The Emergence of Primates and Early Hominin Evolution

Question 1

What does the term primates include?

Answer 1

humans, apes, monkeys, and prosimians

Question 2

State 5 characteristics of primates.

Answer 2

opposable thumbs, quadrupeds, decently large brains, smaller snout, reduced sense of smell, social, flattened nails grasping hands and feet, expanded visual areas, forward facing eyes, reduced ears, rotating forearm, ridged fingertips with nerve endings

Question 3

What is the definition of a prosimian?

Give an example.

Answer 3

Pre-monkey; for examples lemurs

Question 4

Define the term arboreal.

Answer 4

Adapted to life in the trees

Question 5

True or false? Humans and chimps are the only bi-pedal primates.

Answer 5

False; only humans are

Question 6

Describe generalized dentition.

Answer 6

Different teeth allows for varied diet

Question 7

What is phylogeny?

Answer 7

the evolutionary history of a species

Question 8

Genetics diverged with chimps about ___ million years ago.

True or false? Humans are more closely related to chimps than gorillas.

Answer 8

6; true

Question 9

How old is the first fossil with primate characteristics?

Answer 9

65 mya

Question 10

What is considered by some as the earliest primate?

Answer 10

Purgatorius: a proto-primate that resembles a weasel or a rodent-like creature

Question 11

What time range are the first fossils with monkey characteristics from?

Answer 11

30 to 40 mya

Question 12

What time period did primates with ape characteristics emerge and what trait signified this?

Answer 12

20 mya; lack of tail

Question 13

What time period is known as “The Golden Age of Hominoids” and why did it get this term?

Answer 13

Miocene Epoch 23-5 mya; thousands of fossils in Africa, Asia, and Europe

Question 14

What is the meaning of homonoid and hominin?

Answer 14

Homonoid: “ape-like”
Hominin: “human-like”; humans and any creature in direct human line

Question 15

At what point in the Miocene did bipedal hominins appear?

Answer 15

the end

Question 16

When did bipedalism emerge?

Answer 16

7mya

Question 17

What skeletal characteristics indicate bipedalism?

Hint: Human

Answer 17

(1) S-shaped spine for balance with curves at cervical and lumbar
(2) foremen magnum positioning is at the base of the skull
(3) pelvis; ilium is short and broad
(4) femur is curved inward so feet are at the centre of gravity
(5) shortened big toe and straight toes; foot is arched to absorb shock and energy; more tightly bound foot bones
(6) Tibia articular surface (where it connects to femur) is larger in bipeds

Question 18

What are the skeletal characteristics of apes?

Answer 18

(1) c-shaped vertebral column creating the tendency to fall forward
(2) ape pelvis ilium is long and narrow
(3) foremen magnum is positioned out the back of the skull
(4) straight angle of the femur
(5) thumb-like, grasping big toe for climbing; flat footed

Question 19

What are the 4 theories for the explanation of bipedalism.

Answer 19

(1) the upright provider: bipedalism allowed males to carry more food back to camp
(2) the upright scavenger: higher vantage point, free hands to gather, more energy efficient
(3) The efficient walker: requires a 1/4 of the energy of an ape, travel great distances for food (like grazers)
(4) The endurance runner: adapted for more efficient and faster running (hunting)

Question 20

True or false? Half of early hominin sites are in Africa.

Answer 20

False; All of early hominin sites are in Africa

Note: mostly in the East, some in the south, recent discovery in Chad

Question 21

True or false? Upright walking emerged way before human characteristics of the brain.

Answer 21

True

Question 22

Explain the theory that bipeds originated in the woodlands instead of the savannah.

Answer 22

Skeletal features in the hands and feet show continued life in the trees

Question 23

What are the Australopithecines?

Answer 23

Diverse genus of hominins that existed in the time period 4.2-1.9 mya. Possessed small brains and prognathic faces, and large teeth and jaws. Bipeds but maintained the ability to climb. All located on the African continent.

Question 24

Describe diastema.

Answer 24

Space in the jaw that allows space for large teeth

Question 25

What is sexual dimorphism?

Answer 25

Difference in size/physical characteristics between males and females

Question 26

There have been no artifacts of stone tools correlated to the Australopithecine, what evidence suggest they may have used tools?

Answer 26

Hand bone analysis; metacarpal bones (specifically trabecular bone under the joint remodels)

Question 27

What are three characteristics of robust australopithecines?

Answer 27

(1) Megadontia (really large teeth–molars + premolars– and jaws
(2) broad zygomatic (wide cheekbones make room for chewing muscles)
(3) Large sagittalcrest (ridge alongtop of skull to anchor chewing muscles)

Question 28

Robust Australopithecines eat a ____ diet, but are able to eat softer _____ material.

Answer 28

course, fibrous; plant

Question 29

What is Olduvai Gorge, Tanzania and why is it important?

Answer 29

Important hominin site in the Serengeti plain of Northern Tanzania (in the Great Rift), where sediment layers are pronounced producing reliable dating; exposing 2 million years of Earth’s history.
Volcanic processes provide better preservation through rapid sedimentation & Gorge makes the artifacts more easily accessible.
Discovered by the Leakeys.

Question 30

What are four trends in hominin evolution?

Answer 30

(1) Bipedalism
(2) Expansion of the brain (eating more protein for brain growth)
(3) Reduction of the face, teeth, and jaws
(4) tool making and utilization

Question 31

Compared to Australopithecines, what traits do Homo habilis exhibit?
Hint: theres four

Answer 31

Larger brain, smaller teeth and jaws, less prognathic faces, and the presence of material culture

Question 32

Homo ______ is the earliest proven user of stone tools.

Answer 32

habilis

Question 33

Homo ______ is the earliest proven user of stone tools, however evidence of stone tools date ____ mya.

Answer 33

habilis; 3.3

Question 34

What are the different kinds of Oldowan tools and how were they made?

Answer 34

Manufactured by percussion flaking; include hammer stones, choppers, and flakes

Question 35

What species was the first to leave the continent of Africa?

Answer 35

Homo erectus