Feder Chapter 4

The Human Lineage

Overview 1

• Chapter 4’s focus is the establishment of the human lineage as reflected in the evolution of the

hominin species Homo erectus.

• The origin of Homo erectus correspond roughly with the peak of the early Pleistocene Epoch, a

period during which the Earth’s temperature declined and large swaths of the higher latitudes and

higher elevations were covered with thick layers of ice called glaciers.

• As a result of so much seawater being tied up in long-lived ice fields, worldwide sea level

declined by more than 100 meters, altering the configuration of the world’s coasts.

• Large areas of land, previously and currently underwater, became exposed and suitable for

plant, animal, and human life.

• Since the early hominin fossils have been found only in Africa, it seems that hominins were

restricted to this continent for as long as 5 million years.

• The later, more widely dispersed hominins were larger, more committed to a terrestrial habitat

and used elaborate stone tools.

• How to classify these species remains a debate! [Anyone surprised by this statement?]

• There is some variation among the different geographic groups.

• Even so there is less variation than we saw in the australopithecines we talked about in the

previous chapter.

• The taxonomic debate is over how many species are represented, but all agree they are from

the genus, Homo.

• Culturally, a new tool tradition appears: Acheulian.

• First appears about 1.7-1.6 mya, after the new hominins dispersed out of Africa.

• The Acheulian tool tradition is found in Africa, Asia, and also Europe.

Overview 2

• The chapter begins with a discussion of a specimen from Nariokotome, Kenya

(called WT15000 and also Turkana Boy; 1.55 mya):

• Nearly complete skeleton; young male was found in 1984

• The development of his teeth were used to estimate his age at12 years

• Others suggest he is younger, 8 years, if one accepts a faster rate of maturation.

• Height was 5’ 3”, but some researchers suggest it would have been more than 6

feet tall if it had survived.

• Post-cranial bones look very modern, but not exact.

• Some researchers see enough differences in the African forms of Homo erectus to

place them into a separate species from the European and Asian fossils.

1. They suggest Home erectus is found only in central and eastern Asia.

2. In southern Europe at Ceprano, central Italy is a find that dates to 900-800,000

years ago.

• Cranial morphology is very close to Homo erectus.

• Researchers suggest a new species for the Italian finds. The discoverers are

calling it Homo antecessor.

3. According to the splitters, the proposed name for the African form is Homo

ergaster.

• I agree with the text, that we should lump Homo antecessor and Homo ergaster in

with Homo erectus for now, at least.

• Lordkipanize et al. found the variation between specimens to be within the

range found in modern apes.

• They can be considered geographic variants of a single species.

Turkana Boy

Evolution of Homo erectus: Two Models

Homo erectus• Sometime after 1.8 million years ago, Homo habilis was replaced by a new hominin

species, Homo erectus.

• This date is attached to specimen ER 3733, Koobi Fora, Turkana Lake. It dates to

about 1.78 mya.

• It is both human, and yet different.

• H. erectus possessed a larger brain than habilis; its mean brain size of just under

1,000 cc is two-thirds the modern human mean.

• With its larger brain and attendant greater intelligence, Homo erectus was able to

adapt to the changing environmental conditions posed by the Pleistocene epoch.

• Body size

• Anthropologists estimate that some Homo erectus adults weighed well over 100

pounds, with an average adult height of about 5 feet 6 inches.

• Homo erectus was quite sexually dimorphic (so males may be larger than the 100

pounds)

• Increased height and weight in H. erectus are associated with a dramatic increase in

robusticity. Robusticity remains common going forward until the advent of modern

humans.

• Brain size and shape

• Early Homo had cranial capacities ranging from as small as 500 cm3 to as large as 800

cm3, but Homo erectus had a cranial capacity of 800 to 1,250 cm3, the mean was 960

cm3, .

• Using the mean, this change represents an increase of 37%

• Endocasts suggest the brain was organized with bilateral assymmetry.

• At the same time, Homo erectus sample actually had less encephalization than

later Homo.

Homo erectus 2

• Brain size and shape (continued)

• The occipital region is rounder, but its forehead is

flatter than earlier species.

• Thick cranial bone, large browridges (supraorbital

tori), and projecting nuchal torus (A projection of

bone in the back of the cranium where neck

muscles attach; used to hold up the head)

• The face was flatter (decreased prognathism), but

the supraorbital torus was pronounced.

• Braincase long and low.

• Cranium wider at base, compared with earlier and

later species

• Sagittal keel, a small ridge from front to back along

the sagittal suture, reflects bone buttressing in a

very robust skull, rather than a specific function

• Dentition

• The dentition of Homo erectus is much like that of

Homo sapiens, but the earlier species exhibits

somewhat larger teeth.

• Corresponding decrease in size of the jaw.

• Because the earliest Homo erectus specimens are

found in the same locations as Homo habilis, most

argue that H. habilis is its ancestor. Reconstruction of H. erectus

Hominins Conquer the World 1

• Following the most reasonable trail beyond the borders of Africa, Homo erectus fossils and their

tools are found in Southwest Asia and Eurasia more than 1.7 million years ago, very soon after

they first appeared in Africa. For reasons that are still debated, these African migrants did not

enter into western Europe until later, perhaps about 900,000 years ago.

• Stones first

• The earliest evidence of the migration out of Africa is found at Erk-el-Ahmar, Israel.

• Dated to 1-7-2.0 mya, Oldowan choppers and flake tools were found.

• Then bones

• The Dmanisi hominins (dim’ an esse’ ee) (1.81 mya)

• The discovery of the Dmanisi materials in Republic of Georgia began in the early 1990s.

The remains are the best-preserved hominins of this age found anywhere outside of Africa.

Many suggest they were the first migrants out of Africa.

• In both body and brain size, they look similar to early Homo in Africa.

• They have the long, low braincase, wide base and a thickening along the sagittal midline

(keel).

• Estimated height ranging from 4 feet 9 inches to 5 feet 5 inches, smaller than full H.

erectus specimens from East Africa or Asia. Body proportions, however, similar to H.

erectus (and H. sapiens) and different from earlier hominins.

• The cranial capacity is smaller – the most recent is 546 cm3 , and the largest is only 730

cm3

• The tool tradition resembles Oldowan.

• At discovery was labeled as Homo georgicus, now Homo erectus georgicus.

Dmanisi Skulls

• Remember the discussion about the lumpers and splitters?

• These Dmanisi skulls demonstrate great intraspecies variation.

• Shows how hard it can be to determine a new species in the fossil record.

• While human evolution was “bushy”, sometimes it was just not.

What else should we lump?

Source: https://media4.s-nbcnews.com/j/streams/2013/october/131017/8c9411406-131017-coslog-skulls3-930a.nbcnews-ux-2880-1000.jpg

Dmanisi Skulls1-5

Hominins Conquer the World 2

• Then bones (continued)

• East Asia

• Eugene Dubois was the first to organize a hunt for fossils in

Indonesia. He first looked at Sangiran, Java.

• In 1891 along the Solo River near Trinil, Java he found

the famous skullcap. Cranial capacity of about 940 cm3.

• The Trinil site dates from 430-540 kya.

• He called this find Pithecanthropus erectus. Renamed as

Homo erectus erectus.

• Major finding: Bipedalism preceded larger brain (big

issue in the day).

Trinil caldarium (skullcap)

• Six sites in eastern Java have yielded all the H. erectus fossil remains found to date from 1.6

mya to 1 mya, during the Early to Middle Pleistocene.

• Oldest Java fossils are close to 1.75 million years old. This date is from a juvenile found at

Mojokerto, Java.

• Confirmed to exist on Java as recently as 100 kya. But, some suggest a very late survival in

Java, where the most recent H. erectus fossils (called the Ngandong individuals) may be as

young as 53-27 kya (Would make it contemporary with modern humans; dating is

controversial)

• New finds, yet to be dated, may change these numbers (See this 2011 article that negates the

recent date).

• Few artifacts and so behavioral data are sketchy here.

FYI: Sangiran Ealey Man Museum is found on Java

Hominins Conquer the World 3

• Then bones (continued)

• China and India

• In China, the oldest evidence are stone cores and flakes at Majuangou site. Located in north-

central China, the site dates to 1.66 mya.

• This date suggests that Homo erectus pekinensis (once Sinanthropus pekinensis)had migrated

here within 200 ky of appearing in Africa.

• This site would have been cold; cultural adaptations to the weather must have occurred.

• Zhoukoudian (Zhoh’ koh dee’ en)

• The fossil remains of H. erectus discovered in the 1920s and 1930s, as well as recent

excavations at Zhoukoudian are the largest collection of H. erectus anywhere.

• The hominin remains belong to approximately 45 adults and children.

• The fossils have typical H. erectus features: a supraorbital torus in front and a nuchal torus

in back, a protruding face, and the skull is broadest near the bottom

• Recent new date places the site at 770 kya at Locality 1 (where Peking Man was found).

• Many of the bones have been lost as they were mistaken to be dragon bones and ground

up for medicines. A young geologist, Pei Wenshong, brought some Zhoukoudian fossils

to anatomist Davidson Black.

• Later Franz Weidenreich took over for Black.

• After WWII began, Weidenreich decided to move the fossils for safety.

• He did take plaster casts before moving them.

• They were handed over to the US Marines and have never been seen again, because

the marines were captured by the Japanese.

Hominins Conquer the World 4

• Then bones (continued)

• Europe

• In addition to the recent finds at Dmanisi, in northern Spain (Atapuerca regions) there are other

important European finds

• Sima del Elephante (dated to 1.2 mya)

• Date makes this site the oldest in western Europe

• Morphology appears to be similar to Dmanisi finds

• Tools and animal bones found; some of the bones have indication of butchering

• Solana del Zamborino and Estrecho del Quipar (760-900 kya)

• No human remains, but evidence of handaxe production is apparent.

• These tools are among the oldest in Europe.

• Gran Dolina (>800 kya, maybe 1 mya)

• At Gran Dolina, more sophisticated tool use, perhaps earliest in western Europe

• Click here to read more.

• New paper (2012) suggests that the Gran Dolina fossils exhibit morphological traits later

linked to Neadertals (Neanderthals). This data suggest these traits developed earlier in

Europe than first thought.

• In southern Europe at Ceprano, central Italy is a find that dates to 900-800,000 years ago.

• Cranial morphology is very close to Homo erectus.

• Researchers suggest a new species for the Italian finds. The discoverers are calling it

Homo antecessor.

• After 400 kya, the fossil record fills up with fossils and interpretations get even more complex!

Ice Coverage During Pleistocene Glacial Maxima

The Age of Ice 1

• Homo erectus was able to adapt to the changing environmental conditions posed by the Pleistocene

epoch (2.6-0.01 mya or 10 kya).

• The Ice Age

• The hominins about which we will be talking this chapter lived during the Pleistocene. Here we

will begin using kya (thousand years ago, rather than just mya).

• We will use these geological terms: the Middle Pleistocene (780 kya-125 kya) & the Upper

Pleistocene (125–10 kya).

• Archaeologically, we will look at the late Lower Paleolithic and the Middle Paleolithic. This

later cultural period:

• Began roughly 30,000–40,000 ya and ending about 10 kya.

• Distinguished by major technological innovations, the creation of the earliest human art

widely recognized as such, and many other accomplishments.

• Is best known from western Europe, similar industries are also known from central and

eastern Europe and Africa.

• During this time there were massive advances and retreats of glaciers (glaciation events).

• Of course, this means that the temperature fluctuated with these shifts.

• Terminology:

• Glaciations were the periods during which the ice sheets covered much of the northern

continents. Within glaciations were more minor fluctuations: 1) stadials: Short periods of

increased glaciations and 2) interstadials: Short periods of decreased glaciations

• Interglacials: When temperatures rose for longer periods than in interstdials and glaciers

receded.

The Ice Age 2• The Pleistocene (continued)

• The most traumatic effects of glaciation were felt in Europe and

in northern Asia (less in southern Asia and Africa).

• In Eurasia

• Interglacials in northern latitudes were associated with

warmer temperatures.

• During glaciation events, migration routes were also

affected as ice sheets advanced, sea levels lowered and

parts of northern areas became uninhabitable.

• In Africa

• Climates did fluctuate, mostly as a result of rainfall

changes.

• In southern latitudes the climate becomes wetter during

interglacials.

• When there was glaciation, it was more arid in Africa;

during the interglacials, it was wetter.

• Food resources were affected.

• Migration routes swung as the Sahara expanded and

blocked the migration in and out of sub-Saharan Africa.

• The pictures at the right illustrate these effects in Africa.

The Ice Age 3

• The oxygen isotope curve

• The oxygen isotope curve allows for the

reconstruction of fluctuations in worldwide glacial

coverage.

• The Shackleton-Opdyke curve.

• Based on oxygen isotope analysis, orange segments

are warm periods (interglacials), and blue segments

are colder with geographically widespread glacial

coverage (glacials) for approximately the last

800,000 years.

• In comparison to interglacials and interstadials,

during glacials and stadials, the amount of 18O in

the shells of foraminifera proportional to the

amount of 16O is higher.

• Over the last 780 kya there have been 10 drops

in 16O (> in 18O).

• This means there were 10 periods of colder

climates.

• Other research suggests an additional 10 such

periods in the first half of the Pleistocene (2.6

mya 1.8 mya).

Homo erectus: The Toolmaker• The first hominins to leave Africa were tool-assisted scavenger-gatherers who

carried the basic concepts and technological capacities of the Oldowan tool

industry.

• The stone tool industry of Homo erectus involving the production of

symmetrical, sometimes artfully rendered handaxes is called Acheulean.

• Making the Acheulian handaxe is not easy, as compared to Oldowan tools.

• The Acheulian (Acheulean) tradition became the general standard.

• It began as early as 1.76 mya at Lake Turkana, Kenya, spread across many

parts of the temperate to tropical parts of Europe and Asia, and ended

roughly 200,000 ya.

• This is a Lower Paleolithic stone tool industry that includes bifacially

(flaked on both sides). worked hand axes and cleavers and many kinds of

flake tools.

• It represents several new concepts:

1. Is a bifacial tool.

2. Uses a new tool-making technique: ‘soft-hammer’ percussion with the

striking tool made of wood, antler or bone.

3. Appears they were communicating ideas about how to make the tools with

others, based on the widespread form and design.

• What is called by many the Acheulian hand ax is the iconic tool of the day.

• Even so, there were other tool types; a much great diversity than the “Swiss

army knife” motif of Oldowan tradition.

• Included cleavers and flake tools for instance.

Hand ax

Soft-hammer

Subsistence

• The accumulated evidence suggests that Homo erectus subsistence was

based on a mixture of scavenging, hunting, and gathering wild plants

foods.

• Archaeological evidence for hunting by Homo erectus includes:

• Animal bones with stone tool cutting marks.

• At Boxgrove Quarry, England, for instance, 4 butchered rhinos were

found with butcher marks and 150 hand axes. These date to around

500 kya, at one time the oldest found in England.

• Similar evidence at Aridos 1 and 2, Spain.

• Wooden hunting spears.

• Also at Boxgrove was a horse scapula with a probable spear wound.

• Kathu Pan site in Africa (500 kya) is evidence of use of spear shafts

in the stone tools being made.

• At Schöningen, Germany, 6 wooden spears were discovered.

• Dating to about 300 kya.

• Found with other wooden tools and associated with bones of

horses and other big game. The fossils have butchery marks.

• Stone cutting tools that would have been useful in butchering.

• Non-meat portions of the diet are documented at site (GBY) in Israel.

• There is pitting on many of the stones recovered.

• Experimental archaeology suggests these were made by hammering

nuts to open them.

Control of Fire

• The question is not whether hominins took advantage of naturally occurring fire, that is

really going to be hard to document.

• Using fire and controlling fire are two separate questions.

• How to determine when humans took advantage of fire in their world, as compared to

controlling is huge question

• The question is when they controlled fire.

• There has been a series of sites suggested to the candidate for first control of fire.

• Among the best documented, and least challenged, has been Gesher Benot Ya'aqov,

Israel, dating to 790 kya.

• Breaking news: April 2012, paper reports a date of 1 mya at Wonderwerk Cave, South

Africa. Strong evidence includes:

• Burned grasses, leaves and bones, were 30 meters back from cave entrance which

decreases the chance of blow-in

• The burning was done repeatedly

• Advantages of fire control include: Warmth, cooking of foods makes them more

eatable/safer, fire-hardening of weapons, some stone flakes better after heating, predator

control, and light

• In 2010, an interesting popular book, Catching fire: How cooking made us human, was

published on the impact of fire.

Homo erectus Art

• The symmetry, balance, precision, and beauty of late Acheulian

handaxes suggests there were more than functional. The

standardization also suggests this.

• In archaeology a raging debate has been on-going.

• Form or function?

• Among all animal species, humans are the only ones known to

possess the ability to create art, and then also the compulsion

to create art.

• Homo erectus, with 2/3 of modern brain size appears to have

had an aesthetic skill.

• In the journal, Nature, in 2014, an article appeared: “Homo

erectus made world's oldest doodle 500,000 years ago”.

• Found on a shell at Trinil was a zig-zag pattern.

• May be evidence of early art in the form of incised lines.

Bilzingsleben site (370 kya)

• Remains of 3 Homo erectus individuals have been found.

• One elephant tibia has incised marks that some suggest is an example of time-keeping.

• Why the earlier dates are particularly important is that they challenge the concept of a “Great

Leap Forward” dating to only 50 kya.

• This is the idea that our brains rewired at this late date based on explosion of technology and

art.

• But these earlier dates so the cognitive changes were earlier.

The Hobbit

• By 25,000 humans had dispersed all over the Old World and

seemed to have it to themselves.

• Then, out of no-where it seemed, finds from Liang Bua Cave,

Flores, Indonesia challenged the common wisdom. Watch this video

clip.

• In late 2004, reports of an incomplete female (LB1) and pieces of

13 other persons were reported.

• Nicknamed ‘hobbits’ , but the formal name is Homo floresiensis

• Feder suggests dates from 100-60 kya.

• The incomplete skeleton of a female (LB1), along with fragments

of 13 other individuals was found.

• LB1 was estimated to 3 feet, with a cranial capacity of only

417 cm3! She has since been nicknamed the “Little Lady of

Flores” and as “Flo”. Size may be the result of insular

dwarfing.

• Where did they originate?

• Suggestion 1: Early Homo migrated out of Africa and that this

ancestral migration may have been earlier than even Homo

erectus.

• Suggestion 2: Physically they resemble Dmanisi Homo erectus,

but there are some derived traits that set them apart (including the

wrist bones).

Homo floresiensis

Reconstruction

Raising Homo erectus

• Full-term human babies are “premature”, unless the young of other

species.

• Physically humans are born at an earlier stage of development

(altricial)

• They remain immature for longer (secondarily altricial).

• But newborns exhibit precocial abilities for sensory and brain

development.

• This would seem to be a dangerous strategy; birthing completely

helpless offspring, who remain helpless for a long period.

• The female pelvic outlet of a biped is narrower.

• The average birth for a chimpanzee is 2 hours, for a human it is 14

hours.

• Further, there is stabilizing selection for size of newborns, low

birth weight and high birth weight offspring are less likely to

survive. Both the newborn and mother not likely to survive if

newborn is high birth weight.

• Selection for females with broader pelvic outlets occurred (most

women really do “run like a girl”).

• The earlier timing of birth in humans allowed for the head to be

smaller. Newborn humans have a smaller head/body ratio than other

primates.

• Typical of apes and humans is neoteny, the “holding on” of traits

similar to those seen in newborn chimps. One reason for this is that,

genetically, it may have aided brain development.

Where are the Hand axes?

• The Acheulian handaxe appears in Africa about the same time as Homo erectus. Interestingly, the

“signature” tool of Homo erectus is missing in many fossil sites.

• It is absent from Dmanisi and Java.

• It appears in China after 1mya, albeit rarely.

• Why did they not take this tool with them as they left Africa?

• Suggestion 1: They could have expanded BEFORE developing handaxe technology, but the

technology came in another wave(s) of migration.

• Suggestion 2: They could have expanded BEFORE developing handaxe technology, and the hand

axes in east Asia are an independent invention.

• Suggestion 3: Perhaps they are there, but not yet found.

• Suggestion 4: Homo erectus is an Asian species, that migrated to Africa and developed handaxes

then.