human evolution

Human Evolution: A Summary Modified by Alaine Davis from a presentation by anthropologist Kristina Killgrove, accessed online 01/04/10:

Human Evolution: A Summary Modified by Alaine Davis from a presentation by anthropologist Kristina Killgrove, accessed online 01/04/10

Carl Sagan’s Universe Calendar:

Carl Sagan’s Universe Calendar 24 days = 1 billion years 1 second = 475 years “Big Bang” January 1 Milky Way May 1 Solar System September 9 Life on Earth September 25 Humanlike Primates December 31, 10:30pm Milky Way

Early Primates:

Early Primates Prosimians (65 mya) Monkeys (35 mya) Apes (23 mya) Hominids (5 mya)

Early Primates - Traits:

Early Primates - Traits Common physical primate traits: Dense hair or fur covering Warm-blooded Live young Suckle Infant dependence Common social primate traits: Social life Play Observation and imitation Pecking order Common Primate Traits

Primate Family Tree:

Primate Family Tree Crown lemur Orangutan

Evolution of Bipedalism:

Evolution of Bipedalism Anatomical changes Neck (1), chest (2), lower back (3), hips and pelvis (4), thighs (5), knees (6), feet (7) Theories Tool use and bipedalism (Darwin/Washburn) Energy efficiency and bipedalism (Isbell/Young) Radiator theory (Falk) Body temperature and bipedalism (Wheeler) Habitat variability and bipedalism (Potts) Reproduction and bipedalism (Lovejoy) Canine reduction and bipedalism (Jolly)

Pre-hominid Evolution:

Pre-hominid Evolution Reconstruction of Australopithecine Ardipithecus ramidus 4.4 - ? mya A. anamensis 4.2 - 3.9 A. afarensis 4.2 - 2.5 A. bahrelghazali 3.5 - 3.0 A. africanus 3.5 - 2.5 P. aethiopicus 2.7 - 2.3 A. garhi 2.5 - ? P. boisei 2.3 - 1.3 P. robustus 2.0 - 1.0 Bipedalism Tools Language

Hominid Evolution:

Hominid Evolution Homo habilis (2.0 – 1.6mya) H. rudolfensis (2.4-1.6mya) H. erectus (1.9-27kyBP) H. heidelbergensis (800-100kyBP) H. neanderthalensis (300-30kyBP) H. sapiens (130kyBP – present) Scale: Millions of Years BP

Hominid Evolution:

Hominid Evolution Major Homo advances: Brain size Better bipedalism Hunting Fire ( H. erectus ) Tools ( H. habilis ) ( H. erectus ) ( H. heidelbergensis ) ( H. sapiens ) Built shelters ( H. heidelbergensis ) Clothing ( H. neandertalensis ) Language (Neandertals?)

Homo habilis:

Homo habilis Artist’s representation of a Homo habilis band as it might have existed two million years ago. 612 cc brain 2.3 - 1.6 mya first toolmaker prognathic face, brow ridge probable meat-eater possibly arboreal discovered in 1960 by Leakeys no speech

H. habilis v. H. erectus:

H. habilis v. H. erectus Finds in east Africa indicate that Homo habilis was not very different from the australopithecines in terms of body size and shape. The earliest Homo erectus remains indicate rapid biological change. The fossil record for the transition from H. habilis to H. erectus supports the punctuated equilibrium model of evolution. H. erectus was considerably taller and had a larger brain than H. habilis .

Homo erectus:

Homo erectus 1891 - Eugene Dubois discovers H. erectus in Java Dubois calls it Pithecanthropus erectus initially, also dubbed “Java Man” finds in China called Sinanthropus dates from 1.9 mya to 27,000 ya 994 cc brain size (compare to 612 for H. habilis ) More sophisticated tool use Photograph of Nariokotome boy, an early Homo erectus found near Lake Turkana, Kenya.

Homo erectus – 1.9mya to 27k yBP:

Homo erectus – 1.9mya to 27k yBP Why was H. erectus so successful? Less sexual dimorphism = possible pair bonds, marriage Less hair on body = wearing of furs, other clothing Wearing of furs = ability to live further north Quick adaptation to environment without physical changes Culture is main reason H. erectus was so successful organization for hunting ability to protect against predators control of fire? possible campsites tools Distribution of H. erectus

Homo neanderthalensis:

Homo neanderthalensis discovered in the Neander Valley (Tal) near Dusseldorf, 1856 massive brain--about 1,400cc on average large torso, short limbs, broad nasal passages later remains show decrease in robustness of the front teeth and face, suggesting use of tools replaced teeth The skull of the classic Neandertal found in 1908 at La Chapelle-aux-Saints.

Neandertal Culture:

Neandertal Culture Homesites – In caves, also in the open (near rivers, framed with wood and covered with skins) Burial – Is there evidence of purposeful burial and ritual? Language – Could Neandertals talk or not? Tools – mainly made of flint Top: Reconstruction of Neandertal burial from Shanidar cave Bottom: Mousterian tools

What happened to Neandertals?:

What happened to Neandertals? H. neanderthalensis coexisted with H. sapiens for at least 20,000 years, perhaps as long as 60,000 years What happened? Neandertals interbred with H. sapiens Neandertals were killed off by H. sapiens H. sapiens drove Neandertals into extinction by competition

Homo sapiens:

Homo sapiens Archaic – 100,000 to 35,000 ya Sometimes called Homo sapiens and Homo sapiens neanderthalensis Modern – 35,000 ya to present Anatomically modern Sometimes called Homo sapiens sapiens

Biological Classification of Modern Humans:

Biological Classification of Modern Humans Kingdom: Animalia Phylum/Subphylum: Chordata/Vertebrata Class: Mammalia Order: Primata Suborder: Anthropoidsae (humans, apes, monkeys – not lemurs, tarsiers) Superfamily: Hominidiae (humans, apes, chimpanzees) Family: Homininae (human ancestors and us, including Lucy) Genus: Homo Species: sapiens

Cro-Magnon Man:

Cro-Magnon Man Cro-Magnon humans 35,000 ya in western Europe to 17,000 ya 1,600 cc cranial capacity Name comes from a hotel in France Not a different species, just old Homo sapiens from Europe Artist’s reconstruction of a Cro-Magnon man

Archaic H. sapiens Culture:

Archaic H. sapiens Culture Art Traces of art found in beads, carvings, and paintings Cave paintings in Spain and southern France showed a marked degree of skill Female figurines 27,000 to 22,000 ya Called “venuses,” these figurines depicted women with large breasts and broad hips Perhaps it was an example of an ideal type, or perhaps an expression of a desire for fertility

Archaic H. sapiens Culture:

Archaic H. sapiens Culture Cave paintings Mostly animals on bare walls Subjects were animals favored for their meat and skins Human figures were rarely drawn due to taboos and fears that it would somehow harm others Cave paintings from 20,000 years ago at Vallon-Pont-d’Arc in southern France (left) and from Lascaux, in southwest France

Upper Palaeolithic – Hotbed of Culture:

Upper Palaeolithic – Hotbed of Culture 40,000 – 10,000 ya Shelters 15,000 ya Ukraine Some made with mammoth bones Wood, leather working; carpentry Tools From cores to blades Specialization Composite tools Bow and arrow Domestication of dogs Gathering rather than hunting became the mainstay of human economies. Top: Straw Hut Left: Mammoth bone hut Bottom: Tool progression

Modern Homo Sapiens:

Modern Homo Sapiens Regional-Continuity Model (Milford Wolpoff, UMich) Humans evolved more or less simultaneously across the entire Old World from several ancestral populations. Rapid-Replacement Model (Chris Stringer, NHM London) Humans evolved only once--in Africa from H. heidelbergensis ancestors--and then migrated throughout the Old World, replacing their archaic predecessors. Also called the “Out of Africa” and “Killer Ape” hypothesis.

Social Organization:

Social Organization Hunter-gatherer analogy Small group, low population density, nomadism, kinship groups Migration North America was the last colonized by hominids. Beringia (land bridge) between Russia and Alaska Asian origin of Native Americans 30,000 to 12,000 ya was first migration

Piltdown Man:

Piltdown Man In 1912 a skull and jawbone with teeth were collected from a gravel pit in Piltdown, a village in England. Scientists claimed it was a new species and proved that the first humans evolved in Europe, not Africa. This reflected the cultural biases of Europeans of the time. Information from Wikipedia, accessed 01/04/10

Slide 26:

“Piltdown Man” was exposed as a hoax more than 40 years later. This was not a real species but the lower jawbone of an orangutan, teeth of a chimpanzee and the skull of a modern human that had been treated with chemicals to appear very old, then deliberately combined and planted in the dig site. The main suspect was the “discoverer”, Charles Dawson. He died several decades before the fraud was exposed.