Ch. 17 Human Evolution Flashcards
1
Q
You are ___ from your mother and father.
A
Descended
2
Q
You are ___ to your aunt and cousin.
A
Related
3
Q
Modern humans and our direct and indirect ancestors after our lineage split from the ___.
A
Chimpanzee
4
Q
Hominoidea
Hominoids
A
Superfamily
Apes
5
Q
Hominidae
Hominids
A
Family
Great apes
6
Q
Hominins
A
Members of our lineage after the split from Pan
5-6.3mya
7
Q
Australopithecus
A
Dates as old as 4.2 mya
First bipead apes
8
Q
Earlier than 4.2 mya, the border between ___ and ___ becomes unclear.
A
Hominid and hominin
9
Q
Earliest fossil hominid sites are in ___.
A
Africa
10
Q
The major groups of sites are:
A
Ethiopia
Kenya
Tanzania
South Africa
11
Q
Pre-bipedal hope of life
A
- A skull found in the African nation of Chad
- Sahelanthropus tchadensis
- may be common ancestor of both Panini and Homini
12
Q
Where does this leave us, evolutionary speaking?
A
At a very exciting time as we seek to unravel the history of our species
13
Q
Our understanding of our genealogy is
A
Presently in flux, and each new fossil find sheds more light on our ancestry
14
Q
As new species evolved,
A
- they filled ecological niches
- either gave rise to descendants better adapted to the changing environment
- or became extinct
15
Q
Our own evolutionary history has many ____ side branches
A
Dead-end
16
Q
Primates are difficult to characterize as an ___
A
Order
17
Q
They lack the strong ___ found in most other mammalian orders
A
Specializations
18
Q
Trends in primates
A
- changes in the skeleton
- increase in brain size
- shift toward smaller, fewer, and less specialized teeth
- evolution of stereoscopic vision
- grasping hand with opposable thumb
19
Q
Why did bipedalism become the primary adaptation of hominins?
A
- carrying behavior
- reduction of overall heat stress
- most energy efficient way to travel long distances
- allows for better vision in open environments and defensive action against predators by freeing hands to throw objects
20
Q
The primate order is divided into two suborders:
A
- prosimians, lower primates
- anthropoids, higher primates
21
Q
Prosimians
A
Lower primates
- lemurs, lorises, tarsiers, and tree shrews
22
Q
Anthropoids
A
Higher primates
- monkeys, apes, and humans
23
Q
Old world monkeys
A
Superfamily Cercopithecoidea: macaque, baboon, proboscis monkey
24
Q
New world monkey
A
Superfamily Ceboidea: howler, spider, and squirrel monkeys
25
Superfamily Hominoidea
Apes, humans
26
Family Pongidae
Chimpanzees, orangutans, gorillas
27
Family Hylobatidae
Gibbons, slamangs
28
Family Hominidae
Humans
29
Most primates are highly ___
Social
30
Why is it important that most primates are highly social?
- helps with defense of the group
| - helps with raising young
31
Tribe gorillini
Lineage leading towards gorillas
32
The lineage leading towards humans and chimps is called ___ but only the lineage leading away from chimps and towards H.sapiens represents the ___.
Hominini
| Hominins
33
Modern humans are hominins but are genus ___
Homo
34
Australopiths are Hominins but not genus ___
Homo
35
Chimpanzees are genus ___.
Pan
36
Prosimians are generally small ranging from species the size of a ___ up to those as large as a ___
Mouse up to a house cat
37
Notharctus
A primitive Eocene prosimian
38
As the continents moved northward during the Cenozoic..
- the climate changed from warm tropical to cooler mid-latitude conditions
- the prosimian population decreased in both abundance and diversity
39
By the Oligocene, hardly any prosimians were left in the northern continents as..
The once widespread Eocene populations migrated south to the warmer latitudes of Africa, Asia, and Southeast Asia
40
Presently, prosimians are found only in the tropical regions of...
Asia, India, Africa, and Madagascar
41
Prosimians
Pro means ___
Simian means ___
Before, apes
42
Prosimians are the ___ primate lineage, and their fossil record extends back to the ___.
Oldest, Paleocene
43
During the Eocene, prosimians were...
Abundant, diversified, and widespread in North America, Europe, and Asia
44
Anthropoids evolved from the ___ lineage
Prosimian
45
Anthropoids evolved from a prosimian lineage sometime during the late ___ and by the ___ they were well established.
Eocene, Oligocene
46
Anthropoids are divided into ___ superfamilies.
Three
47
Old world monkey
Suborder:
Superfamily:
Suborder: Anthropoidea
Superfamily: Cercopithecoidea
48
Old world monkeys are characterized by..
- close-set, downward-directed nostrils
- grasping hands
- nonprehensile tail
49
Old world monkeys include
The macaque, baboon, and proboscis monkey
50
Aside from us, ___ are the most widespread and populous primate on earth
Macaques
51
Present-day old world monkeys are distributed in..
The tropical regions of Africa and Asia
52
Present-day old world monkeys are thought to have evolved from..
A primitive anthropoid ancestor, such as Aegyptopithecus, sometime during the Oligocene
53
Much of our knowledge about the early evolutionary history of anthropoids comes from..
Fossils found in the Fayum district, a small desert area southwest of Cairo, Egypt
54
During the late Eocene and Oligocene, this region of Africa was..
- A lush, tropical rainforest
| - supported a diverse and abundant fauna and flora
55
Within this forest lived many different..
Arboreal anthropoids as well as various prosimians
56
One of the earliest anthropoids, Aegyptopithecus, is
- a possible ancestor of the old world monkeys
- a small, fruit-eating, anorak primate, about 5kg
- monkey characteristics and ape features
57
What is the closest link we currently have to old world primates
Aegyptopithecus
58
New world monkey
Suborder:
Superfamily:
Suborder: Anthropoidea
Superfamily: Ceboidea
59
New world monkeys are found only in..
Central and South America
60
New world monkeys probably evolved from..
African monkeys
61
New world monkeys are characterized by..
- prehensile tail
- flattish face
- widely separated nostrils
- include the howler, spider, and squirrel monkeys
62
Great apes
Suborder:
Superfamily:
Suborder: Anthropoidea
Superfamily: Hominoidea
63
The great apes
Family: Pongidae
| - chimps, orangutans, and gorillas
64
The lesser apes
Family: Hylobatidae
| - gibbons and siamangs
65
The Hominoid lineage diverged from..
Old world monkeys
66
The Hominoid lineage diverged from old world monkeys sometime before the ___, but exactly when is still being debated
Miocene
67
As the climate changed, the primate ___ also changed
Populations
68
Prosimians and monkeys became ___, whereas Hominoids diversified in the newly forming environments and became ___.
Rare, abundant
69
Ape populations became reproductively isolated from each other within the various forests leading to..
- adaptive radiation
| - increased diversity among the Hominoids
70
During the Miocene, Africa collided with Eurasia producing..
- Additional changes in the climate
| - provided opportunities for migration of animals between the two landmasses
71
All Hominins are ___
Bipedal
72
Ischium bone in gorillas vs. humans
Gorillas: long and the entire pelvis is tilted toward the horizontal
Humans: much shorter and the pelvis is vertical
73
Upright posture evolved before ___
Large brains
74
Other features that distinguish Hominins from some Hominoids include..
- a reduced face
- reduced canine teeth
- omnivorous feeding
- increased manual dexterity
- use of sophisticated tools
75
At present, no clear consensus exists on the evolutionary history of the hominin lineage partly because..
- of the incomplete fossil record of Hominins, as well as new discoveries
- because some species are known only from partial specimens or fragments of bone
76
Because there is no clear consensus, scientists even disagree on..
The total number of hominin species
77
Skull discovered in Chad that is near 7 mya makes it the..
Oldest known hominid yet unearthed and very close to the time when humans diverged from our closest-living relative, the chimp
78
Currently, most paleoanthropologists accept that the human-chimp population separated from gorillas about ____.
8 mya
79
Humans separated from chimps about ___
5 mya
80
The human/chimp split likely occurred from a large what?
Common ancestral population
81
The oldest, Sahelanthropus tchadensis shows a mosaic of primitive and advanced features
- small brain case and most of the teeth are chimp like
- nose, which is fairly flat, and the prominent brow ridges are features only seen, until now, uh the human genus homo
- may have been bipedal
82
Ardi
- 5.8-5.2 mya
| - not bipedal so not a clear ancestor
83
Five species of Australopithecus
- A. Anamensis
- A. Afarensis
- A. Africanus
- A. Robustus
- A. Boisei
84
Many paleontologists accept the evolutionary scheme in which..
A. Anamensis, the oldest, is ancestral to A. Afarensis, who in turn is ancestral to A. Africanus, as well as the side branch represented by A. Robustus and A. Boisei
85
What is the oldest known Australopithecine?
A. Anamensis
86
A. Anamensis
- discovered at Kanapoi
- 4.2 mya bipedal species
- about 4.9 ft tall and 110 lbs
87
A. Afarensis
- 3.9-3 mya
- fully bipedal
- exhibited great variability in size and weight
88
Lucy
A. Afarensis
89
Hominin footprints were preserved in ___ in Tanzania.
Volcanic ash
90
A. Africanus
- 3-2.3mya
| - flatter face and somewhat larger brain
91
A. Afarensis had a brain size of
380-450 cubic centimeters
92
Chimp brain size
300-400 cc
93
Present-day human brain size
1350 cc average
94
The skull of A. Afarensis retained many ape like features
- massive brow ridges
| - forward-jutting jaw
95
Heavily enameled molars
An adaptation to chewing fruits, seeds, and roots
96
It appears the limbs of ___ may have not been as well adapted for bipedalism as those of ___.
A. Africanus, A. Afarensis
97
Skull of A. Africanus
Known as the Taung Child
- discovered in South Africa
- marks beginning of modern paleoanthropology
98
Robust species
A. Boisei
| A. Robustus
99
A. Boisei lived..
2.6-1 mya
100
A. Robustus lived..
2-1.2 mya
101
A. Boisei
- Powerful upper body
- distinctive bony crest on the top of its skull
- flat face
- largest molars of any Hominins
102
A. Robustus
- smaller than A. Boisei
- flat face
- crown on top of its skull had an elevated bony crest that provided additional area for the attachment of strong jaw muscles
- broad flat molars indicated it was a vegatarian
103
Larger brains are associated with what?
Higher intelligence
104
Why did we need to be intelligent?
- changing environmental conditions require changes of plans
- complex tool using requires a more complex brain
- non-random mating
- primate social systems can reward intelligent social behavior
105
Non-random mating
- keeping track of who your mate is sleeping with ensures clearer paternity
- cheating requires more intelligence too
- both can lead to successful mating with desirable mates and dependable energy investment in mate pairing
106
A selection for larger brains would run up against what problem?
A baby's larger head needing to pass through the bones surrounding the birth canal
107
The solution for the problem of a baby's larger head needing to pass through the bones surrounding the birth canal in place today is..
- Human babies are born very prematurely compared to the offspring of our closest relatives
- the still soft head of a new-born infant is deformed into a tube as it is squeezed through the birth canal
108
The price humans pay for the pre-mature babies is
Increased maternal care
109
Humans did not evolve from ___.
Apes
110
Humans and their ancestors benefited especially because longer periods of immaturity were needed to allow what?
Brain growth and learning
111
Homo habilis
- The earliest known member of our own genus Homo
- lived 2.5-1.6 mya
- remains first found in Tanzania
- coexisted with A. Africanus for about 200k years
112
Homo habilis brain size
700 cc
113
H. Habilis had a larger brain than its ancestors but smaller ___.
Teeth
114
Homo erectus
- widely distributed
- migrated from Africa during Pleistocene
- found not only in Africa, but also in Europe, China, and Indonesia
- evolved in Africa 1.8 mya, moved into southeastern and Eastern Asia 1mya
- survived until about 100k years ago
115
Who were the first hunters of our lineage?
Homo erectus
116
Being the first hunters permitted a large expansion..
In and out of Africa
117
Homo erectus brain size
800-1300 cc
118
Homo erectus characteristics
- skull was thick-walled
- face was massive
- prominent brow ridges
- teeth slightly larger than those of present-day humans
- comparable size of modern humans
119
The archaeological record shows that H. Erectus was a ___.
Tool maker
120
Homo sapiens evolved from who?
Homo erectus
121
Perhaps the most famous of all fossil humans are the ___.
Neanderthals
122
Neanderthals inhabited Europe and the near east from about...
200k to 30k years ago
123
Some paleoanthropologists regard the Neanderthals..
- as a variety or subspecies of our own species
| - others regard them as a separate species
124
Neanderthals name comes from the first specimens found in..
The neander valley near Düsseldorf
125
The most notable difference between Neanderthals and present-day humans is in the ___
Skull
126
Neanderthal characteristics
- skulls were long and low with heavy brow ridges, a projecting mouth, and a weak, receding chin
- brain was slightly larger on average than our own
127
The remains of Neanderthals are found chiefly in..
Caves and hutlike rock shelters
128
Europe's Neanderthals were the first humans to move into truly ___ climates
Cold
129
About 30-40000 years ago, humans closely resembling modern Europeans movies into the region inhabited by..
The Neanderthals and completely replaced them
130
The name given to the successors of the Neanderthals in France
Cro-Magnons
131
Cro-Magnons lived..
35-10 kya
132
During the period of the Cro-Magnons, the development of..
Art and technology far exceeded anything the world had seen before
133
Highly skilled nomadic hunters, Cro-Magnons followed the herds in their ___.
Seasonal migrations
134
Cro-Magnons used a variety of specialized tools in their hunts, including the..
Bow and arrow
135
Using paints made from ___ and ___, Cro-Magnon people painted hundreds of scenes in the ceilings and walls of caves in France and Spain.
Manganese and iron oxides
136
Out of Africa 2 total replacement
Early modern humans have a common female ancestor in Africa 200k years ago, whose offspring then expanded from Africa to Eurasia and replaced all the other Hominins which existed everywhere on earth
137
AMH could have out-competed because their ___ and ___ was superior.
Hunting and technology
138
Multiregional view
- early humans didn't have an isolated origin in Africa
| - evolved independently in separate regions throughout Eurasia
139
Strict multiregionalism is ruled out by..
Mitochondrial and y-chromosome common ancestry which is African and recent
140
The "continuity" model
Proposes that some level of gene flow occurred between AHM and Neanderthals
141
Occasional contact and interbreeding between these populations enabled our species to..
Maintain its overall cohesiveness, while still preserving the regional differences in people we see today
142
Rebecca Cann argued that..
The geographic region in which modern people have lived the longest should have the greatest amount of genetic diversity
143
___ has the greatest human genetic diversity of any region on earth.
Africa
144
Cann concluded that from the present diversity of mitochondrial DNA, that all humans shared a common female ancestor about ____ years ago in ___.
200,000 years ago in Africa
145
Like homo erectus, East Asians today commonly have what while Africans and Europeans rarely do
Shovel-shaped incisors
146
Outside of Africa, ___ does have the greatest genetic diversity
Asia
147
New assimilation model
- middle ground and incorporated both of the old models
- first modern humans did evolve in Africa, but when they migrated into other regions they did not simply replace existing human populations
- they interbred to a limited degree with late archaic humans resulting in hybrid populations
148
In Europe, the first modern humans appear in the archaeological record rather suddenly around ___ years ago
45-40k
149
Denisovans
New line of the human family tree
| - little finger bone from Denisova cave
