Albia Dugger Miami Dade College Eldra Solomon Linda Berg Diana W. Martin Chapter 22 (Sections ) The Evolution of Primates

Drs. Mary and Louis Leakey Study Fossil Teeth from Australopithecus Fig. 22-CO, p. 465

Paleoanthropology Fossil evidence from paleoanthropology, the study of human evolution, allows scientists to infer the structure and habits of early humans and other primates Teeth, which have changed dramatically during the course of primate and human evolution – can identify an individual’s species, approximate age, diet, and sex

Origins of Primates Based on fossil evidence, paleontologists hypothesized that the first primates descended from small, shrewlike placental mammals that lived in trees and ate insects Many traits of the 233 living primate species are related to their arboreal (tree-dwelling) past

22.1 PRIMATE ADAPTATIONS LEARNING OBJECTIVE: Describe the structural adaptations that primates have for life in treetops

Primates Primates includes lemurs, tarsiers, monkeys, apes, and humans The first primates appeared by the Early Eocene (56 mya) Several novel adaptations evolved in early primates that allowed them to live in trees

Primate Characteristics Five highly flexible digits, including an opposable thumb (or big toe) used to grasp objects with precision Stereoscopic vision: Eyes in the front of the head allow integration of visual information from both eyes together – important in judging distance and depth perception Relatively large brain, associated with increased sensory input, intelligence, and socialization

KEY POINT: Primate Hands and Feet

Fig. 22-1a, p. 466 HandFoot (a) Lemur (Eulemur mongoz)

Fig. 22-1b, p. 466 HandFoot (b) Tarsier (Tarsius spectrum)

Fig. 22-1c, p. 466 HandFoot (c) Woolly spider monkey (Brachyteles arachnoides)

Fig. 22-1d, p. 466 HandFoot (d) Gorilla (Gorilla gorilla)

KEY CONCEPTS 22.1 Humans are classified in the order Primates, along with lemurs, tarsiers, monkeys, and apes This classification is based on close evolutionary ties

22.2 PRIMATE CLASSIFICATION LEARNING OBJECTIVES: List the three suborders of primates and give representative examples of each Distinguish among anthropoids, hominoids, and hominins

Classification Order Primates Suborder Prosimii (lemurs, galagos, and lorises) Suborder Tarsiiformes (tarsiers) Suborder Anthropoidea or anthropoids (monkeys, apes, and humans)

Tarsiers Nocturnal primates found in rain forests of Indonesia and the Philippines Fig. 22-3, p. 468

Suborder Anthropoidea Anthropoid primates arose in Africa or Asia during the Middle Eocene epoch (45 mya) The oldest anthropoid fossils (Eosimias), found in China and Myanmar, were small, insect-eating arboreal primates that were active during the day One significant difference between anthropoids and other primates is the size of their brains

New World and Old World Monkeys New World monkeys (in South and Central America) Arboreal; some have prehensile tails Include marmosets, capuchins, howler monkeys, squirrel monkeys, and spider monkeys Old World monkeys (in Africa, Asia, and Europe) Some are arboreal; none have prehensile tails Ground dwellers are quadrupedal Include baboons, macaques, guenons, mangabeys, langurs, and colobus monkeys

New World and Old World Monkeys

Fig. 22-4a, p. 468 (a) New World monkey. The white-faced monkey (Cebus capucinus) has a prehensile tail and a flattened nose with nostrils directed to the side.

Fig. 22-4b, p. 468 (b) Old World monkey. The Anubis baboon (Papio anubis) is native to Africa. Note that its nostrils are directed downward.

Hominoids hominoids A group composed of apes and hominins (humans and their ancestors; also called hominids) A cat-sized, forest-dwelling arboreal monkey with a few apelike characteristics, Aegyptopithecus, lived during the Oligocene epoch (34 mya) Apes and Old World monkeys diverged 25 mya to 23 mya

Hominoids (cont.) The oldest fossils with hominoid features (Proconsul) appeared about 20 mya Dryopithecines (Dryopithecus, Kenyapithecus, Morotopithecus), apes that lived about 15 mya, may have given rise to modern apes as well as to humans Five genera of hominoids exist today: gibbons (Hylobates), orangutans (Pongo), gorillas (Gorilla), chimpanzees (Pan), and humans (Homo)

Primate Evolution

Fig. 22-2, p. 467 Suborder Prosimii Suborder Tarsiiformes Suborder Anthropoidea (Anthropoids) Hominoids Lesser ApesGreat Apes New World monkeys Old World monkeys LemursTarsiers GibbonsOrangutans Gorillas ChimpanzeesHumans Common hominoid ancestor Common anthropoid ancestor Common primate ancestor

ANIMATION: Primate evolutionary tree To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

Ape Evolution

Fig. 22-5a, p. 469 (a) Fossils of Aegyptopithecus, a fairly primitive anthropoid, were discovered in Egypt.

Fig. 22-5b, p. 469 (b) Skeletal reconstruction of Proconsul. (The reconstructed parts are white.) This anthropoid had the limbs and body proportions of a monkey but lacked a tail, like all apes.

Fig. 22-5c, p. 469 (c) Dryopithecus, a more advanced ape, may have been ancestral to modern hominoids.

Ape Locomotion Gibbons and orangutans are tree dwellers (can brachiate) Chimpanzees and gorillas have adapted to life on the ground; they use their long arms to assist in quadrupedal walking (knuckle walking) Like humans, apes lack tails, which makes them easy to distinguish from monkeys

Apes

Fig. 22-6a, p. 470 (a) A mother white- handed gibbon (Hylobates lar) nurses her baby. Gibbons are extremely acrobatic and often move through the trees by brachiation.

Fig. 22-6b, p. 470 (b) An orangutan (Pongo pygmaeus) mother and baby. Orangutan anatomy is adapted to living in trees.

Fig. 22-6c, p. 470 (c) A young lowland gorilla (Gorilla gorilla) in knuckle-walking stance. Gorillas spend most of the day eating plants.

Fig. 22-6d, p. 470 (d) A mother bonobo chimpanzee (Pan paniscus) holds her sleeping baby. Bonobos are endemic to a single country, the Democratic Republic of Congo.

Molecular Data The amino acid sequence of chimpanzee hemoglobin is identical to that of humans; gorilla and rhesus monkey hemoglobins differ from humans by 2 and 15 amino acids Orangutans diverged from gorilla, chimpanzee, and hominin lines about 14 mya Gorillas diverged from chimpanzee and hominin lines 8 mya Chimpanzee and hominin lines diverged 6 to 7 mya

KEY CONCEPTS 22.2 The study of living primates provides clues to help scientists reconstruct the adaptations and lifestyles of early primates, some of which were ancestors of humans

ANIMATION: Primate skeletons To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

22.3 HOMININ EVOLUTION LEARNING OBJECTIVES: Describe skeletal and skull differences between apes and hominins Briefly describe the following early hominins: Orrorin, Ardipithecus, and Australopithecus anamensis, A. afarensis, and A. africanus Distinguish among the following members of genus Homo: H. habilis, H. ergaster, H. erectus, H. antecessor, H. heidelbergensis, H. neanderthalensis, and H. sapiens Discuss the origin of modern humans

The Human Skeleton The human skeleton has distinct features that reflect humans’ ability to stand erect and walk on two feet (bipedal posture) The curvature of the human spine provides better balance and weight distribution for bipedal locomotion In humans, the shape of the pelvis and alignment of toes are adapted for upright walking The foramen magnum is centered in the base of the human skull, positioned for erect walking

Gorilla and Human Skeletons

Fig. 22-7, p. 471 Simply curved spine Foramen magnum at the center base of skull Complex curvature of human spine Foramen magnum at the center rear of skull Tall, narrow pelvis (front view) Shorter, broader pelvis (front view) First toe not opposable, and all toes aligned First toe not aligned with others Gorilla skeletonHuman skeleton

The Human Skull Relative to body size, human brains are much larger than ape brains Modern human skulls lack prominent supraorbital ridges Human faces are flatter than those of apes, and the jaws are shaped differently – humans have smaller teeth

Gorilla and Human Heads

Fig. 22-8a, p. 472 Supraorbital ridge Incisors Rectangular shape (a) The ape skull has a pronounced supraorbital ridge.

Fig. 22-8b, p. 472 Incisors U shape (b) The human skull is flatter in the front and has a pronounced chin. The human brain, particularly the cerebrum ( purple ), is larger than that of an ape, and the human jaw is structured so that the teeth are arranged in a U shape. Human canines and incisors are also smaller than those of apes.

The Earliest Hominins Most paleoanthropologists place Sahelanthropus (6 to 7 mya) close to the base of the human family tree Orrorin is an early hominin that arose about 6 mya Researchers studying the fossil leg bones of Orrorin think that it walked upright and was bipedal Ardipithecus, Australopithecus, and Paranthropus species are often referred to as australopithecines Australopithecines were bipedal, a hominin feature

Australopithecines The first Ardipithecus, A. kadabba, appeared about 5.8 mya Ardipithecus ramidus, which appeared about 4.8 mya, may have given rise to Australopithecus anamensis, which probably gave rise to another primitive hominin, Australopithecus afarensis Many paleoanthropologists think that A. afarensis gave rise to several australopithecine species, including Australopithecus africanus, Paranthropus spp., and possibly Homo habilis

Australopithecus afarensis A remarkably complete 3.2-million- year-old skeleton, nicknamed Lucy, was found in Ethiopia in 1974 by a team led by U.S. paleoanthropologist Donald Johanson Fig , p. 474

Homo habilis and Homo ergaster Homo habilis was the earliest known hominin with some of the human features lacking in australopithecines, including a slightly larger brain Homo habilis fashioned crude tools from stone The best-known fossils of H. ergaster, (2.0 to 1.4 mya) come from Kenya Homo ergaster may be the direct ancestor of later humans

Homo erectus Homo erectus had a larger brain than H. habilis; made more sophisticated tools; and may have worn clothing, built fires, and lived in caves or shelters Homo erectus, probably a later Asian offshoot of H. ergaster, appears to be an evolutionary dead end

Homo erectus Skull from China

Fig , p. 475 Pronounced supraorbital ridge Receding forehead Projecting face/jaws

Acheulean Tool Fig , p. 475

Inquiring About: THE SMALLEST HUMANS In 2004, fossils were found of seven adult humans that were about 1 m (about 3 ft) tall Homo floresiensis p. 476

Archaic Humans Archaic humans are regionally diverse descendants of H. ergaster that lived in Africa, Asia, and Europe 1.2 mya to 200,000 years ago The brains of archaic humans were essentially the same size as our brains, although their skulls retained some ancestral characters – they had rich and varied cultures Some researchers classify the oldest archaic human fossils discovered in Europe as Homo antecessor (1.2 mya to 800,000 years ago)

Archaic Humans (cont.) Homo heidelbergensis (600,000 to 300,000 years ago) may have descended from H. antecessor H. heidelbergensis had a larger brain – similar in size to that of modern humans – than either H. ergaster or H. antecessor Many scientists think that both Neandertals and modern humans descended from H. heidelbergensis

Neandertals Neandertals (250,000 to 30,000 years ago) had short, sturdy builds; receding chins and foreheads; heavy supraorbital ridges and jawbones; large front teeth; and nasal cavities with triangular bony projections Neandertals cared for the aged and the sick, an indication of advanced social cooperation They apparently had rituals, possibly of religious significance, and sometimes buried their dead

Neandertal Tools Neandertal tools (Mousterian tools) were more sophisticated than those of H. erectus Fig , p. 477

The Disappearance of Neandertals The disappearance of the Neandertals about 28,000 years ago is a mystery debated among paleoanthropologists Many scientists think that Neandertals were a separate species, Homo neanderthalensis Analysis of Neandertal mitochondrial DNA (mtDNA) shows that its sequence differs significantly from all modern human mtDNA sequences

Modern Homo sapiens Homo sapiens, anatomically modern humans, existed in Africa about 195,000 years ago By about 30,000 years ago, anatomically modern humans were the only members of genus Homo remaining, excluding small, isolated populations Both recent fossil finds and extensive molecular analyses have promoted the out-of-Africa model as the main explanation for the origin of modern humans

One Interpretation of Human Evolution Fig. 22-9, p. 473

Molecular Anthropology Recent genetic studies compared mtDNA, Y chromosome, and autosomal DNA in present-day populations to ancient DNA extracted from Neandertal and early H. sapiens remains These studies support the case for Africa as the birthplace of modern humans

Human Migrations, Based on Y Chromosome Data

Fig , p. 477 LLY22 M173 M242 M343 M17 M170 M45 M174 M9 M20 M201 M122 M3 M172, M135 M96 M130 YAPM89 M175 M168 M69 M60 Origin M4 M2 M91 M130 M304

KEY CONCEPTS 22.3 Fossil evidence indicates that the earliest human ancestors arose in Africa and shared many features with their apelike ancestors The human brain did not begin to enlarge to its present size and complexity until long after human ancestors had evolved bipedal locomotion

ANIMATION: Genetic distance between human groups To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

ANIMATION: Human evolution, genus homo To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

22.4 CULTURAL CHANGE LEARNING OBJECTIVE: Describe the impact of human culture on the biosphere

Human Culture At the level of our DNA sequences, we are roughly 98% identical to gorillas and 99% identical to chimpanzees Human culture is not inherited in the biological sense but is learned, largely through language Human culture is generally divided into three stages: Development of hunter–gatherer societies Development of agriculture The Industrial Revolution

Development of Agriculture Humans began to cultivate crops about 10,000 years ago, resulting in a more dependable food supply and more permanent dwellings Animal domestication generally followed later, which supplied people with food, milk, and hides In agricultural societies, fewer people are needed to provide food for everyone – agriculture freed some people to pursue other endeavors, including religion, art, and crafts

The Industrial Revolution The Industrial Revolution (18th century) concentrated populations in urban areas near centers of manufacturing The spread of industrialization increased demand for natural resources to supply raw materials for industry The human population expanded so dramatically (6.8 billion in 2009) that there are serious questions about Earth’s ability to support so many people

Humans and The Biosphere Human culture has resulted in large-scale disruption and degradation of the environment Many species cannot adapt to the rapid environmental changes caused by humans and are becoming extinct The decrease in biological diversity from species extinction is alarming

KEY CONCEPTS 22.4 Human culture began when human ancestors started making stone tools