Unit 2Primate Anatomy and Behavior, Dating Methods, Fossil Formation, Primate Evolution, and Introduction to PaleoanthropologyTaxonomy•Primate types: prosimians, New World monkeys (NWMs), Old World monkeys (OWMs), and apes •Anatomic vs. genetic similarities → in transition → proposed changes •Name change in primate suborders •Traditional: Prosimii (lemurs, lorises, and tarsiers) / Anthropoidea (monkeys, apes, and humans) •Proposed: Strepsirrhini (lemurs and lorises) / Haplorrhini (tarsiers, monkeys, apes, and humans) •Reclassification of the great apes (i.e., family names) •Traditional: Pongidae (great apes) / Hominidae (humans) •Proposed: All Hominidae (great apes and humans)Studies•1920s–1930s: descriptive studies •1950s–1960s: observational studies (e.g., Jane Goodall among chimps and Dian Fossey among mountain gorillas) •1970s–present: theoretical paradigms for research grants •Behavioral ecology: the study of the relationship between the environment and behavior •Sociobiology: the study of the relationship between genetics and behaviorCharacteristics•Limbs and locomotion •Erect posture •Hands and feet •Independent movement of five digits •Opposable thumb and big toe •Prehensile: the ability to grasp and manipulate •Flexible limb structure •Quadrupedalism: movement using all limbs simultaneously (e.g., knuckle walking or slow climbing) •Leaping/jumping •Brachiation: arm-swinging, suspended by the limbs, alternating weight-bearing on the limbs •Semibrachiation: the use of the tail as well as the forelimbs in brachiation •Bipedalism: movement on two limbs (e.g., humans as obligate bipeds)•Senses and brain •↑ reliance on vision •↓ reliance on smell •Enhanced touch in fingertips and toes •Encephalized: brain size > body size •Maturation, learning, and behavior •K-selected have a fewer number of offspring at one time, born immature and unable to care for themselves, require a lot of parental investment, have slow maturation rate, and tend to have long lifespans and pregnancies. Many mammals are K-selected. •r-selected species have many offspring at one time, the offspring are born mature and require very little if any parental care, and tend to have short lifespans and pregnancies. Many non-mammals are r-selected. •Arboreal (i.e., live in trees) vs. terrestrial (i.e., live on the ground) •Diurnal (i.e., active during the day) vs. nocturnal (i.e., active during the night) •Flexible, learned behavior: capable of learning in a wide variety of environments; passive learning curve •Social: Primates like to have company. Exceptions are considered solitary. •Arboreal hypothesis: the idea that the suite of characteristics that differentiate primates from other mammals evolved as a result of adapting to life in an arboreal environmentDental Characteristics•Heterodont: different types of teeth •Incisors: front, blade-like teeth for biting food •Canines: big, sharp teeth for tearing food •Premolars: side teeth for grinding food •Molars: side teeth for grinding food •Diastema: a space between teeth•Dental formula: a standardized way of describing dentition reflected in ½ of the mouth •Maxilla: the upper jaw •Mandible: the lower jaw •NWMs and OWMs differ in the number of premolars.NWMsOWMs, Apes, and HumansMaxilla2.1.3.3.2.1.2.3.Mandible2.1.3.3.2.1.2.3.Diets•Forager: an organism that searches for food daily •Omnivore: an organism that eats many foods •Frugivore: an organism that eats mainly fruits •Insectivore: an organism that eats mainly insects •Folivore: an organism that eats mainly leaves •Carnivore: an organism that eats mainly meatsSexual Dimorphism•Differences between the sexes in size, shape, or coloration (e.g., bright peacocks vs. drab peahens) •High degree in gorillas, moderate degree in humans, and low degree in chimpsSocial Structure•Residence pattern: the size of a primate’s social group (e.g., the number of males to females or adults to offspring) •Solitary: Once individuals reach adulthood, they live alone. Females have dependent offspring with them, while males generally don’t participate in raising offspring. •Pair-bonded: A male and female form a bond that generally lasts throughout their lifetime. They and their offspring form their core unit. This isn’t as rare as solitary but is rare in nonhuman primates. •Polyandry: There’s a single, mature, and ovulating female and multiple adult males in the group. As long as females remain within the group, they won’t reach sexual maturity. This too is rare. •Polygyny: There’s a single adult male and multiple females in the group. The adult male leads the direction the group moves, and other males are chronological subadults. When juvenile males sexually mature, they leave the group. This is common in nonhuman primates especially gorillas. •Multimale-multifemale: There are multiple males and multiple ovulating females in the group of variable size. They split into subgroups then return together at different times. This is common. •All male: This coexists in species that have other social structures (e.g., polygynist and slightly in multimale-multifemale).Geographic Distribution•Found in forested regions and warm climates •Different from where their fossils were foundProsimians•Least specialized primate with characteristics more similar to mammals than primates •Rely to a large extent on smell than sight; long snout •Postorbital bar: the lateral border of the eye orbit •Short gestation and maturation •Dental comb: a dental specialization of the mandibular incisors that projects anteriorly and superiorly for grooming and eating •Grooming claw: a specialized digit on the forelimb that’s elongated and thin more for eating than grooming•Lemurs!•Indigenous to and ⅓ extinct in Madagascar •Diverse in size and behavioral adaptations •Examples: small mouse lemur and large sifaka •Lorises!•Tiny bodied and nocturnal while most primates aren’t •Rely to a large extent on olfaction and vocalization •Recognize each other, mark territories, and predatory defense •Examples: bush baby and slow loris •Tarsiers!•Considered to be prosimians but genetically similar to anthropoids •Tiny bodied and found in the South Pacific •Climbers as quadrupeds and leapers; large muscles in hind