1. Two organisms in the same family have more structural characteristics in common than two organisms in the same class.
Family is a more specific level of classification than class.

2. Two words make up the species name of an organism.

The first word is the name of the genus and starts with a capital.
The second word is the name of the species and is all in lower case.
If the name is in writing, it should be underlined.
For example, Cercopithecus aethiops.
If the name is typed or printed, it should be in italics.
For example: Homo sapiens.
The species name does not change it spelling for singular or plural.
The species name is usually Latin or Latinised Greek, or Latinised English. etc.

3. No, it is not possible for two animals to be in the same genus but not in the same family.

Reason: Genus is a more specific level of classification than family.
Two members of the same genus must belong to the same family,
the same order, the same class, the same phylum and the same kingdom.

4. No, the baboon and mandrill do not belong to the same species.

They do belong to the same genus (Papio)
but they have different specific names (papio and sphinx),
so they are in different species.

Revision Questions

The primate hand has many important features.

1. Nails have replaced claws on the digits of primates to enable opposable digits to come closer
together, allowing for more efficient grasping. (0.5 mark)
Nails give better support, acting as a solid backing behind the friction-ridged pads of the fingers,
allowing for more efficient grasping. (0.5 mark)

2. Friction ridges (aka fingerprints) would be an advantage to an arboreal primate as they increase the
friction, thereby improving the grip for grasping branches. (1 mark)

For terrestrial primates, fingerprints would improve the grip for manipulating objects. (1 mark)

3. The absence of hair from primate hands increases the sensitivity, as hair would interfere with the
functioning of the receptors and the fingerprints. (0.5 mark)

Hair is slippery. The presence of hair would decrease the grip for the prehensile hand
and would decrease the grip for the manipulative hand. (0.5 mark)

4. The term “prehensile” or “prehensibility” is used to describe an efficient grasping action. (1 mark)

5. Treeshrews have claws instead of nails. Nails are a primate feature, so this is a non-primate feature. (1 mark)

Treeshrew: Image Source

Revision Questions

1. An omnivorous diet includes both plant and animal material.

2. A nocturnal animal is more active at night than during the day.

3. Prehensile means grasping, for example, a prehensile hand or prehensile tail.

4. Brachiation is the method of locomotion where an animal swings by its arms.

5. A herbivorous diet consisting of only plant material.

6. Tree-dwelling animals are arboreal.

7. Quadrupedal describes an animal walking on all four limbs.

8. Vocalisation is communication using sounds produced by the throat.

9. Ground-dwelling animals are terrestrial.

10. Knuckle-walking is quadrupedal locomotion using the soles of the feet,
but with the hands turned under.

Revision Questions

1. The human vertebral column is S-shaped.
It is most narrow at the top and broadest at the bottom.

2. The human pelvis is shorter and broader than the ape’s pelvis
because it carries a greater proportion of the body weight.

3. The transverse foot arches are unique to humans.
They assist with the striding motion as each foot pushes off the ground.

4. The precision grip is unique to the human hand.
It allows fine manipulations such as writing and threading a needle.

5. The human brain is approximately two to three times bigger than the ape’s brain.
The human brain has an average size of 1,350 cm³ compared to
the ape’s brain which has an average size between 400 cm³ and 500 cm³.

6. Development of the cerebral cortex of the brain
enables greater intelligence in humans.

Test

1. Which is the correct sequence of classification from most general to most specific?

(a) family, class, genus, order.
(b) class, order, family, genus.
(c) order, class, genus, family.
(d) genus, family, order, class.

2. "A group of individuals which are alike and able to interbreed to produce fertile offspring."
This is the definition of a

(a) primate.
(b) family.
(c) hominid.
(d) species.

3. A diet consisting of both plant and animal matter is called

(a) omnivorous.
(b) herbivorous.
(c) frugivorous.
(d) carnivorous.

4. The relative importance of the sense of smell in primates

(a) is increased.
(b) remains constant.
(c) is reduced.
(d) varies with different species.

5. The most accurate name for the form of primate locomotion which involves all four limbs bearing the body's weight, with the forelimbs being about 20% longer than the hind limbs is

(a) quadrupedalism.
(b) brachiation.
(c) bipedalism.
(d) knuckle-walking.

6. Examine the following diagrams of primate feet.

Insert two images.
Remove the identifying names.

A: Chimpanzee Foot B: Human Foot

Which of these statements about feet A and B is true?

(a) A would be capable of prehensility but not capable of opposability.
(b) B would have a longitudinal arch suited to bipedalism whereas A would have a transverse arch suited to quadrupedalism.
(c) B is best adapted to bipedalism because opposability and prehensility are restricted.
(d) A shows adaptations suited to brachiation whereas B would be suited to quadrupedalism.

7. A primate which has a prehensile tail, brachiates as its main method of locomotion, has an arboreal habitat and lives in South America would belong to which group?

(a) Prosimians.
(b) New World Monkeys.
(c) Old World Monkeys.
(d) Lesser Apes.

8. Of the following primates, those most adapted to an arboreal way of life are the

(a) chimpanzees.
(b) gibbons.
(c) gorillas.
(d) baboons.

9. Which of the following primates is LEAST likely to use brachiation as its main method of locomotion?

(a) An ape which feeds on fruit in trees.
(b) An arboreal ape.
(c) A terrestrial monkey.
(d) A monkey which vocalises loudly to communicate over long distances.

10. Which of the following primates would you expect to have the most highly developed cerebral cortex area of the brain?

(a) siamang (a lesser ape)
(b) squirrel monkey (a New World monkey)
(c) tarsier (a prosimian)
(d) macaque (an Old World monkey)

Revision Questions

1. The first digit is opposable if it can be moved so that it can touch the ends of each of the other digits.

2. Prehensile is capable of grasping.

3. A species is a group of individuals capable of interbreeding under natural conditions to produce fertile offspring.

4. Brachiation is locomotion by a form of branch swinging.

5. The cerebral cortex is the outer region of the brain which is concerned with the more intelligent thought processes such as reasoning and problem solving.

6. Quadrupedalism is locomotion on four feet.

7. Walking on two legs is bipedalism.

8. Arboreal means tree-living.

9. A precision grip is where the object is gripped between the thumb and finger, e.g. holding a pencil.

10. A power grip is where the object is grasped between the undersides of the fingers and the palm of the hand, e.g. holding a hammer.

11. A transverse arch runs from one side of the foot to the other.

12. Knuckle walking is a method of locomotion, e.g. gorilla walks on the soles of its feet but turns the hands under so that the knuckles are in contact with the ground, rather than the palms.

13. Pongids are the great apes. They have a larger body size and larger brain size than the lesser apes.

14. Prosimians are the lower primates which do not show all of the primate characteristics. They are smaller in size, with less flexible hands, larger snouts and smaller brains than other primates.

Revision Questions