AN101 exam 3 pt 2

what was discovered in 1856 in the Neander Valley in Germany?

Homo neanderthalensis

• the first 

La Chapelle-aux-Saints, France

“Classic” Neandertal

• first nearly complete skeleton 

  • became the basis for the “classic” image 

    • Marcellin Boule’s incorrect reconstruction of it 

what is the common misconception of neandertals?

seen as stopping, brutish individuals

how did these misconceptions arise? 

1. flawed reconstruction of on the earlier neandertal skeletons discovered 

2. an oversight of the fact that this skeleton had severe, debilitating arthritis 

   1. this may or may not have contributed to the flawed reconstruction

know that their anatomy is similar to humans

what is the distribution of neandertals?

across western part of eurasia & middle east

where do neandertals fit?

• 150kya and 40kya 

  • may go back as early as 600,000-800,000 ya 

• show many similarities to anatomically modern H. Sapiens

  • some key differences 

• taxonomists debate as to whether they should be their own species (h. neanderthalensis) 

• or a subspecies of h. sapiens (h. sapiens neanderthalensis) 

  • based on their anatomical similarities and differences to modern humans 

Homo neanderthalensis: Anatomy

• short, robust and heavily muscled 

• thick long bones and large joints 

• barrel-chested 

• anatomy points to a cold-adapted species 

Homo neanderthalensis: cold adaptations

• large nasal opening and barrel chest may have allowed for better warming of air during respiration 

• short, robust stature conserves heat 

• the limb proportions resemble those of modern ppl living in arctic 

but… neandertals also lived in more temperate areas

• paelobotanical reconstruction of plants found around Bolomor cave (eastern spain) 350k-120kya 

• based on plant DNA found in the cave associated w/ neandertals 

Homo neanderthalensis: cranial morphology

profile: rounded but low with receding forehead

• double arch brow ridges 

• laterally thinner than medial 

• large round orbits 

• mid-facial projection 

• high, prominent nose 

• lambdoidal flattening 

• suprainiac fossa 

• occipital bun 

• large juxtamastoid eminence 

• small mastoid process 

• retrmolar space 

• mental foramen under M1

• no chin 

• high coronoid

distinctive inner ear morphology 

Homo neanderthalensis: anatomy 

very unique features

• high, wide, and large nose

• midfacial projection (prognathism)

Homo neanderthalensis: very large brains

• endocranial capacity 1245-1740cc

  • average is 1520cc

• some have larger brains than modern humans

  • difference in brain shape inside skull 

Homo neanderthalensis: vault shape

maximum cranial breadth at diff positions on vault

• side walls parallel in humans 

  • but for neanderthals the max is in the middle 

Homo neanderthalensis: teeth 

• very large, worn anterior 

• shovel shaped incisors 

• small posterior teeth 

• back premolars (p4) of lower jaw have:

  • extra cusps

  • asymmetric

• molars have taurdont roots:

  • expanded pulp cavity

  • fused roots

  • cna sustain more wear

Homo neanderthalensis: development

• teeth formed over a shorter time than in modern humans

• dental eruption was more advanced

  • implcation: dental development related to life history - so they developed faster than modern humans

some neandertals had red hair

• pigmentation gene (mc1r) extracted from bones of 2 neandertals

• unique gene to them (not seen in 3700 living ppl)

• gene impairs pigment receptors

  • causing red hair and pale skin

    • (in some neandertals others had darker hair and skin)

neandertals at shanidar cave

• several partial skeletons recovered in site in northeastern iraq

  • important bc they give us info about neandertal anatomy & behavior 

H. neanderthalensis

kebara cave, Israel 

60,000 BP 

• 1 male 30-45 years of age, 5’7”, 1600cc brain size 

  • paralyzed right arm

  • several pathologies

• the fact that this individual was able to survive despite his injuries has been interpreted as evidence of compassion & community care of non-productive individuals

neandertals & symbolic behavior

they were the 1st ppl to deliberately bury their dead

• flower pollen found in grave

additional burial evidence at several other sites in Europe

• body is clearly moved into fetal position

• animal bones and stones buried along w/ body

Kebara Cave

• 4 deliberate burials

neandertals: Mousterian tools

• thinner blades, more complex tools, w/ more cutting edge 

• evidence of hafted arrow heads 

• evidence for “glue” to secure onto spears

• strong evidence for foresight, planning, and mental templates 

• non-stone materials such as bone, wood, ivory 

neandertals: chatelpoerronian tools 

western & central european sites neandertals and anatomically modern humans coexisted around 35kya 

• associated w/ chatelperronian tool industry at these sites

• lots of fine blades and even adornments 

• chatelperronian industry is found between 35-29kya, derived from earlier mousterian industry 

neandertal diet

• evidence of hunting big game 

  • chemical analysis of bones 

• may have incorporated large quantities of meat into their diet 

• used spears 

neandertal behavior: cannibalism?

• some fossils from neandertal sites show evidence

  • example: fossils at a site in France show tool marks on neandertal bones, indicative of porcessing marrow and brain 

  • evidence bones were cooked, same processing as animal bones 

  • same cut marks on nenadertal bones as on antelope bones

    • did is actually occur or was this just burial processing? 

    • if yes, was it due to ritual practice, starvation or was it common? 

neandertal behavior: shanidar cave

suggests that they led very rigorous lives, and sustained many injuries

• how were they sustaining injuries? 

  • possibly injuries sustained during big game hunting 

  • inter or intra group aggression 

neandertal behavior: how were they using their teeth?

• anterior teeth are well worn and often chipped

• microscopy studies show teeth may have been used to hold hides

• practice seen in modern arctic peoples 

  • (but teeth more worn than any modern people) 

neandertal behavior: “sheltering behavior”

• archeogical evidence

  • hearths 

  • cooking 

  • wind-breaks 

  • clothign/skins 

where did the neandertals go?

• disappeared by 40kya

• in all likelihood, they were simply out-competed by anatomically modern humans (h. sapiens) and went extinct 

• climate and small population sizes may also have played a role in their disappearance 

• the role that anatomically modern humans played in neandertal demise is debatable 

neandertal: nuclear DNA?

• analyzed a complete sequence of nuclear genome

• if neandertals contributed no genes to living populations, they should be equally related to all living ppl

• sequences whole genomes from ppl in France, China, and Papua New Guinea outside Africa, and Yoroba and San inside Africa

  • genomes of non-africans were more similar than were those of Africans

  • 1-4% of the genome of non-Africans was derived from Interbreeding w/ neandertals

    • suggests that non-Africans interbred w/ Neandertals when they dispersed from Africa

New findings: Africans DO have neandertal DNA

• new methods reveal Africans also carry signal of Neandertal DNA (0.5%)(not just non-Africans 1-2%)

  • compared DNA of 2504 ppl w/ DNA extracted from Neandertal fossils

1. Gene flow between early dispersing H. sapiens and Neandertals (100k-150kya)

2. migrations back to Africa from ancestral H. Sapiens in Europe

• all modern human populations studied have Neandertal ancestry

• genes related to immune function and sensitivity to ultraviolate radiation

• introgression = gene flow between species due to back-crossing of hybrids

introgressions

gene flow between species due to back-crossing of hybrids

New findings: interbreeding in Paleolithic H. sapiens and Neandertals

• earliest known Late pleistocene modern humans in Europe had recent neandertal ancestors

  • 3 individuals 45,930-42,580 ya

• more closely related to present day and ancient populations in East Asia & American than later Eurasian populations

• mixing between H. sapiens and neandertals was common

where did inter-breeding occur?

europeans and Asians equally related to neandertals - suggests interbred in Middleast before modern humans dispered to Europe and Asia

• most likely in middle east where modern humans and neandertals overlapped for 50k years 

• since no mitochondrial DNA has been detected in humans, could imply neandertal males mates w/ h. sapien females 

which neandertal genes do we have? 

• incorporated genes through recombination 

• thus, we have a mosaic of neandertal genes 

• each individual may have a different combination of neandertal genes

neandertal genes may even help protect against COVID

• genes cluster on Chromosome 3 increased risk of respiratory failure after COVID-19 infection

• Inherited from Neandertals and found in 50% of S. Asians and 16% of Europeans

BUT

• allele haplotype of chromosome 12 associated with 22% reduction in risk of becoming severely ill from from COVID-10

• encodes proteins important during infections w/ RNA viruses

The Denisovans

denisova cave, Siberia

• 30-50kya

• Finger bone and molar

• DNA distinctive from modern humans and Neanderthals

• Denisocan genes found in Melanesia - 4-6% of genetic material

Modern humans origins: genetic evidence

2 types of evidence:

• study of living people to determine most recent common ancestor (MRCA)

  • Mitochondrial DNA

  • Y-Chromosomes

  • Nuclear DNA

• Study of Ancient DNA

Modern human origins: mitochondrial DNA

• inherited only from the mother

• Rapid rate of evolution

• NO NEANDERTAL mitochondrial DNA in modern humans

  • BUT, NEW evidence of denisovian mitochondrial DNA is present in living humans

• Oldest branches in Africa

• Suggests MrCA between 90-80kya

• Genetic bottle neck: founding population of ~10k individuals who left Africa

• Y chromosome also supports 100k-180k MCRA

• What does this imply about mating and/or survivorship

  • Sing nomitochondrial DNA has been detected in humans, could imply neandertal males mated w/ female Homo sapiens

So where else did the Neanderthals and denisovans go?

In us, interbreed w/ Homo sapiens

What genders are unique to modern humans?

These all show POSITIVE SELECTION in humans

Genes associated with

• sperm function

• Wound healing

• Epidermis - sweat gland, hair roots and tongue

• Skin pigmentation

Genes associated with cranial and upper ody morphology

• protruding frontal bone

• Clavicle and shoulder morphology

• Rib cage shape

Genes associated with cognitive capacities

• Down’s syndrome

• Schizophrenia

• Autism

The emergence of Homo sapiens

• contemporary data shows that modern humans evolved in Africa sometime around 200-160kya

• Between 100-50kya humans spread throughout the world

the most likely scenario for modern human origins

likely multiple migrations out of Africa with interbreeding between migrants and local neandertal, denisovian and other populations

• there was introversion (mating ‘back’) w ancestral populations

• There was ‘back’ migration to Africa from H. Sapiens in Europe who had interbred w/ Neanderthals

traits of Homo sapiens

• Longer limbs than Neanderthals (and other hominins)

• Skeletons are less robust

• Small brow ridges

• Small incisors

• Pyramidal mastoid process

• Definitely chin

Distinguishing features of Homo sapiens

• vertical forehead

• Small face w/ protruding chin

• Les robust post-cranial skeleton

Homo sapiens sites

• Africa

• Europe

• Middle East

Homo sapiens in Africa

Herto (Ethiopia)

• 160kya

• More robust facial features than later anatomically modern humans (AMHs)

• Cranial capacity 1450cc

• Does not have neandertal traits

  • Ex: mid face pregnant him, wide nasal opening

Homo sapiens in the Near East

Skhul Cave (Israel)

• 115ky

• High cranial vault

• Small anterior teeth

• ~1400cc

Homo sapiens in Europe

Cro-Magnon (France)

• 30kya

• Small anterior teeth

• Female skull has very modern appearance

  • No large brown ridges

• Males have more robust features

The bones of Cro-Magnon were the 1st fossils of modern humans discovered in Europe (1868)

Homo sapiens in Australia

Know Swamp (Australia)

• 13kya

• Cranial traits not as modern

  • Receding forehead, pronounced brow ridges

• Postrcranial traits are very modern

  • Slender long limbed

Homo sapiens: explosion of symbolism

• early H. Sapiens were skilled artisans, creating sculptures and cave paintings

modern humans evolved symbolic culture

Behavioral changes w/ H. Sapiens

tools continue to become more refined over time

• like blades

Tools are made from a wider variety of materials that are not always found locally

clear evidence of trade

Indicates high inter-group tolerance

• reliance on resources that vary extensively in space and time

• High risk resource shortfall

• Evidence of wide scale trade w/ evolution modern Homo Sapians ~200-400kya

Compared to Neanderthals and other earlier hominins

early H. Sapiens

• lived at higher population densities

• Lived longer lives

• We’re less likely to to incur serious juries or suffer from disease

• Developed more complex shelter and clothing

Upper Paleolithic house floor

le cerisier, France, ca. 14kya

• A site in Russia was littered with mammoth bones and teeth, several hearths

Homo sapiens: burials

good evidence of ritual burials by early H. Sapiens

• remains of a hat

• Ivory beads/bracelets

the peopling in of the world

based on the Complete Replacement model, modern humans left Africa ~100kya & quickly colonized the other continents

the peopling in of the world: Australia

• had definitely reached by 40kya

  • Possibly as early as 60kya

  • There may have been more than 1 migration

• Colonizing would have required ppl to cross water

  • 70 km (43.5 miles) of water w/ no land in sight

Lake mungo

• an earlier site, as old as 40kya

• Burials

• Evidence of cremation at 26kya

• Red ochre in graves

the peopling in of the world: the americas

• an ice-free corridor linked Alaska and the southern regions after 13kya and before 30kya

• The most likely route by which ppl moved into north & south __ was over Bering Land Bridge, which was exposed during the glacial period

  • May have walked across the land bridge & floated on ice

  • However, they arrived so quickly at the tip of South __ that they prob used boats!

  • Little evidence of their migration, many early sites may now be underwater

  • There may have been multiple migrations

The Clovis people

named for a site in New Mexico is the earliest easily-identifiable culture in America

• 11,300-10,500 ya

• Lived throughout North America, and hunted big game

the arctic

1st colonized approx. 8kya

• especially difficult place to live: cold, dark, little available food

• Ppl have a well-adapted culture to deal with. These difficulties

  • Clothes

  • Tools

  • Social & economic system

Peopling of the pacific

islands divided into near and Remote Oceania

• near Oceania: around 45kya

• Remote Oceania: around 3.5kya

Polynesia

one of the last places on earth to be colonized by humans (5000 BC- 300 AD) due to geographical difficulties

Change in brain size is a

major feature of human evolution

• chimp = ~380 cc

• Modern human = ~1400 cc

Organization of the human brain

cerebrum: “higher” brain functions, divided into lobes

• frontal

• Parietal

• Temporal

• Occipital

Brain stem: metabolic

Cerebellum: balance, posture, movement

Tehran evolving hominin brain

•A. afarensis 400-500cc
•Homo habilis 500-775cc
•H. ergaster/erectus 800-1250cc
•H. heidelbergensis average ~1200cc
•H. neanderthalensis 1245-1740cc
•H. sapiens 1100-1550cc

but … have to consider body size (in relation to brain size)

A chihuahua is much more encephalitis (bigger brained) than a German shepherd - because of strong selection for smaller body size (while brain size stays similar size)

Male gorillas have relatively smaller brains than females bc of selection on them for an increase in body size

reorganization of hominin brain, 3 ways

• region can become larger or smaller

• A functional region can change position

• A functional region can emerge

By looking at the chimp brain and fossil “endocasts” = we know that hominin brain became reorganized

Reorganization of the hominin brain, olfactory bulbs

• olfactory bulbs became smaller in anthropoids

  • In humans ~0,1cc volume

  • In wolves, 6cc in volume

    • Reflects our decreased reliance on smell as a sensory mechanism

Reorganization of the hominin brain, Primary visual region

• primary visual region shifts to interior

• Actually, relatively smaller in humans than chimps

  • Likely due to expansion of parietal lobes in humans - a moor sensory processing center

Reorganization of the hominin brain, Frontal lobe

• increased frontal lobe

  • Increase of 29% in humans and great apes compared to gibbons

  • Absolute size s bigger but.. relative increase is SAME in humans and apes

• Frontal lobe associated with/ analytical reasoning, cognition, memory, and judgment

Reorganization of the hominin brain, temporal lobe

• temporal lobe shows biggest proportional increase

• Increase in white matter - showing greater connectivity

  • Production of spoken language depends on connections between temporal and frontal lobes

Language requires

• regulated breathing that is independent of motor functions

• A low position of the larynx (Adam’s apple) - this has costs

• a smaller oral cavity

• A short but well-muscled tongue placed deep in the throat

  • Good for producing a range of sounds

Most of the difference in anatomical & neurological changes in language is

up in the brain

• Broca’s area = production of speech

• Wernicke’s area = speech comprehension

• but some in the mouth?

Broca’s aphasia

inability to create grammatically complex sentences

wernicke’s aphasia

speech is preserved, but language comprehension/content is incorrect

language lateralization

humans show brain lateralization!

• leads to handedness - most humans are right hand dominant

Chimps have equivalent language areas too!

• symbolic processing Socrates w/ language reflects new connections in humans NOT new structures

to produce language

Chimps do not have the necessary vocal apparatus for speech

Humans thus have a much bigger pharynx

• the area where a lot of speech sounds are produced

The epiglottis also stick up into the back of the nose in most other mammals

• in humans up to the age of ~2 yrs

anatomy & neurology of language, Basicranial flexion (D-E)

High Basicranial flexion is associated with a longer vocal tract

• conducive to speech

  • Look for this on fossil skulls

when did language evolve?

Safe to say autralopithecines and other early hominins prob did not approximate modern speech

• no reason to think that they had communication or speech very much more advanced than modern apes

language in fossil record

• the thoracic vertebrae of the Turkana Boy (h. erectus) suggests he is NOT capable of regulated breathing

• Little basicranial flexion in h. Erectus

• BUT… endocasts show lateralization

• Homo heidelbergenesis shows nicking on right side of teeth suggesting right handedness

Did Neanderthals have language

to answer this question we need to look at:

• vocal tract anatomy

  • Increased flexion, more like modern humans

• Brain anatomy

• Other evidence

• language related to symbolism

  • Evidence of symbolic behavior suggests they may have had language

In 2007, scientists working on sequencing the Neanderthal genome discovered that Neanderthals have the FOXP2 gene that is identical to the gene found in modern humans.

• FOXP2 is, so far, the only gene known to play a role in speech and language

• People with an abnormal copy of this gene have speech and language problems

• likely they had language

genes are also important for language

FOXP2:a gene that is important in language and speech production

• FOXP2 → protein → gene expression related to language”circuits” during development

• FOXP2 mutant → nothing → sever problems w speech & language production

FOXP2 is conserved: this means the basic sequence of nucleotides (and the amino acids they code for) is similar across many species

• FOXP2 is very similar in chimps and humans

  • Shows that new mutations + selection can create novel gene function

Why do humans have SPOKEN language

chimpanzees and other great apes have shown some capacity for understanding language, but many ppl still believe language is uniquely human characteristics

How did language evolve?

It’s likely that gestures played a role

• In 2007, research with bonobos and chimpanzees in captivity showed that they use manual gestures of their hands, feet and limbs more flexibly than facial expressions and vocalizations

• One gesture can communicate different messages in different social contexts

• There may have been several intermediate steps been several intermediate steps between the gestural and vocal communication of apes and human speech

gestural communication in orangutans

if received just part of the goal (food) they gestures more, showing that they were using gestures to communicate a specific goal and to change the actions of the person being gestured to

Why did language evolve?

Language is an adaptation: both the cognitive capacities that allow for language & language itself have been shaped by natural selection

• whatever advantage language conferred was important since:

  • All modern human societies have fairly complex language (word categories, syntax, grammar)

  • Most individuals use language competently

  • People do not have to be taught how to speak

What is culture?

That complex whole high includes knowledge, belief, art, morals, custom, and any other capabilities and habits acquired by an as a member of “society”

Behavior that is transmitted repeatedly through social or observational learning to become a population-level characteristic

culture examples in animals

• dialects in song birds

• Sweet potato washing in Japanese macaques

primates w/ cultural traditions

capuchin traditions

• Eyeball poking

to “prove” culture traits behaviors must

• not be explained by genetic differences

• Not be explained by differences in ecology

culture in chimps

• 7 sites, 151 yrs of observation (additive)

• Behaviors present at some sites but not others

• 39 behaviors categorized as cultural

  • No ecological explanations

example of cultural tradition

ant fishing

• found in mahale

• But not Gombe

  • Same chimp sub-species = not genetic

  • Same ant species in both places = not be explained by differences in ecology

Nut-cracking

• west Africa

• 4,300 yr old chimp tools

do all chimp populations have traditions?

Yes! The longer the study, the more traditions recorded

culture in orangutans

• similar methodology as Whiten study w/ chimps

• 6 sites

• Behaviors present at some site but not others

• 24 behaviors categorized as cultural

  • No ecological explanations

Ex: le carrying to repel mosquitos

bonobo & gorillas in the wild

don’t have any tool use

Nessie example

species found and eaten both at Susan and Gunung Palung

• only use tools at Suaq

What can we learn by studying culture in other species?

• what causes cultural innovation?

• How are cultural traits spread?

• Innovation s the 1st step

no mother is the mother of invention

rehabilitant orangutans show more innovation than wild orangutans

types of innovations

Subsistence = food

Comfort

Signal/social

• pretty similar results in both orangutans & chimps

The ratchet effect hypothesis

• cumulative cultural change

• Beneficial modifications to existing habits can accumulate over time

• What role does learning or imitation play?

How is culture passed on through learning?

Observational learning

• increasing conceptual complexity

  • Mimicry

  • Emulation

  • True imitation