Hominoid Fossil Record/Ardipithecus

Question 1

Richard Leaky

Answer 1

discovered nearly complete skeleton of a Homo erectus youth, discovered “Turkana Boy”

Question 2

Louis Leaky

Answer 2

Argued finger bones and fragments constituted a unique hominid line; Homo Habilis.

Question 3

Sarich and Wilson

Answer 3

Fundamental research with DNA evidence/comparison to show that man is genetically more similar to African apes than OWMs, paper titled “A Molecular Time Scale for Human Evolution”

Question 4

Adolf Schultz

Answer 4

Developed theory of primate development to show how non-human primates have a different growth period, lifespan, and period of fertility than humans

Question 5

Robert Broom

Answer 5

Did medical studies of vertebrate paleontology, recovered many important specimen from 1930-1940. Discovered the first adult Australopithecus africanus.

Question 6

Raymond Dart

Answer 6

An important biologist who found the first Ardipithecus fossil. 1924-1950

Question 7

Don Johanson

Answer 7

Discovered Lucy in 1974

Question 8

Tim White

Answer 8

Worked on Lucy, but mostly known for his discovery of Ardipithecus ramidus.

Question 9

Middle Awash

Answer 9

Ethiopian paleoanthropological research lab for studying hominins particularly Australopithecines and Olduwan artifacts; area provides most evidence for human evolution as many remains found here as well

Question 10

Sterkfontein

Answer 10

Considered the “cradle of humankind” located in South Africa with the discovery of hominin remains to australopithecus and Early homo.

Question 11

Swartkrans

Answer 11

An early Pleistocene site located in South Africa which contained over 300 specimens, representing nearly 130 Australopithecus robustus individuals

Question 12

Taung

Answer 12

the Taung Child is fossilized young Australopithecus africanus discovered in 1924 in Taung, South Africa

Question 13

“First Family” (333)

Answer 13

Discovered in 1975 by Donald Johanson in Ethiopia consists of 13 Australopithecus afarensis individuals of different ages, considered to be the “first family”

Question 14

Albumin

Answer 14

Molecule studied that has evolved at a steady rate and applies that apes and humans have a more recent common ancestor than humans and OWMs

Question 15

p & q arms

Answer 15

two arms of chromosome, shorter arm is p and longer arm is q

Question 16

karyology

Answer 16

The study of cell nuclei, especially in reference to the number and shape of the chromosomes. G-banding is a technique that strains the chromosomes so their karyotype becomes visible. This can be used to identify recurrent bands to make a chromosome map.

Question 17

metacentric

Answer 17

A chromosome whose centromere is centrally located, making the chromosomal arms (p & q arms) almost equal in length. A metacentric chromosome has an “X” shape.

Question 18

acrocentric

Answer 18

A chromosome where the centromere is not central, and is located near the end. The p arms will be shorter while the q arms are longer. A Acrocentric chromosome has a “x” shape but the arms are unproportioned.

Question 19

Sahelantropus

Answer 19

An extinct species of hominid dating to approximately 7 mya, first primate to use habitual bipedal locomotion.

Question 20

sectorial canine complex (CP3 honing complex)

Answer 20

“Social” tooth, used for male-to-male reproductive competition

Question 21

canine “honing”

Answer 21

Arrangement of the upper canine and lower third premolar that allows the edge of upper canine to be sharpened or honed against the front edge of the lower premolar.

Question 22

AIIS

Answer 22

anterior inferior iliac spine serves as the attachment point for the straight head of the rectus femoris muscle. This keeps the pelvis from tilting and staying upright.

Question 23

stance phase

Answer 23

The part of the bipedal gait cycle which the foot remains in contact with the ground.

Question 24

swing phase

Answer 24

The part of the bipedal gait which thrusts the limb forward until it hits the ground, it is the phase between toe off and heel strike. Illius soras is the muscle used in this swing, in conjunction with other muscles, pushes the knee forward, creating a lot of velocity.

Question 25

gluteus maximus

Answer 25

Keeps the trunk stable during the swing phase of bipedal locomotion, keeps you from falling over.

Question 26

gluteus medius

Answer 26

Stabilizes the pelvis so your pelvis does not drop toward the ground.

Question 27

gastrocnemius

Answer 27

this is the key muscle of the calf, flexing the knee and foot. It runs to the Achilles tendon and forms two heads attached to the femur. Gastrocnemius is an important planta flexor in the “toe off” phase so the knee and foot can bend.

Question 28

soleus

Answer 28

Functions as a knee extensor and an ankle planar flexor.

Question 29

plantarflexion

Answer 29

A movement in which the top of the foot points away from the leg; standing on the tip of your toes, or pointing out toes. The main muscles that a plantar flexors are the gastrocnemius, soleus, and plantaris.

Question 30

plantar aponeurosis

Answer 30

The modification of deep fascia that covers the sole of the foot, thick connective tissue that supports vital structures of the foot. The presence of this structure suggests the the foot is adapted for both terrestrial and arboreal locomotion in African apes

Question 31

metatarsophalangeal dorsiflexion

Answer 31

An extension of the metatarsophalangeal joints that is performed by extensor tendons that pass to the digits. The toes are elevated towards the dorsal surface of the foot. The extensor muscles that are used are; extensor hallucis longus, extensor digitorum longus, and extensor digitorum brevis.

Question 32

Approximately what percent of the human genome shares domain sequences of proteins with
the fruit fly?

Answer 32

61%

Question 33

What is the special significance of chromosome #2 in the human karyotype?

Answer 33

It is the 2nd largest human chromosome, making up almost 8% of the total DNA in cells. It is unique in humans, emerging as a result of the head-to-head fusion of 2 ancestral chromosomes that is separate in other primates.

Question 34

How are chromosomes generally arranged in a karyotype?

Answer 34

Chromosomes are arrange in pairs of 1-22 from largest to smallest. There are 2 chromosome that specify sex, XX for female, XY male.

Question 35

What is knuckle-walking? Why do apes use it?

Answer 35

Knuckle-walking is a form of quadrupedal walking when the forelimbs hold the fingers to that allow for body weight to press down to the ground through the knuckles. This is used by gorillas and chimps b/c they are unable to walk up-right due to a short lumbar column that is unable to become upright.

Question 36

What theory of phalangeal curvature did “Suzi” disprove?

Answer 36

Suzi disapproves Wolfe’s Law, curved structure does not always mean climbing, could be genetically modified

Question 37

What is special about the calcaneal tuber of humans and their ancestors?

Answer 37

In humans and their ancestors, the calcaneal tuber has a large amount of trabecular bone elasticity which allows for forgiveness in the heel as it is used constantly when walking bipedally.

Question 38

Did A. afarensis have a longitudinal arch? What would be its significance?

Answer 38

A. afarensis fourth metatarsals reflect the presence of stiff longitudinal arches. This is significant as they lose an opposable digit that grasped branches in favor of a longitudinal arch (LA) that stiffens the foot and aids bipedal gait.

Question 39

Did A. afarensis have an effective abductor mechanism? If so, what is its significance?
What is a valgus knee?

Answer 39

Yes, allows A. afarensis to walk bipedally and upright. Valgus knee is a lower leg deformity that exists when the bone at the knee joint is angled out and away from the mid-line.

Question 40

What is the significance of the short ischium in hominids? When did it first appear?

Answer 40

Allowed hominids to walk bipedal without having to shift their weight forward and/or use their their forelimbs for balance/locomotion. It first appears in Australopithecus sediba.

Question 41

What is the Central Joint Complex and how do those of hominids differ from those of the
chimpanzee and gorilla?

Answer 41

Central Joint Complex is the combo of the distal and proximal rows of the hand including the trapezium, hamate, capitate, trapezoid, triquetral, lunate, and scaphoid. Chimps and gorillas have ulna withdrawal

Question 42

What is the os peroneum complex and what is its significance in the hominid foot? Do the feet
of chimpanzees and gorillas have this complex?

Answer 42

Muscle that connects to 2nd ray when muscle contracts, you grasp. Humans lengthened this to be able to walk bipedally. Chimps and gorillas do not have this complex because they got rid of it to create a canal to provide more movement of the tendon, turned the foot to hand-like.

Question 43

What is the significance of foot length in its function in hominoids?

Answer 43

The longer the foot, the more you can move it up and down to walk. The short the foot, the more you are able to use it as a hand to grasp things.

Question 44

What special feature of the Ar. afarensis capitate provides substantial evidence of its
palmigrade locomotion?

Answer 44

The head of the capitate is “down off” of the body of the bone, resulting in a large gap. This gap allows for more extreme dorsiflexion, which would be good for climbing and grasping.

Question 45

It was long speculated that the LCA of chimpanzees and humans would have long
forelimbs. Is this the case?

Answer 45

No

Question 46

What bones in the Ar. ramidus foot indicate that it was pleisiomorphically long?

Answer 46

Ardi has a cuboid length similar to OWM, and longer than extant great apes, making them pleisiomorphically long. No gap in between big toe and other toes. They also had dorsoplantar Elongate basis of MT’s, elongated tarsus, a lengthening of their Achilles tendon, and a reduction in the thength of the itermed. phalanx.

Question 47

Among Ardipithecus, Australopithecus and Pan, which taxon has the thickest enamel? Which
has the thinnest? What is the significance of this fact

Answer 47

Pan has thin enamel, only eats fruits and leaves.
Ardipithecus has intermediate enamel. Australopithecus has the thickness enamel.
The thickness of enamel indicates food processing and what kind of foods are being eaten by our ancestors.

Question 48

What was the approximate cranial capacity of Australopithecus afarensis? Of Ardipithecus
ramidus?

Answer 48

Australopithecus afarensis: 450 cc
Ardipithecus ramidus: 300-350 cc

Question 49

The cranial base of Ardipithecus was relatively short and its foramen magnum slightly anterior
relative to other hominoids. What is the significance of these facts?

Answer 49

The skull of Ardi. very closely resembles earlier hominids (Sahelanthropus) and possesses similarities with later skulls (Australopithecus). These aspects indicate that Ardi. is part of human ancestry and that their cranial structure conforms evidence for partial bipedality and are more closely related to humans than chimps. The foreman magnum determines morphological brain enlargement.

Question 50

Some aspects of the Ardipithecus pelvis were similar to those of chimpanzees, while others
were not–explain.

Answer 50

The ilium and ischium have changed he most as the pelvis became wider over time while chimps have a thin pelvis. Some aspects stayed the same. These kind of adaptations indicate that Ardi was both walking upright and doing arboreal locomotion like an ape.

Question 51

What is the significance of the robust MT2 in Ardipithecus ramidus?

Answer 51

The robust MT 2 allows notches through cartilage modeling and rotates the foot to allow for grasping and bipedal walking.