Exam #2 Study Guide Geological Time ScaleEras: a major division of time that is a subdivision of an eon and is itself subdivided into periodPeriods: one of several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These periods form elements of a hierarchy of divisions into which geologists have split the earth's history.Epochs: a division of time that is a subdivision of a period and is itself subdivided into ages, corresponding to a series in chronostratigraphyPaleozoic Era (aquatic forms): It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to youngest): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon, and is followed by the Mesozoic Era.Mesozoic Era (dinosaurs): an interval of geological time from about 252 to 66 million years ago. It is also called the age of reptilesCenozoic Era (mammals): The most recent era of geologic time, from about 65 million years ago to the present. The Cenozoic Era is characterized by the formation of modern continents and the diversification of mammals and plants. Grasses also evolved during the Cenozoic.Modern Era: Modern history can be further broken down into the early modern period and the latemodern period after the French Revolution and the Industrial Revolution. Contemporary history is the span of historic events that are immediately relevant to the present time. Themodern era began approximately in the 16th century.Pangea: Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It formed approximately 300 million years ago and then began to break apart after about 100 million years.Continental Drift: the movement of continents on sliding plates of the earth’s surface. As a result, the positions of large landmasses have shifted drastically during the earth’s historyTaxonomyCladistic taxonomy: An approach to classification that attempts to make rigorous evolutionary interpretations based solely on analysis of certain types of homologous characters (those considered to be derived characters)Homologies: similarities between organisms based on descent from a common ancestorAnalogies: similarities between organisms based strictly on common function, with no assumed common evolutionary descentSpecies: a group of organisms that can interbreed to produce fertile offspring. Members of one species are reproductively isolated from members of all other species (they cannot mate with them to produce fertile offspring)Genus: a group of closely related speciesANT 102 1st EditionMammalian Evolution: we learn about mammalian evolution through fossils and from studying DNA of living speciesAdaptive radiation: the relatively rapid expansion and diversification of life-forms into new ecological nichesMonotremes: are extremely primitive, egg-laying mammals. One example is the platypus Marsupials: Infants complete development in pouchPlacental mammals: during the Cenozoic, placentals became the most widespread and numerous mammals and today are represented by upward of 20 orders, including the primatesPrimitive CharacteristicsDerived Characteristics: characteristics that are modified from the ancestral condition and thus diagnostic of particular evolutionary lineages Homodont: having teeth that are all the same typeHeterodont: having different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molarsBinocular vision: vision characterized by overlapping visual fields provided by forward-facing eyes. Binocular vision is essential to depth perceptionPrimatesStrepsirrhines:the primate suborder that includes lemurs and lorisesHaplorrhines: the primate suborder that includes tarsiers, monkeys, apes, and humanProsimians and CharacteristicsLemurs and Lorises: Most primitive of primates, Strepsirrhine, Similarities to non-primates mammals: rhinarium (emphasis on olfaction), more laterally placed eyes (less visual acuity), large olfactory lobe in brain- smell, shorter gestation and maturation. Derived characteristics: dental comb, grooming claw, dental combTarsiers: Haplorrhine primates, no tooth comb, nocturnal, insectivores, stable pair bondsAnthropoids: members of the primate infraorder Anthropoidea, which includes monkeys, apes, and humansNew World Monkeys: Southern Mexico, central and south America, almost exclusively arboreal, Platyrrhini (flat nosed), Callitrichidae family (marmosets and tamarins), Cabidae family (squirrel, capuchin), prehensile tail: spider, howler monkeys. Marmosets and tamarins: Most primitive, retain claws, no nail, twins, insectivorous, quadrupedal locomotion, some clinging and leaping, Small family groups-mated pair and offspring, Males heavily involved in infant care. Other new world monkeys: Eg squirrel monkey, capuchin: Fruit, leaves, supplement with insects ,quadrupedal, Spider monkey-semibrachiator, some with prehensile tail, locomotion and suspend while feeding, groups with both sexes, or monogamous pairs with offspringOld World Monkeys: Tropical forests, semiarid desert, and snow covered areas in Japan and China. Characteristics: baboons are terrestrial quadrupedal, macaques are arboreal quadrupedal, colobus monkey are semi-brachiatrion, acrobatic leaping. Social organization- Colobines- small groups, only 1 or 2 adult males, Baboon and many macaques- large social units, several adults both sexes, offspring all ages, Monogamous pairing rare in old world monkeys (vs new world more common)Prehensile tails: purposes include locomotion and suspension while feedingLocomotion: movement or the ability to move from one place to another -Quadrupedal: using all four limbs to support the body during locomotion; the basic mammalian (and primate) form of locomotion -Brachiating: arm-swinging, a form of locomotion used by some primates. Brachiation involves hanging from a branch and moving by alternately swinging from one arm to the otherArboreal Hypothesis: The arboreal hypothesis is a hypothesis that explains primate origins. It states that primates' unique set of traits is an adaptation to living in trees.Visual Predation Hypothesis: suggests that primates evolved as a result of the pressure to forage fruits and insects nocturnallyHominoids (social behavior, basic social group, locomotion, diet): members of the primate superfamily that