McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CONRAD PHILLIP KOTTAK CHAPTER 4 The Primates This chapter introduces students to the study of living, non-human primates. It discusses the basic classification of primates and all of the classes of living primates. It also examines the similarities and differences between non-human primates and humans, as well as the earliest primate species which lived during the Eocene and Miocene.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Our Place among Primates –Key terms Taxonomy: the assignment of organisms to categories. Hominoidea: superfamily containing humans and apes. Phylogeny: genetic relatedness based on common ancestry.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Phylogenetic Classification Organisms are placed in classifications, which are arranged hierarchically according to degree of genetic relatedness. Phylogenetic classification is a descending hierarchy of classifications, from most inclusive to least inclusive. Species are constituted by organisms whose mating produces viable and fertile offspring.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Homologies and Analogies –Homologies are similarities that organisms share because of common ancestry. The presence of homologies is the principal factor in determining how organisms are assigned to taxonomic categories. –Analogies are similarities between species that are the result of similar adaptation to similar selective pressures-- analogies are not the result of common ancestry. The process which leads to analogies is called convergent evolution.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Primate Tendencies –Grasping: precision grip, thumb opposability, nails instead of claws. –Smell to Sight: eye placement, brain organization, and color vision all reflect an emphasis of sight over smell. –Nose to Hand: increasing reliance on sense of touch as opposed to muzzle, whiskers for information.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Brain Complexity: the brain areas devoted to thought, memory, and association are more elaborate and larger. –Parental Investment: single offspring births combined with longer development periods stemming from neotony. –Sociality: strongly associated with parental investment, cooperative social groups are selected for in part because of the needs arising from primate parenting.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Prosimians –Prosimians vs. Anthropoids Prosimians and anthropoids constitute the two suborders of primates. 30 million years ago, prosimians were driven from niches by better adapted anthropoids.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Lemurs and Tarsiers Most of the remaining prosimians are lemurs. Lemurs live only in Madagascar, which separated from Africa prior to the development of anthropoids. Tarsiers survived in Asia by adapting to night conditions.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Anthropoids –Vision Evolutionary changes in vision probably occurred in response to the pressures of an arboreal habitat. Binocular, stereoscopic vision and color vision may have been selected due to the improved depth perception it endows.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –The arboreal habitat (climbing, feeding) and the increasingly social environment (mutual grooming, tool making) were likely factors in selecting for increased manual tactility. –Proportionately larger brain mass and emphasis on memory and cognition were likely selected for by the social environment.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Monkeys –Platyrrhines and Catarrhines There are two anthropoid infraorders: platyrrhines and catarrhines. Unlike hominoids, monkeys’ rear and fore limbs articulate from their bodies as do dogs’.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Platyrrhines: New World Monkeys Traits: universally arboreal, some brachiate, some have prehensile tails. –Catarrhines: Old World Monkeys Old World monkeys are both terrestrial and arboreal. Significant distinctions existing between arboreal and terrestrial Old World monkeys include size and sexual dimorphism.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Apes –Old World Monkeys belong to the superfamily Cercopithecoidea, while humans and apes are in the superfamily Hominoidea. –Hominoidea is subdivided into three families. Hominids (humans and their fossil ancestors) Pongids (“great apes”: gorillas, chimpanzees, and orangutan) Hylobatids (gibbons and siamangs) Recent biochemical evidence suggests that gorillas and chimpanzees are almost as closely related to humans as they are to each other.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Gibbons Gibbons are small, arboreal, mate for life, and produce few offspring. Their principal mode of locomotion is brachiation. –Orangutans Orangutans are relatively large (up to 200 pounds), solitary, and markedly sexually dimorphic. Orangutans move between arboreal and terrestrial habitats. –Gorillas Gorillas are large (up to 400 pounds), the most sexually dimorphic of all primates, and are primarily terrestrial. They live in relatively stable social groups, typically led by a mature silver-back male.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Chimpanzees There are two kinds of chimpanzee: the common (Pan troglodytes) and the pygmy (Pan paniscus). The common chimpanzee is found in western central Africa and western Africa. Size range is up to 200 pounds, and sexual dimorphism is proportionally the same as in humans. Chimpanzee social organization is relatively well- known, because of the longitudinal studies done by Goodall and other primatologists.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Bonobos belong to the species Pan paniscus. live in the humid forests of the Democratic Republic of Congo. communities are female-centered, peace-loving, and egalitarian. frequently use sex to avoid conflict within the community.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Endangered Primates –Humans are the only hominoids that are not endangered. –Deforestation, poaching, and the capture of primates have all contributed to the demise of wild primate populations.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Human-Primate Similarities –Learning Neotony and life in cooperative social groups allow primates to learn behavior from their fellows, rather than relying only on genetically encoded behaviors. –Tools Tools allow primates to adapt to a wider range of niches more quickly than physiological adaptation alone. Wild chimps have been observed constructing tools.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Predation and Hunting Hunting is a regular and normal component of wild chimpanzee behavior. Wild chimpanzees have been observed hunting consistently, using cooperative techniques, with some sex specialization (males hunt more than females). –Aggression and Resources The capacity for hunting exists among many different primates, but expression of this capacity can depend upon environmental pressure and opportunity. Observations of chimps and orangutans indicate that aggressive behavior (“warfare,” in some chimp cases) may increase when territorial encroachment occurs.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Human-Primate Differences –Sharing, Cooperation, and Division of Labor Sharing and cooperation are common to most primates; however, humans do it much more complexly. Human foraging bands tend to have a sexual division of labor, other primates do not. Homo sapiens is the only primate species that engages in food sharing consistently on a large scale. –Mating and Kinship Human females do not experience estrus. Marriage and kinship are found in all human social systems but are absent from other primate societies.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Chronology –The history of vertebrate life on earth is divided into three eras: Paleozoic; Mesozoic; and Cenozoic. Each era is divided into periods and each period is divided into epochs. –Anthropologists are concerned with the two periods of the Cenozoic era: the Tertiary and Quaternary. The Tertiary period has five epochs: Paleocene; Eocene; Oligocene; Miocene; and Pliocene. The Quaternary period has two epochs: Pleistocene and Holocene.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Early Primates –Arboreal theory Primates became primates by adapting to life in trees. Enhanced sight (depth perception) Grasping hands and feet –Visual predation hypothesis Binocular vision, grasping hands and feet, and reduced claws developed because they facilitated the capture of insects. Early primates first adapted to life in the bushy forest undergrowth and low tree branches.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Early Cenozoic Primates The earliest primates date to the first part of the Cenozoic (65-54 m.y.a.). The Eocene (54-38 m.y.a.) was the epoch of prosimians with at least 60 different genera in two families. Anthropoids branched off from the prosimians during the Eocene.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Oligocene Anthropoids During the Oligocene (38-23 m.y.a.), anthropoids were the most numerous primates. The parapithecid family may be ancestral to the New World monkeys. The propliopithecid family may be ancestral to Old World monkeys, apes, and humans.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates Miocene Hominoids –The earliest hominoid fossils date to the Miocene epoch (23-5 m.y.a.). –Proconsul Proconsul was the most abundant anthropoid in the early Miocene. Its teeth have similarities with modern apes, but below the neck the skeleton is more monkey-like. Their teeth suggest that they ate fruits and leaves. Proconsul probably contained the last common ancestor shared by Old World monkeys and the apes.

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –Later Miocene Apes More than 20 species of primates have been discovered that date to the Late Miocene. Middle and Late Miocene apes are often grouped into two families: Ramapithedidae and Dryopithecidae. There are at least two ramapithecid genera: Sivapithecus and Gigantopithecus

McGraw-Hill © The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 4 The Primates –The Late Miocene Human ancestors almost certainly diverged from those of chimps and gorillas in the Late Miocene around 13 m.y.a. Toumai is the name given to the 6 to 7 million year old primate skull found in northern Chad. –It may be the oldest human ancestor found yet. –The skull belonged to an adult male with a chimp- sized brain ( cm3), heavy brow ridges, and a relatively flat, human-like face. –The find blends human and apelike features. –The find suggests that human ancestry was not confined to eastern and southern Africa.