Human Evolution

Background Info Paleanthropologist: Scientist who studies fossil evidence of human evolution Hominid: Humans and immediate ancestors Scientists study clues from hominids to construct what we know about human evolution

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

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

Primate Family Tree Orangutan Crown lemur

Evolution of Bipedalism Anatomical changes Neck (1) Spine aligned strait down Chest (2) Lower back (3) Human spine is S shaped which allows upright standing hips and pelvis (4) Supports Organs thighs (5), knees (6), feet (7) Shorter toes, alligned feet, knees close together

Pre-hominid Evolution 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 Reconstruction of Australopithecine

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

Homo habilis 612 cc brain 2.3 - 1.6 mya first toolmaker, stone “handy human” brow ridge probable meat-eater possibly arboreal discovered in 1960 by Leakeys Had region of the brain that was essential for speech Artist’s representation of a Homo habilis band as it might have existed two million years ago.

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. H. erectus was considerably taller (5’ 7” 12 yr old) and had a larger brain than H. habilis.

Homo erectus 1891 - Eugene Dubois discovers H. erectus in Java Dubois calls it Pithecanthropus erectus initially, also dubbed “Java Man” dates from 1.9 mya 994 cc brain size (compare to 612 for H. habilis, two-thirds that of modern human) Thick Skull, Large Brow ridges, low forehead, large teeth Hunters, used fires, lived in caves Photograph of Nariokotome boy, an early Homo erectus found near Lake Turkana, Kenya.

Homo erectus – 1.9mya to 27k BP 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 discovered in the Neander Valley (Tal) near Dusseldorf, 1856 massive brain--about 1,400cc on average 5 ft tall, heavy build 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.

Neanderthal 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? Used Tools, carefully shaped stone tools Top: Reconstruction of Neandertal burial from Shanidar cave Bottom: Mousterian tools

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

Cro-Magnon Man Cro-Magnon humans 35,000 years B.P. in western Europe to 17,000 years B.P. 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

Modern Homo Sapiens Humans evolved more or less simultaneously across the entire Old World from several ancestral populations. 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” hypothesis.