOLUTION AND BEHAVIOR OF HUMANS, PRO OR CON.  SEE EXAMPLES BELOW. (1 POINT TOTAL)

HERE’S MY “TABLE” OF GORILLA VS ORANGUTAN (ORANG)

SEE "PRIMATE FAMILY" TOPIC NOTES FOR MORE INFO.

FEATURE/SPECIES

GORILLA (AFRICAN APE)

ORANG (ASIAN APE)

LOCOMOTION

TERRESTRIAL QUADRAPED (SMALLER ANIMALS CAN CLIMB SKILLFULLY; LITTLE JOE'S ESCAPE IS A CASE IN POINT.

ARBOREAL “WALKER”

SKILLFULLY USES 4 LIMBS TO GO FROM TREE TO TREE, USING WEIGHT TO SWING TREE OR BRANCH.

HINDLIMBS

REFLECT TERRESTRIAL ENVIRONMENT

VERY SIMILAR TO FORELIMBS TO GRASP BRANCHES WHILE “WALKING” IN TREE.

FORELIMBS

GRASPING HAND, THUMB

GRASPING HAND, USING 4 FINGERS, LITTLE THUMB INVOLVMENT

 

DESIGNED WITH SHOULDER FOR SWINGING

 

BRAIN

ABOUT 1/3 OR LESS SIZE OF HUMAN BRAIN; VARIABLE IN PROPORTION TO BODY WEIGHT.

BOTH SPECIES HAVE SIMILAR BRAIN "PLAN" WITH VERY MINOR DIFFERENCES.

SAME AS GORILLA , MAYBE A BIT LARGER RELATIVE TO BODY

SENSORY SYSTEMS

GORILLA AND ORANG VERY SIMILAR TO EACH OTHER

MINOR SPECIFIC ADAPTATIONS FOR HEARING LONG CALLS IN ARBOREAL ENVIRONMENT??

(DOMINANT MALE CALLS MAY STUNT GROWTH OF NEARBY YOUNG ADOLESCENT MALES.)

SOCIAL ORGANIZATION

SMALL FAMILY GROUPS WITH A DOMINANT SILVERBACK, A NUMBER OF MATURE FEMALES WITH THEIR INFANT AND JUVENILE OFFSPRING, ALMOST ALWAYS FATHERED BY THE SILVERBACK. ANY YOUNGER MATURE MALES USUALLY OFFSPRING OF SILVERBACK.

VERY UNIQUE SOLITARY LIFE. ONE DOMINANT MALE DRIVES OTHERS OUT OF TERRITORY THAT CONTAINS SEVERAL FEMALES WHO RARELY CONTACT MALE EXCEPT BY HIS LOUD CALLS.

FEMALE IS SOLITARY WITH 1 OR 2 OFFSPRING, 8 OR SO YEARS APART.

RARE EXCEPTIONS TO SOLITARY LIFE MAY OCCUR WHEN FRUIT IS PLENTIFUL

SEX/REPRODUCTION

BOTH FOLLOW TYPICAL PRIMATE PATTERN- EXTENSIVE CARE FOR DEPENDENT SINGLETON OFFSPRING BY MOM.

 

GORILLA & ORANG MALES MAY BE TWICE SIZE OF FEMALES DUE TO MALES' COMPETING WITH EACH OTHER FOR DOMINANCE OF LOCAL FEMALES. UNLIKE CHIMPS AND SOME MONKEYS, THESE TWO SPECIES HAVE A "WINNER TAKE ALL" PROCESS.

MALE GORILLAS MAY BE INVOLVED IN THEIR OFFSPRING CARE

IN BOTH SPECIES, M & F OFFSPRING LEAVE MOTHER. FEMALES SOLICIT SEX FROM SILVERBACK WHEN IN ESTROUS, MAYBE EVERY 3 OR 4 YEARS. FEMALES MAY ONLY HAVE 3-5 OFFSPRING .

ORANG MALE NEVER INTERACTS WITH HIS OFFSPRING; VERY LOW MPI* OTHER THAN PROTECTION FROM OUTSIDE MALES LOOKING FOR FEMALES. THESE MALES MAY ATTEMPT FORCED COPULATION WITH SMALLER FEMALES.

ORANG FEMALES HAVE LITTLE OBSERVABLE SWELLINGS WHEN FERTILE BUT SEEK DOMINANT MALE EVERY 6-8 YEARS AND MAY HAVE ONLY 3 OR 4 OFFSPRING

 (DIET) FOR BOTH SPECIES DETERMINES SOCIAL BEHAVIOR TO EXTENT

PRIMARILY TERRESTRIAL VEGETARIAN; LEAVES, GRASS, BARK, WOOD, SOME INSECTS.

 

LITTLE NEED FOR GROUPS TO FORAGE WIDELY FOR PREFERRED FOODS.

 

ARBOREAL FRUIT PRIMARILY, BARK, SEEDS, INSECTS, HONEY

 

INDIVIDUALS FORAGE OVER WIDE RANGE

HUMAN MODEL?

 GORILLA POYGENOUS SOCIETY SIMILAR TO MANY HUMAN CULTURES .

 

GORILLAS OFTEN CONSIDERED SLIGHTLY LESS BRIGHT THAN ORANGS OR CHIMPS.

ARBOREAL ENVIRONMENT MAY BE SIMILAR TO OUR VERY OLD PRIMATE ANCESTORS, BIPEDALISM MAY HAVE BEEN ENABLED FROM THE UPRIGHT WALKING POSITION IN TREES. (The foramen magnum location.)

ORANG COGNITION IS VERY GOOD AND SERVES AS COMPARISON IN HUMAN EVOLUTION RESEARCH

1. ALL PRIMATES HAVE A SYNERGISTIC COLLECTION OF FEATURES INVOLVING BIGGER BRAINS, HIGH MATERNAL CARE, LONGER PERIODS OF MATURATION.. ETC.  ANYTHING REASONABLE . SPECIFICALLY ONE MIGHT NOTE THE GORILLA'S FEET AND FOOD CHOICES ARE TERRESTRIAL ADAPTATIONS. ORANG FEET AND FOOD PREFERENCES ARE ARBOREAL ADAPTATIONS.

2. BOTH SPECIES HAVE BEEN USED AS MODELS FOR HUMAN EVOLUTION, BIOLOGY, AND PSYCHOLOGY.

*MPI ABREVIATES  “MALE PARENTAL INVESTMENT”  which is very high for humans and low for most apes, ESPECIALLY ORANGUATAN MALES.

comments on short & essay answers:

1. Give enough details; use the page limits to impress the graders with your organization and details.  If you want an A or B, you need details and few if any mistakes.

2. Don’t confuse readers with “they reproduce every 2 years” when it isn’t clear who they refers to!

3.  It is often in grading essays that the best essays were accompanied by a table similar to the above—maybe everyone ought to follow that procedure?

4. Don’t try to stay within two pages by writing very tiny letters. We  need to read accurately to grade accurately.

 

5. And of course you need to address—answer—all of the parts of the question.  For example on the essay some people didn’t even mention the brain and sensory systems in their essay.  You are down at least two or more points from the start.  Even one sentence—“Both gorilla and orangutan have relatively large brains for primates, about 1/3 the size of a human brain.” will do.  I’m not looking for arcane facts about differences in cells, overall shape, brain region functions etc.  If you know some, fine, impress the graders.