KINGDOM: ANIMALIA PHYLUM: CHORDATA CLASS: MAMMILIA PRIMATE ORIGINS KINGDOM: ANIMALIA PHYLUM: CHORDATA CLASS: MAMMILIA 160 MILLION YEARS AGO: The First Placental Mammals…

PANGEA

DINOSAURS DOMINATE MAMMALS LURK! TRIASSIC JURASSIC CRETACEOUS MESOZOIC ERA 250-65 Million Years B. P. Continental Drift: Breakup of Pangea: Laurasia & Gondwana The First Placental Mammals – Subclass Eutheria Mesozoic Era, Jurrasic Period, 160 Million Years Before Present

JURMAIA, JURASSIC EPOCH, CHINA

MAMMAL CHARACTERISTICS Vertebrates Heterodontic Cerebrum (Enlarged Forebrain) Warm Blooded (Homeothermic) Live Birth Nurture Their Young

CENOZOIC ERA Dinosaurs Die; Mammals Take Over! PALEOGENE: 65-23 Million Years B. P. NEOGENE: 23 Million Years B. P to Present Continental Drift: Breakup of Laurasia & Gondwana Chixalub Meteor Deccan Traps Eruption

PRIMATE CHARACTERISITICS Mammals with Prehensile (Grasping) Hands/Feet Nails instead of Claws Enlarged Pads on Digits Generalized Structure Binocular Stereoscopic Vision Large Brain to Body Ratio PROSIMIANS AND ANTHROPOIDS

PALEOGENE PERIOD PRIMATES PALEOCENE: 65 – 56 Million Years B. P. Carpolestes simpsoni (Primate-Like Mammal) EOCENE: 56 – 34 Million Years B. P. Adapis (Early Primate) OLIGOCENE: 34 – 23 Million Years B. P. Aegyptopithicus (Early Anthropoid)

THE FIRST PRIMATES Carpolestes simpsoni: Fruit-Eating Primate-Like Mammal

Adapis Prosimian-Like

The First Anthropoids Monkey-like Aegyptopithicus

Proconsul An Early Ape

Geological Epochs Miocene: 23 – 5.6 Million Years B. P. Miocene Apes – First Hominoids Pliocene: 5.6 – 1.8 Million Years Early Hominin Radiation Pleistocene: 1.8 – 0.01 Million Years B. P. Evolution of Genus Homo Holocene: 10 Thousand Years B. P. to Present Spread of Domestication, Agriculture

Major Events in Early Primate Evolution

Oligocene Primates from Fayum Aegyptopithecus Largest of Fayum anthropoids, roughly the size of a modern howler monkey (13-18 lbs) Short-limbed, slow-moving Bridges the gap between Eocene fossils and succeeding Miocene hominoids

Pierolapithecus Miocene Epoch Ancestor to all Great Apes? 13 Million Years B. P.

Miocene Fossil Hominoids Asian forms (16–7 mya) The largest and most varied group from Turkey through India/Pakistan and east to southern China, most are highly derived. Sivapithecus

Sivapithecus Compared Comparison of a modern chimpanzee (left), Sivapithecus (middle), and a modern orangutan (right). Both Sivapithecus and the orangutan exhibit a dished face, broad cheekbones, and projecting upper jaw and incisors.

Sahelanthropus tchadensis Miocene Epoch Early Hominin, 5 – 7 Million Years B. P First Bipedal Hominin?

Miocene Hominoid Distribution, From Fossils Thus Far Discovered

Paranthropus aethiopicus Pliocene Epoch Robust Hominid 2.4 Million Years B. P.

Australopithicus afarensis Pliocene Epoch Early Hominin 3.7 – 3.0 Million Years B. P.

Biocultural Evolution All aspects of human adaptation, including technology, traditions, language, religion, marriage patterns, and social roles. Culture is a set of learned behaviors; it is transmitted from one generation to the next through learning and not by biological or genetic means. Material culture is part of the cultural complex

Early Hominin Tools Earliest tools likely made of perishable materials Hominin bipedalism would have made tools easier to transport Oldowan-Earliest recognized stone tool culture, including very simple tools, mostly small flakes

Oldowan tools

Dating Methods Chronometric (Absolute) dating methods are based on calendar years K/Ar, or potassium argon method used to date materials in the 5-1 mya range Carbon-14 method used to date organic material extending back to 75,000 years Thermoluminescence Uranium series dating Electron spin resonance (ESR)

Revised Classification of Hominoids

Mosaic Evolution A pattern of evolution in which the rate of evolution in one functional system varies from that in other systems. In hominin evolution, bipedal locomotion is a defining characteristic; other features such as brain development and behavior become significant in later stages

Mosaic Evolution of Hominin Characteristics Locomotion Modern Homo sapiens Bipedal: shortened pelvis; larger body and legs; fingers and toes not as long Early hominin Bipedal: shortened pelvis; differences from later hominins, smaller body and long arms relative to legs; long fingers and toes; capable of considerable climbing Miocene, generalized hominoid Quadrupedal: long pelvis; capable of considerable arm swinging, suspensory locomotion

Mosaic Evolution of Hominin Characteristics Brain Modern Homo sapiens Greatly increased brain size—highly encephalized Early hominin Larger than Miocene forms, moderately encephalized; prior to 6 m.y.a., no more encephalized than chimpanzees Miocene, generalized hominoid Small compared to hominins, large compared to other primates; a fair degree of encephalization

Mosaic Evolution of Hominin Characteristics Dentition Modern Homo sapiens Small incisors; canines further reduced; molar tooth enamel caps thick Early hominin Moderately large incisors; canines somewhat reduced; molar tooth enamel caps very thick Miocene, generalized hominoid Large front teeth; molar teeth variable, depending on species; some have thin enamel caps, others thick enamel caps

Mosaic Evolution of Hominin Characteristics Toolmaking Behavior Modern Homo sapiens Stone tools found after 2.5 m.y.a.; trend of cultural dependency in later hominins Early hominin In earliest stages unknown; no stone tool use prior to 2.5 m.y.a.; more oriented toward tool manufacture and use than chimpanzees Miocene, generalized hominoid Unknown—no stone tools; probably had capabilities similar to chimpanzees

Walking the Walk: The Bipedal Adaptation Efficient bipedalism as the primary form of locomotion is seen only in hominins. Advantages of bipedalism: Freed the hands for carrying objects and for making and using tools. In the bipedal stance, animals have a wider view of the surrounding countryside. Bipedal walking is an efficient means of covering long distances.

Mosaic Evolution A pattern of evolution in which the rate of evolution in one functional system varies from that in other systems. In hominin evolution, bipedal locomotion is a defining characteristic; other features such as brain development and behavior become significant in later stages

Mosaic Evolution of Hominin Characteristics Locomotion Modern Homo sapiens Bipedal: shortened pelvis; larger body and legs; fingers and toes not as long Early hominin Bipedal: shortened pelvis; differences from later hominins, smaller body and long arms relative to legs; long fingers and toes; capable of considerable climbing Miocene, generalized hominoid Quadrupedal: long pelvis; capable of considerable arm swinging, suspensory locomotion

Mosaic Evolution of Hominin Characteristics Brain Modern Homo sapiens Greatly increased brain size—highly encephalized Early hominin Larger than Miocene forms, moderately encephalized; prior to 6 m.y.a., no more encephalized than chimpanzees Miocene, generalized hominoid Small compared to hominins, large compared to other primates; a fair degree of encephalization

Mosaic Evolution of Hominin Characteristics Dentition Modern Homo sapiens Small incisors; canines further reduced; molar tooth enamel caps thick Early hominin Moderately large incisors; canines somewhat reduced; molar tooth enamel caps very thick Miocene, generalized hominoid Large front teeth; molar teeth variable, depending on species; some have thin enamel caps, others thick enamel caps

Mosaic Evolution of Hominin Characteristics Toolmaking Behavior Modern Homo sapiens Stone tools found after 2.5 m.y.a.; trend of cultural dependency in later hominins Early hominin In earliest stages unknown; no stone tool use prior to 2.5 m.y.a.; more oriented toward tool manufacture and use than chimpanzees Miocene, generalized hominoid Unknown—no stone tools; probably had capabilities similar to chimpanzees

Walking the Walk: The Bipedal Adaptation Efficient bipedalism as the primary form of locomotion is seen only in hominins. Advantages of bipedalism: Freed the hands for carrying objects and for making and using tools. In the bipedal stance, animals have a wider view of the surrounding countryside. Bipedal walking is an efficient means of covering long distances.

Footprints at Laetoli Hominin footprint from Laetoli, Tanzania. Note the deep impression of the heel and the large toe (arrow) in line (adducted) with the other toes.

Australopithecus afarensis

A Transitional Australopith?

Closer Connections: Early Homo (2.0+-1.4 mya) Increased brain size Associations with stone tools

Early Homo Fossil Finds

A Tentative Early Hominin Phylogeny

Seeing the Big Picture What explains the pattern of speciation The evidence is far from complete and significant gaps will remain Patterns are evident Early hominin species had restricted ranges; each species exploited a relatively small range and could easily have become separated from other populations of its own species