Upgrade to remove ads
Ch. 19 Human Evolution
Terms in this set (29)
-the coalescent event between the alleles at this locus predates the speciation event (also called incomplete lineage sorting)
-more often seen in large populations bc more polymorphisms are preserved
principal features for divergence of humans from chimps
-dentition and skeletal changes for bipedal locomotion
skeletal changes for bipedal locomotion
-Foramen magnum directly below the skull in hominins
-The pelvis is shortened and broadened
-Femur is elongated and angled inward
-Foot is arched for walking and big toe is aligned with other toes
-mode 1 tools: are simple and include chipped flakes obtained by striking a core stone at an angle with a "hammer" stone
-date back 2.6 MYA
Megadont Archaic Hominins
-Huge muscle attachment regions on the skull (protruding cheek bones)
-Anchor massive chewing muscles
-Had correspondingly large teeth (megadont)
-Probably grinded low quality food sources
-mode 2 tools: Known as bifaces, sharp edges running along both sides
-Appeared in Africa 1.6 MYA
-Decrease in size of jaw, molars, and digestive tract,
-Increase in female body mass
-Massive growth in size of brain
Suggests all of these changes a result of the use of fire
-MRCA of homo Sapiens, Denisovans, and Neanderthals
-Derived from H. ergaster but with high and rounder cranium, with a larger brain
-Difference: Powerful brow ridge but similar facial structure to humans
-used Acheulean tools (mode 2), but later used Levallois technique (mode 3 technology)
*-Most researchers believe H. sapiens evolved from H. heidelbergensis 200,000-130,000 years ago
Homo florensiensis (actual hobbits)
-1m tall humans found in Indonesia that went extinct ~12,000 years ago (discovered 2004)
-flat faces and overall skull geometry place them in Homo (had tiny brains and share many physiological features with archaic hominins)
-Stone tools and charred, cut animal bones, found near remains
-Taxonomic placement uncertain
-found in 2015 in a cave in South Africa (Dated between 335,000 and 236,000 years ago)
-Homo characteristics: highly dexterous hands, human-like feet for walking, reduced jaw and teeth, cranial structure
-Still, limb morphology and brain size more similar to archaic hominins
Emergence of Anatomically Modern Humans
-H. ergaster, H. erectus, and H. heidelbergensis underwent remarkable expansion
-Likely due to innovations in physiology, fire, and toolmaking
-Spread of tool-making
-hominins left Africa and colonized the rest of the Old World in 1 wave (all at once)
-h. ergaster left Africa, evolved into h. heidelbergensis, which then evolved into Homo Sapiens
Out-of-Africa Hypothesis (model on slide 58)
-hominins left Africa and colonized the rest of the Old World in 3 waves
-1st wave: H. ergaster migrated into Europe and Asia evolving into H. erectus 2 MYA
Subsequently, H. heidelbergensis arose from H. ergaster in Africa
-2nd wave: H. heidelbergensis migrated into Europe and Asia where it evolved into H. neanderthalensis and the Denisovans ~ 400,000 years ago
-3rd wave: H. sapiens evolved from H. heidelbergensis in Africa between 200,000 and 130,000 years ago
Evidence for Out-of-Africa Model
1. Successive toolmaking technologies arose in Africa and spread in consecutive waves
2. Fossil evidence suggests gradual divergence of the premodern Homo species in their various locations of Africa, Europe, and Asia
3. Greater mitochondrial genetic diversity in Africa (also nuclear data)
- Using molecular clock estimated that we share a common ancestor 120,000-230,000 years ago
- Non-African mtDNA coalesces 38,000 years ago
Data on mitochondrial genomes tells us 2 things:
1. The MRCA of humans dates beck to the emergence of H. sapiens, not H. erectus
2. Non-African H. sapiens share an even more recent common ancestor, dating to about the time humans replaced other hominin species
-derived from heidelbergensis
-Compared to modern humans: heavier, stronger, more stocky, more pronounced brow ridge and larger eyes
-Made elaborate mode 3 tools and hunted large game, cooked with fire, and probably capable of some degree of speech
-Buried their dead and cared for sick, injured, or elderly
-derived from heidelbergensis
-Only known from a single finger bone and a couple of teeth found in a cave in the Altai mountains
-Understand a decent amount because genome was sequenced
-Migrated out of Africa ~60,000 to Europe and Asia where other Homo species were present (Thousands of years of coexistence)
-Compared to H. heidelbergensis: rounded cranium with larger brain, a pronounced chin, smaller teeth, reduced brow ridges, more slender bodies with longer limbs and a shorter torso
Upper Paleolithic Lifestyle (40-50 kya)
New Behavioral and Cultural Traits Developed:
-Production of increasingly advanced mode 4 tools using bone and ivory
-Elaborate structures for shelter
-Produced art and musical instruments
-Buried dead in ceremonial manner
-Traded material across long distances
-Language was also possibly fully developed at this stage
Why has it been so difficult to resolve the phylogenetic history of the hominin clade?
All species in the clade are extinct except for one, and there is very limited information about the other species
What are the hominin radiations depicted in this figure, which illustrates the out-of-Africa hypothesis?
Homo ergaster leaves Africa and becomes Homo erectus in Asia; Homo heidelbergensis evolves in Africa from Homo ergaster and spreads into Europe where the Neanderthal/Denisovan lineage branches off; Homo sapiens evolves from Homo heidelbergensis in Africa and spreads worldwide, replacing resident hominins.
Which of the following is NOT a line of evidence that supports the out-of-Africa model?
Discoveries of complete fossils of several Homo species that provide morphological evidence supporting radiation from Africa
How is hominin radiation depicted by the multiregional hypothesis?
Hominins leave Africa and colonize the rest of the Old World a single time as Homo ergaster. Homo ergaster populations in different parts of the world diverge morphologically but do not speciate. Eventually, they evolve into Homo heidelbergensis and then modern humans.
Many of the first hominins had small cranial capacity and some capacity for upright locomotion. The foot morphology of Ardipithecus ramidus, an early hominin, had a gripping opposable toe. What does this suggest about its locomotion?
It indicates that A. ramidus was at least partially arboreal, or living in or among the trees.
Which of the following was NOT a characteristic of Homo naledi that was also shared with the rest of the Homo genus?
NOT larger brain
feet adaptated for upright walking
reduced jaw and teeth
Which morphological change would NOT be associated with a reduced nutritional challenge for modern humans?
NOT decrease in female body mass
decrease in size of the jaw and molars
decrease in size of the digestive tract
significant increase in brain size
Which of the following is TRUE regarding the possible interbreeding between the human and Neanderthal species?
A limited amount of variation has been passed from Homo neanderthalensis to Eurasian populations of Homo sapiens as a result of interbreeding that probably took place in the Near East at some point within the past 100,000 years.
What became the most important adaptation for hominins that moved out of the African forest onto the savannah?
How did Homo neanderthalensis differ from Homo sapiens morphologically?
Neanderthals were heavier, stronger, and more stocky, with more pronounced brow ridges and larger eyes.
THIS SET IS OFTEN IN FOLDERS WITH...
Ch.1 Overview of Evolutionary Biology
Ch.2 Early Evolutionary Ideas and Darwin's Insight
Ch. 3 Natural Selection
Evolution Exam 2
YOU MIGHT ALSO LIKE...
Evolution Chapter 19
Anthropology Ch. 6-7
Bio Anthropology Exam 4: McKeown TXST
Rise of Homo
OTHER SETS BY THIS CREATOR
Pharmacology: Ch. 5
Pharmacology: Ch. 1, 2, & 4
Pharmacology Final Review