HUMAN EVOLUTION— How Did We Get From There to Here?

“The evolutionary design of man has intrigued humans for many years “The evolutionary design of man has intrigued humans for many years. It has lead anthropologists to travel the world in search of fossil evidence to learn who we have evolved from. Human evolution began roughly 5-10 million years ago when the human line split from the apes. Slowly scientists have tried to put the pieces together to give us an idea of our evolutionary line.”

Morphological Evidence for Human Evolution The fossil record shows slow gradual changes in structure over time …  cranium Flattening of face Centering of foramen magnum Reduction in canine size  browridge size  sagittal crest

A E B C D G F ?? Common Ancestor Time H. sapiens Chimp P. boisei A. africanus A. aferensis (“Lucy”) H. erectus H. neanderthalensis H. habilis ?? D B E A G F C Time

Things to Remember … Structural comparisons provide one piece of evidence. Gradual accumulation of traits over time! Modern humans did NOT evolve from apes!! They evolved independently from a common ancestor!! Scientists disagree on the the hominid family tree!!

Common Ancestors in the Primate Family Tree Uncertain ??? Procunsul

Procunsul Common ancestor of anthropoids (monkeys, apes & humans) Most abundant primate during the Miocene Procunsul fossil

Common Ancestor of Chimps & Humans—Missing Link?? Split between apes & humans approx. 5-10 mya Common ancestor likely was small & ”ape-like” with few “human-like” traits Possibly more than one?? Several fossil candidates: “Toumai” ??? “Millennium Man” ??? Identity is still uncertain!! DNA comparisons of gorillas, chimps, and humans predict: Gorillas should split off from the line leading to chimp/humans about 7 to 9 mya Chimpanzees should split off from the human line about 5 to 7 mya

Some of Our Oldest, Most Distant Relatives “Tomai” (6-7 mya) “Millennium Man” (5.7-6.1 mya) Ardipithecus ramidus kadabba (5.2-5.8 mya) Ardipithecus ramidus ramidus (4.4 mya) “Tomai” was discovered in 2002 in a desert in Chad. Sahelanthropus tchadensis, a six-million- to seven-million-year-old find from Chad, is humanlike in having small canine teeth and perhaps a more centrally located foramen magnum (the hole at the base of the skull through which the spinal cord exits), which could indicate that the animal was bipedal. Yet Sahelanthropus also exhibits a number of chimplike characteristics, including a small brain, projecting face, sloped forehead and large neck muscles. It has been nicknamed Toumai, a name often given to children born in the dry season in Chad. Another creature, Orrorin tugenensis, fossils of which come from a Kenyan site dating to six million years ago, exhibits a comparable mosaic of chimp and human traits, as does 5.8-million-year-old Ardipithecus ramidus kadabba from Ethiopia. The earliest unambiguously human fossil, in my view, is 4.4-million-year-old Ardipithecus ramidus ramidus, also from Ethiopia. “Millennium man” bones were discovered in 2000 in Kenya.

AUSTRALOPITHECINE This group is thought to link older hominids (Ardipithecus) to younger hominids (Homo). The transformation from ape-like features to modern human features characterize this group. COUSIN of modern humans—a different branch of the family tree

Australopithecus anamensis Existed from 4.2 - 3.9 mya Discovered by Meave Leakey in East Africa in 1995 Characteristics: Reduced pointy canines Thick tooth enamel More upright posture Fingers long and curved Elongated face Diastema present

Australpethicus afarensis—”Lucy” & Her Family Existed from 3-4 mya Lived in E. Africa Primarily herbivorous May have slept in trees to avoid large predators Characteristics: Small brain (35% modern) Long arms Short legs Upright walker

“Lucy” Discovered by Johanson in 1974 in Ethiopia About 40% of her skeleton was found! She stood about 3'6" tall & likely weighed 62 lbs In 1975 Michael Bush, a student of Johanson's, discovered the fossilised remains of over 13 afarensis individuals buried together in a possible flash flood. The remains show a mixed group of young and old, male and female. The individuals may have been related to each other and the find has been dubbed 'The First Family.'

Laetoli Footprints Found by Mary Leaky in Tanzania These footprints were evidence of bipedalism: Strong heel strike Splayed toes Slight arch

Australopithecus africanus Existed from 2.3-3.0 mya Found in South Africa Characteristics: No saggital crest Less prominent browridge Smaller canines Face less elongated No diastema Ape-like arms

Famous A. africanus Fossils “Taung Baby” 1st Hominid discovered (1924) Child fossil (8 years old) Evidence of African origins “Little Foot” Big toe able to move out to the side Found stashed in a box “Mrs. Ples” Further evidence of African origins Turns out to be “Mr. Ples” 1) "Taung Baby" was found by Raymond Dart in 1924. It was the first hominid found. This was a significant find because it was the first evidence that our origins began in Africa.   2) "Little Foot" was found in Sterkfontein, South Africa by Ron Clark. Clark found this fossil stashed in a box and reassembled it. 3) "Mrs. Ples" was found by Robert Broom. She was conclusive evidence that our origins did indeed begin in Africa. It should also be noted that Mrs. Ples is really Mr. Ples.

Australopithecus garhi Existed 2.5 mya (Ethiopia) Found with many tools and an array of slaughtered animals Characteristics: Canines like Homo genus No diastema Elongated face Ape-like arms and legs Tool use has been the defining criteria that separated the Homo genus from the Australopithecines.

PARANTHROPUS Paranthtropus existed at the same time as the Australopithecines & some species of the Homo. Lived among great predators May have been preyed upon by members of the Homo genus!! Distinguishing features: Robust skulls Large saggital crest Huge flat molars used for grinding COUSIN to modern humans Crest & molars indicate that they were primarily vegetarians

“Nutcracker Man” Paranthropus boisei (1.2-2.3 mya) Open woodlands & grasslands Primarily herbivorous (nuts, seeds, & roots) Lived in harems--1 male & many females Characteristics: Muscular bodies (about 100 lbs) Large, flat face Huge jaw & teeth Thick tooth enamel Small brain (39% modern) Discovered in 1959 by Mary Leakey Huge jaw for chomping tough nuts, seeds, & roots

Paranthropus robustus Existed 1-2 mya Discovered in the 1930’s Australopethecus robustus Named for the heavy build of the fossil Used bones as tools to dig out tubers & termites “Greek Lovers”

HOMO Begins about 2.3 mya Emergence of tool use, language, & culture. Distinguishing characteristics: Bigger brain (above 1000ml) Straight-rising forehead Rounder skull Reduced teeth Shorter arms & longer legs Although HOMO means man, first members (H. habilis) of this group were very “ape-like”

Homo habilis The earliest known Homo Existed from 2.2 to 1.6 mya “Handyman”--avid tool users Scavenger Characteristics: Larger brains (47% modern) Flatter face No browridge Forehead present Long arms brains are about 30% larger than those of A. africanus Small (baseball size), simple tools—Oldowan

Homo rudolfensis Existed from 2.4 to 1.9 mya Omnivorous scavenger Likely competed with H. habilis Characteristics: Larger brains (56% modern) Large body size; very tall (5’5”) No browridge Flatter face Forehead present Long arms brains are about 30% larger than those of A. africanus

Homo ergaster 1.9 mya-600,000 ya “Workman” Lived in desert savannahs Omnivorous scavenger 1st to leave Africa—later became H. erectus Characteristics: Tall & muscular Long legs 74% modern brain size Smooth skin for sweating “Nariokotome Boy” The remains were found to be those of a teenage boy between the ages of 11 and 13 when he died. Around 1.5 million years ago, the boy’s body sank into the marsh where he died and became fossilised. His teeth show signs of an abscess where his milk teeth fell out, indicating that he may have died from septicaemia (blood poisoning).

Homo erectus Lived 2 mya-400,000 ya Fossils found in Africa, Europe, & Asia “Upright man” Used more complex tools (Acheulian) for many tasks & used fire Characteristics: Large brain & thick cranium Sloping forehead Large orbits & face “Turkana Boy”—one of the most complete Homo skeletons

Homo floresensis “Hobbit” May have evolved from Homo erectus Discovered n 2004 on the Indonesian island of Flores 3 ft tall adult female 95,000-13,000 ya Small brain Found w/ stone tools & charred animal remains May have evolved from Homo erectus May have arrived on the island via a boat??

Homo heidelbergensis 500,000-100,000 ya Found in Europe, Africa, India, and China. Used new advanced tools Omnivorous Proficient hunters Characteristics: Muscular, tall (6 feet) Large face & browridge Large brain (90% modern) Big frontal lobes--speech

"Neanderthal Man" H. neanderthalensis 130,000 to 25,000 ya Found in Europe, E. Asia, and the Middle East. Flourished in warm periods & in the Ice Age. Skilled hunters that cooperated to make a kill Relied heavily on meat H. neanderthalensis was found with a more advanced set of Achuelian tools called Mousterian tools. These tools are considered more advanced because more work was put into detailing them with animal bones and horns. Mousterian tools were the first tools to be hafted, that is to have handles. There were 63 different types of these tools.

“Neanderthal Man” Characteristics: Better tools Burial sites with tools, ornaments & flowers Cared for the disabled Clothes & Shelters Culture Art & music (not abstract) H. neanderthalensis was found with a more advanced set of Achuelian tools called Mousterian tools. These tools are considered more advanced because more work was put into detailing them with animal bones and horns. Mousterian tools were the first tools to be hafted, that is to have handles. There were 63 different types of these tools.

"Neanderthal Man" Physical characteristics: Stocky build (5’5”, 200 lbs) Large muscles Long, projecting nose Large brain (12% larger) Extinction likely caused by competition with modern humans Likely not our direct ancestor—DNA analyses shows not closely related

Homo sapiens “Knowing Man” 130,000 ya-Present Found Worldwide Highly crafted tools Complex social organization Omnivorous diet “Cro-Magnon Man” is an early H. sapiens that lived in W. Europe during the late Ice Age Homo sapiens have a characteristic look: their faces are small and tucked under a high, domed braincase. They have small eyebrow ridges and their lower jaw ends in a prominent chin. On average, their bodies are less muscular than those of earlier hominids. The appearance of modern humans coincides with the appearance of highly crafted tools, efficient food-gathering strategies and a complex social organisation. Early modern humans lived in mobile groups and established extensive social networks to trade goods and exchange gifts. These networks probably developed for the purpose of securing future favours when times were hard. And it seems that times were indeed hard for some of the first modern humans. Oldest (130,00 ya) H. sapiens fossil found in Ethiopia.