Tuesday, August 23, 2011
9/27/11 9:46 AM
Monogamy: one man, one woman Polygyny: one man, two or more wives Polyandry: one woman two or more husbands Anthropology: the study of the biological and cultural evolution and diversity of human beings, past and present. Is a comparative discipline, which seeks to understand what makes people different and what they all have in common. Anthropologists: concerned with the description and explanation of reality Formulate and test hypotheses concerning humankind so they can develop theories about our species. Principle of anthropology: various parts of culture must be viewed in the broadest possible context in order to understand their interconnections and interdependence. Theories about the world and reality based on the assumptions and values of ones own culture. 4 sub fields of anthropology Physical anthropology (biological anthropology): Focuses on humans as biological organisms, evolution, and human variation. Analyze fossils and observe living primates to reconstruct the ancestry of the human species. The biocultural perspective focuses on the interaction of biology and culture. Paleoanthropology (the study of the origins of the human species.) Forensic anthropology (specializes in the identification of human skeletal remains for legal purposes.) Primatology ( the study of living and fossil primates.) Human growth, adaptation, and diversity ( the study of the ways in which
the natural and cultural environment impacts human growth and biological diversity.)
Archaeology: studies material remains in order to describe and explain human behavior. Study tools, pottery, and other features such as hearths and enclosures that remain as the testimony of earlier cultures. Bioarchaeology, the study of human remains as a record of cultural processes. Cultural resource management, tied to government policies for the protection of cultural resources and involving surveying and/or excavating archaeological and historical remains threatened by construction or development. CRM is about stewardship of cultural resources. Linguistic anthropology: description of a language the way a sentence is formed or a verb conjugated. History of languages, the way languages change over time. The study of language in its social setting, such as discourse. Cultural anthropology: The study of different patterns in human behavior, thought, and feelings. Focuses on humans as culture-producing and culturereproducing creatures. Culture: A societies shared and learned ideas, values, and perceptions, which are used to make sense of experience and which generate behavior and are reflected in that behavior.
Applied anthropology (uses knowledge and methods from the four sub fields to solve practical problems, often for a specific client.) Anthropology is empirical based on observation of the world rather than on intuition or faith. Anthropology uses theory (an explanation of natural phenomena, supported by a reliable body of data Anthropology uses hypothesis (tentative explanation of the relation between certain phenomena.)
Ethics of Anthropologists: Obligations to whom we study, those who fund the research, those in the profession who expect a study to be published so they can further the research in the field Globalization refers to worldwide interconnectedness, evidenced in global movements of natural resources, human labor, finance capital, information, infectious diseases, and trade goods. Technology is the driving force in globalization. Innovations, lower transportation and communication costs, faster knowledge transfers, and increased trade and financial integration among countries.
Thursday, August 25, 2011
Introduction to Genetics and Evolution
Linnaean Classification: a classification system that grouped lving thing into groups based on similarity of form, function, and growth Placed humans among the prmates(apes, monkeys and prosimians) and mammals (having hair or fur and suckle their young). Binomial Nomenclature which organized living things into species and genera. Taxonomy uses body structure, body function and patterns of growth but also examines genetic material and protein structures to make classifications Modern taxonomy uses Cladistics Cladistics compares animals based on:
-analogies (anatomical features with similar functions) -homologies (anatomical features evolved from a common ancestral form) *Bat wing and human hand are homologies Jean-Baptiste Lamarck was among the first to suggest an evolutionary mechanism. His theory of the inheritance of acquired traits proposed that intentional behavior on the part of individuals brought about changes in the form of entire species. Sir Charles Lyell developed uniformitarianism. Argues that major features one earths surface through gradual accumulation of minute changes, brought about by the same natural processes, such as erosion, that are observable today. Lamarcks theory of evolution recognized that species did change ( was wrong about how) Lyell’s uniformatiarianism expanded the age of the earth (allowing more time for evolution to happen) Malthus observed that animals produce many offspring but not all of them live to maturity Darwins theory of evolution All species display a range of variation, and all have the ability to expand beyond their means of subsistence. In struggle for existence organism with variation that help them to survive in a particular environment will reproduce with greater success than those without them. As generation succeeds generation, nature selects the most advantageous variations and species evolve.
Darwin did not know the mechanism for transmission of traits.
Gregor Mendel and the Science of Heredity Experimented with plant pollination to establish the laws of heredity Mendel discovered that inheritance was particulate, rather than blending as Darwin thought Darwin had his 1866 paper bud did not read it Mendel’s work gave rise to science of genetics Mendel’s Law of Segregation During reproduction, the genes governing the expression of a trait will be separated and keep their individuality They will be passed on to the next generation, unaltered. This process is called meiosis Mendel’s Law of Independent Assortment During reproduction, each parent donates segregated genes In the offspring, these segregated genes recombine in a random manner and independently from one another Individual traits are inherited independently
Alleles- variants of a gene that occur in the same location on a chromosome or DNA molecule. We one allele from each parent. Sexual reproduction actually increases genetic diversity in a species. Meiosis – Sex cell production Following Mendel’s law of segregation, the alleles from the parent chromatid are separated Homozygous individuals with identical alleles, the sex cells have the same alleles Heterozygous individuals with different alleles, half the sex cells will one allele, the other half will have a different allele for the same trait.
Phenotype and Genotype Phenotype are the traits that are visible or observable. A person’s genotype or genetic composition can never be fully predicted because of the segregation and independent assortment of genes and alleles. In addition, during meiosis corresponding portions of one chromosome may cross over to the other one, somewhat scrambling the genetic material compared to the original chromosomes. Mendel’s law of dominance Not all of the genes/alleles present in an organism (genotype) will be expressed physically (phenotype).
Some genes/alleles are recessive and will not be expressed in the presence of dominant genes or alleles Dominant>recessive In some cases, genes/alleles may be co dominant with others and both will be expressed. Phenotype Genotype A AA, AO B BB, BO AB O AB OO
Punnett Squares is a method for measuring the probability of a certain genotype appearing based on the crossing of two organisms with known genotypes.
Polygenetic Traits Mendel’s laws work best for Mendelian traits- physical traits coded by one gene (with multiple alleles) Most human traits (like height and skin and eye color) are polygenetic and are coded on several genes Evolution, Population, and Individuals Evolution acts on individual traits but indiviuals don’t evolve, only population evolve Populations that can still produce fertile offspring are still considered part of the same species
Such populations have a distinctive gene pool or all of the genetic variation possessed by individuals in the population. Natural selection occurs at individual level. Population is where evolution occurs. Reproductive isolation – the populations will no longer be able to interbreed Forces of microevolution mutation genetic drift gene flow natural selection Mutation Random genetic change occurring during mitosis or meiosis Can be beneficial, harmful o not noticeable Mutagens or chemical in the environment can increase the chances of mutation Without the variation brought in through random mutation, populations cannot change over time in response to changing environments Genetic Drift Chance changes in the allele frequencies of a population due to accidents or other events Result in greater changes when populations are small or isolated = the founder effect Gene Flow
Changes in the allele frequencies of a population due to the infusion of genetic material through interbreeding with another population Among humans, social factors like mating rules, intergroup conflict and our ability to travel great distances can affect gene flow. Natural Selection Natural selection refers to the evolutionary process through which genetic variation at the population level is shaped to fit local environment conditions. Natural selection is not equal to survival of the fittest in the sense meant by Herbert Spencer. Best measured through reproductive success (mating and production of viable offspring) Eg. Peppered moth (light to dark) in London during industrial boom
Tuesday, August 30, 2011
Primatology Biologists classify humans as belonging to the primate order, a mammalian group that also includes lemurs, lorises, tarsiers, monkeys and apes. Primatology is the study of the biology behavior and evolutionary history of our closest living relatives, the non-human primates. Primatologists study the biology and behavior of living non-human primates both in their natural habitats and in captivity at zoos, primate research colonies, or learning laboratories.
Genus: Homo Species: Sapiens Subspecies: Sapiens Our place in nature: primates as mammals Like reptiles and birds, mammals have lungs. Mammals are warm-blooded like the birds Mammals have fur or hair Female mammals produce milk Mammals have large brain sizes compared to their bodies
Generalized set of teeth (heterodonty), suited to insect eating but also fruits and leaves (omnivory). Depth Perception Binocular stereoscopic vision with three-dimensional vision Intensified sense of touch (due to tactile pads on the digits) Opposable thumbs
Primate Characteristics Brain is large and heavy in proportion to body weight, and very complex.
Skeleton has adaptations for upright posture and flexibility of limb movement Few offspring born to each female and a longer period of infant dependency Most primates are diurnal although some prosimians may retain the original nocturnal adaptation of early primates. Primate Characteristics: Teeth Compared to some animals with identical teeth; primates are heterdonts – they have different teeth with specific dental formulae (arrangement of different kinds of teeth) Prosimians and Platyrrhines have a 2-1-3-3 dental formula Catarrhines (including humans) have a 2-1-2-3 dental formula
Primate Characteristics The primate braincase, or cranium, tends to be high and vaulted In humans, the vertebral column joins the skull toward the center of its base, less so for other primates In anthropoid primates, the snout or muzzle portion of the skull is reduced In each primate arm or leg, the upper portion of the limb has a single long bone, the lower portion two long bones, and then hands or feet have five radiating digits (pentadactyly)
Lemurs and Lorises Highly developed sense of smell for a primate (have a rhinarium)
Claw-like fingernails Tend to be quadrupedal (walk on four legs) and arboreal Have tails
Tarsiers Smallest of the primates Claw-like fingernails Tend to be arboreal Have tails The Monkeys Other than humans, the most widespread type of primate Larger than prosimians; they also have a tail Quadrupedal and can be either arboreal (live in the trees) or terrestrial (ground) New World Monkeys Found only in tropical rainforests but have adapted to all levels of the canopy Tend to form large multi-family social groups Platyrrhines
Some have prehensile tails
Old World Monkeys Found in a variety of environments- savanna, forest and snowy mountains Tend to form large multi-family social groups Non-prehensile tail Catarrhines (like apes and humans) The Hominoids: apes Largest of the primates in overall body size and brain size No visible tail Quadrupedal, knuckle walking, and brachiation (jump and swing from tree limb to limb) Have the most restricted habitats – tropical central Africa and Southeast Asia Great apes and lesser apes The Great Apes Largest of the apes Tend to form large and complex groups Includes chimpanzees, bonobos, gorillas, and orangutans Primarily terrestrial but some are arboreal
The Lesser Apes Smallest of the apes End to form large and complex groups Includes gibbons and siamangs Primarily arboreal
Humans as Primates Similarities: opposable thumbs and prehensile hands, diurnal (active during the day), stereoscopic and color vision, like old world monkeys and other hominoids we are catarrhines, like apes we lack visible tails and have large bodies/brains Differences: fully terrestrial (only arboreal for certain activities), bipedal, unlimited range
Threats to Primate survival and conservation efforts All great apes are listed as endangered species Economic development (farming, lumbering, cattle ranching, tuber tapping), as well as by hunters and trappers who pursue them for food, trophies, research, or as exotic pets Another threat to great apes comes from disease. There are over nineteen viruses and eighteen parasites that are known o infect both great apes and humans.
Traditional conservation efforts emphasized habitat preservation above all else. In direct conservation efforts, primatologists work to maintain some populations in the wild, either by establishing preserves where animals are already living or by moving populations to places where suitable habitat exists.
Primate Behavior Apes in the wild: difficult to gain confidence of the primates, better able to judge behavior without human interference Apes in captivity: convenient and easy to study, behavior may be altered
Primates as models for human evolution Because we cannot observe the way in which our ancestors behaved and apes are our closest living relatives, paleoanthropologists have been hopeful that observation made among the living apes might shed light on the lifeways of our ancient pre human ancestors. This perspective is known as the primate analogy Three species of primates are favoured among anthropologists as models for how ancestor may have behaved: baboons, chimpanzees, bonobos
The Primate Analogy: Baboons Advantages: live in same environment as our ancestors – the eastern and southern African savanna, aggression and male dominance in society were
once seen as the norm in human evolution( ex: the man the hunter hypothesis) Problems: baboons are not hominoids (and we do not posses ischial callosities), humans are less sexually dimorphic and human societies are not always organized around a dominance hierarchy The Primate Analogy: chimpanzees Advantages: chimps and humans share 98.5% of their genetic material, capacity for cultural behavior – language, tool-making, like baboons, chimps appear to have an aggressive streak we assume was part of human evolution (ex: the man the hunter hypothesis) Problems: humans are not bound o the estrus cycle, chimpanzees have undergone highly specialized adaptations – e.g. knuckle- walking The Primate Analogy: Bonobos Advantages: like chimps, bonobos and humans share 98.5% of their genetic material, capacity for cultural behavior – language, tool-making, bonobos are not bound to an estrus cycle for copulation Problems: we are not yet sure how bonobos, chimps and humans are related in evolutionary terms Primate Social Organization Although all primate societies are characterized by a dominance hierarchy, each species (and sometimes groups within a species) has preferred forms of social organization All primate societies are organized around dominance hierarchies – a social order of dominance sustained by aggressive or other behavior patterns
This form of social organization is often linked to sexual dimorphism – differences of sixe and anatomy between males and females of a species
Lowland Gorilla Societies Lowland gorillas favor age-graded groups consisting of a dominant male (silverback), younger males, adult females, and children Sometimes identified as harems, only the silverback male mates with the adult females There can be competition for the dominant male position within a group Chimpanzee and bonobo societies Chimpanzees favor multi-male/multi-female groups with some age grading Bonobos favor polyamorous unions within multi-male/multi-female groups Savanna baboon societies Like lowland gorillas, baboons favor age-graded groups (sometimes identified as harems)
Siamang and gibbon societies Tend to form monogamous pairings Individual interaction and bonding All primate societies have ways of settling disputes –social control. For example, grooming (tasty snacks and hygiene), aggressive displays (not always violence), genital manipulation (among bonobos only)
Chimpanzees and bonobos supplement this diet by the deliberate and organized group hunting of other primates like the colobus monkey Most primates are omnivores Sexual behavior All primate females signal ovulation through an estrus cycle (usually accompanied by seasonal genital swellings) Both males and females may initieate courtship: females may purse their lips and slowly approach a male females may try to establish prolonged eye contact females may be coerced o mate with multiple males during the estrus period males may approach a female and make a display males may also touch females and give a train grunt Sexual behavior of chimpanzees For chimps, sexual activity occurs only when females signal their fertility through genital swelling. Dominant males try to monopolize females, although cooperation from the female is usually required for this to succeed. A female and a lower – ranking male sometime form a temporary bond leaving the group together for a few private days during the female’s fertile period.
Sexual behavior of bonobos Bonobos do not limit their sexual behavior to times of female estrus, bonobo female genitals are perpetually swollen.
Like human females, concealed ovulation in bonobos may play a role in the separation of sexual activity for social reasons and pleasure from the biological task of reproduction Primatologists have observed every possible combination of ages and sexes engaging in an array of sexual activities (oral sex, tongue kissing, and massaging each others genitals). Reproduction and care for the young Reproduction among primates follows a k-selection strategy This reproductive strategy means that the mother infant social bond is very important in primate societies, especially among hominoids (apes and humans) However, this bond can be replaced by other social bonds Father-infant bond Allomothering
Play and learning Young chimpanzees and bonobos learn by observation, imitation, and practice how to interact with others and manipulate them for his or her own benefit Young primates learn to match their interactive behaviors according to each individuals social position and temperament.
Anatomical features such as a free upper lip allow varied facial expression, contributing to grater communication among individuals Young chimpanzees and bonobos also learn how to make and use tools
Tool-making The great apes and some catarrhine monkeys are also able to make tools Their ability to not only invent tools but to share the skill with others makes tool-making cultural behavior in the sense that its learned and shared behavior attached to a specific social group (not the whole species) Japanese macaques and rice in sand example Chimpanzees are famous for modifying natural objects to make tools (the very definition of the word “tool”) Orangutans have also been observed to make tools in the same manner as chimpanzees (i.e. by modifying natural objects) Bonobos have been observed making stone tools using a flake-knapping technique similar in many ways to the stone tool technologies of our ancestors Primate communication What defines human language? symbolic syntax not dependent on a direct stimulus human languages can be modified (new words are added, old ones removed, syntax can be changed) Early views of primate communication:
Only antamoically modern humans were capable of language 9as a verbal symbolic system) Apes and our non or pre-human ancestors could communicate but not like us We now know that: captive apes can be taught to use symbols for communication, apes who use symbolic communication follow syntax and can modify their language by creating new words , apes in the wild do not use syntax or symbols and their communication is stimulus-dependent
Tuesday, September 6, 2011
Archaeological Field Methods Prehistory and History The term prehistory is used to refer to the period of time before the appearance of written records. This does not deny the existence of history, merely of written history. Paleoanthropology is the study of the physical remains of our ancestors and other ancient primates. Paleoanthropologists do more than find and catalogue old bones. Paleoanthropologists recover, describe and organize these remains to see what they can tell us about human biological and cultural evolution. Recovering cultural and biological remains
The only way to thoroughly investigate our past is to excavate (dig) sites where biological and cultural remains are found. The fundamental premise of excavation is that all digging is destructive, even that done by experts. The archaeologists primary responsibility, therefore, is to record a site for posterity as it is dug because there are no second chances. (Brian Fagan, archaeologist) Material culture-stone tools, pottery, skeletal remains, contexts Types of material culture The term material culture refers to the durable aspects of culture such as tools structures, and art. Artifacts – objects that have been modified by hominids (stone tools, ceramics and wood tools) Manuports – natural objects that were carried by hominids but not modified Ecofacts – natural objects found in association with hominids (plant remains, animal remains) Features – large, non-portable modified objects found at hominid sites ( hearths, buildings, large statues, rock, art etc.) Nazca lines are a feature Nature of Fossils The term fossil refers to any mineralized trace or impression of an organism that has been preserved in earth’s crust from past geological time. It is also important to understand the kinds of factors that led to the placement of the fossil within the ground as well as affected its preservation
Taphonomy – the study of what happens to bones and other material remains once they have been discarded or the animal has died, and before they are excavated. Taphonomy Cultural transforms – burial, mortuary ritual, plowing, looting Natural transforms – erosion, weathering, scavenging, natural disasters, animal action in the soil, climatic conditions Natural and cultural burial of the dead Entirely preserved fossil skeletons dating before the cultural practice of burial about 100,00 years ago are quite rare. The human fossil recorded from before this period consists primarily of fragmentary remains The fossil record for many fossil primates is even poorer because organic materials decay rapidly in the tropical forests where they lived. By contrast, the fossils of our pre-human ancestors are generally better preserved because of the arid savanna in which they were located.
Artifacts and fossils Places containing archaeological remains of pervious human activity are known as sites There are many kinds of sties and sometime it is difficult to define their boundaries for remains may be strewn over large areas. Sites are even found underwater.
Site identification The first task for the archaeologist is actually finding sites to investigate Usually archaeologists survey a region in order to plot the sites available for excavation. A survey can be made from the ground, but more territory can be covered using aerial photography. Innovations such as geographi information systems, remote sensing, and ground penetrating radar often complement these exploration methods What archaeologists look for: Soil marks or stains that show up on the surface of recently plowed fields. These may reveal an archaeological site. Middens or refuse or garbage disposal areas in an archaeological site. May appear to be large mounds. Excavation Since excavations are destructive, archaeologists must carefully record the location of material remains in three-dimension space To begin, the land is cleared, and the places to be excavated are plotted as a grid system – a system for recording data in three dimensions from an archaeological excavation. Usually divides a site into squares ( 1m x 1m) Grids are established using a datum point or reference point for a grid system Trowels are used to scrape the soil, and screens are used to sift all the loose soils so that even the smallest artifacts, such as flint chips or beads are recovered.
Some archaeologists use flotation – a technique used to recover very tiny objects by immersion of soil samples in water to separate heavy from light particles.
Example of stratigraphy If a site is stratified (contains layers of cultural and biological remains), each layer or strata is excavated separately. State of preservation Artifacts made of inorganic materials such as stones are preserved better than artifacts made of perishable materials (unless there are favorable climatic conditions). Sometimes the impressions of organic objects (such as post holes) can provide clues about the objects themselves Sorting out the evidence Excavation records include a scale map of all the features, the stratification of each excavated square, a description of the exact location and depth of every artifact or bone unearthed, and photographs and scale drawings of the objects. In the lab, artifacts that have been recovered from an excavation must be cleaned and catalogued before they are ready for analysis. From the shapes of the artifacts as well as from the traces of manufacture and wear, archaeologists can usually determine their function Other kinds of information gathered from fossils:
Endocasts – cast of the inside of a skull which can help determine the size and shape of the brain Coprolites – preserved fecal material providing evidence of the diet and health of past organisms. Bioarchaeology and forensics The term bioarchaeology refers to the study of human remains emphasizing the preservation of cultural and social processes in the skeleton. Human Osteology Determines the sex, age (at death), and ancestral population of a skeleton from morphological features Determine wear patterns on the bones and teeth from repeated activities Comparison with other skeletons to determine species affiliation Paleopathology: bone information Iron deficiency causes anemia – porous bones Vitamin d deficiency causes legs to grow bent Malnutrition or under-nutrition is inferred from skeletal measurements Infections Various cancers Paleopahtology Trauma in skeletons is clearly evident in bone fractures, especially when they have not healed successfully
The individual workload leaves traces in the skeleton Growth disrupting and growth-retarding stresses during childhood will leave transverse lines of dense bone visible in radiograph of long bones of the body. Dating the past Two types: Relative dating – designating an even, object, or fossil as being older or younger than another. Absolute or chronometric dating – provides dates for recovered material based on solar years, centuries or other units of absolute time. Relative dating techniques Stratigraphy – a technique for relative dating based on organizing remains by means of strata. Objects in lower strata are older than objects in higher strata Seriation – a technique for relative dating by putting groups of objects into a sequence in relation to one another Palynology – a method of relative dating based on changes in fossil pollen over time
Absolute dating techniques Radiocarbon dating – a technique of dating based on measuring the amount of radioactive carbon (14c) left in organic materials found in archaeological sites.
Dendrochronology – a method of dating based on the number of rings of growth found in a tree trunk. Potassium-argon dating: a method of absolute dating based on measuring the amount of radioactive potassium left in a layer of volcanic rock
Chance and the study of the past The archaeological and fossil records are imperfect, partial, and nonrepresentative Chance circumstances of preservation and discovery have determined what has survived the ravages of time to be excavated by archaeologists.
Thursday, September 8, 2011
Macroevolution and the process of speciation Macroevolution – evolution above the species level (creation of new species i.e. lizards color in California) Speciation – the process of forming new species Since species are population who are capable of interbreeding and producing viable and fertile offspring (donkey and horse = mule) To create new species, population must separate through reproductive isolating mechanisms – biological and behavioral factors that separate breeding populations and prevent gene flow. Cladogenesis – speciation occurs when descendants of an ancestral population become reproductively isolated (divergent evolution)
Anagenesis – speciation through the gradual accumulation of advantageous traits Convergent evolution – flacon, bat, pteradactyl different ancestors, but all can fly Parallel evolution – ancestral population are more closely related (placentals and marsupials) Time of evolution Gradual evolution – suggested by Charles Darwin, physical traits change slowly and consistently over time Punctuated equilibria – suggested by Stephen Gould, evolution occurs via long period of stability or stasis punctuated by periods of rapid change Genetics and evolution Change in the timing of growth and development – Heterochrony - can be responsible for changes in the shape or size of a body part. The differences between chimpanzees and humans are sometime linked to a type of heterochrony known as neotony (the retention juvenile traits). Evolutionary relationships Evolutionary relationships can be traced through: homologous traits – originate from a common ancestor (human arm & seal flipper) analogous traits – reflect similar environmental pressures not ancestry (bee wing & bird wing) constructing evolutionary relationships
In addition to homologous and analogous traits, evolutionary relationships can be traced : derived traits – traits found in a group of organisms that did not exist in ancestral populations ancestral traits – traits possessed by an organism or group of organisms due to shared ancestry Examples. Bilateral symmetry Macroevolution of the early primates Continental drift – according to the theory of plate tectonics, the movement of continents embedded in underlying plates on the earths surface in relation to one another over the history of life on earth. Such changes can also affect the climate and environment. Early mammals Mammals appear as early as 190 million years ago Around 70 mya, the earth began to experience sever climatic changes and many of the larger reptiles and dinosaurs went extinct, opening new environmental niches for mammals. Mammal-like animals were preadapted to advantages of these changes and underwent an adaptive radiation – a rapid increase in the number of related species following a change in their environment. Early mammals: adaptive traits Mammals are homoetherms – animals that maintain a relatively constant body temperature despite environment fluctuations. By contrast, reptiles are isotherms – animals whose body temperatures rise or fall according to the temperature of the surrounding environment.
Mammals are k-selected – reproduction involves the production of relatively few offspring with high parental investment in each Other animals are more r-selected – reproduction involves the production of large numbers of offspring with relatively low parental investment in each. The proto-primates (65 mya) The first primate-like mammals, or proto-primates, were roughly similar to squirrels and tree shrews in size and appearance The existing, very fragmentary fossil evidence (mostly from north Africa) suggests that they were adapted to an arboreal way of life in warm, moist climates.
The rise of the primates The rise of primates appears to be an adaptive radiation linked to the spread of flowering plants (angiosperm radiation) and pollinating insects Arboreal hypothesis – a hypothesis for primate evolution that proposes that life in the trees was responsible for enhance visual acuity and manual dexterity in primates.
Visual predation – a hypothesis for primate evolution that proposes that hunting behavior in tree dwelling primates was responsible for their enhanced visual acuity and manual dexterity True primates – early prosimians Early prosimians had postorbital bars and relatively long snouts Their ones have been found in 55 million year old geological deposits in north America-Europe - Asia (laurasia) and Africa They were somewhat squirrel-like in sight and appearance, but apparently they had Early strepsirhines Fossils of lemur and loris ancestors are found in north America, Europe, asia Early haplorhines Fossials of haplorhines are found in north America, Europe, asia, an dpossible Africa. Main features: large eye sockets, shortened snouts, cheek teeth adapted for insectivourous or grugivourous Oligocene anthropoids By the Oligocene period, prosimians are out competed by anthropoids Platyrrhines (2-1-3-3) Catarrhine (2-1-2-3)
Aegoyptopithecus Oligocene anthropoid that had a combination of monkey and ape features The size of a large domestic cat (13-20lbs) Fruit and seed eating forest tree-dweller Had fewer teeth, less long snout, larger brains, and increasingly more forward-looking eyes than the prosimians The origin of new world monkeys The earliest platyrrhine fossils are found in south America and are only about 25 million years old Both playtrrhines and catarhines originated from porsimian ancestors Miocene ape) proconsul Existed from 27 to 17 million years ago in Africa Ranged in size from 22-84lbs Its monkey-like features included: thin tooth enamel, a light build with a narrow chest and short forelimbs and an arboreal quadrupedal lifestyle Its ape like features are its lack of a tail, ape like elbows, and a slightly larger brain relative to body size Dryopithecus
Existed from 12-9 million years ago in eastern Africa and Eurasia Had a y-5 cusp arrangement on its molar teeth typical of hominoids Sivapithecus Existed from 12.5-8.5 million years ago in india and Pakistan Possible ancestor of the orangutan and gigantopithecus already had separated from the common ancestor of chimpanzees and gorillas
Gigantopithecus Existed from 1 million to 300,00 years ago in china, india and Vietnam It stood about 10 feet tall and weighed as much as 1200 pounds Gigantopithecus was probably a quadruped and an herbivore , existing on a diet primarily of bamboo, possibly supplemented with seasonal fruits
Tuesday, September 13, 2011
Todd 276 Thursday 3:30 Anatomy of bipedalism Hominid = bipedal Recognize the bipedalism is the first human-like trait to evolve among apes Anatomy of Bipedalism Bipedalism can be inferred from the position of the foramen magnum, the large opening at the base of the skull
Note its relatively forward position on human skull compared to the chimp skull Anatomy of bipedalism: basin shaped pelvis Pelvic structure supports body weight Upper hipbones and lower limbs Compare the upper hipbones and lower limbs of homo sapiens, Australopithecus, and an ape Angle of the lower limbs from the hip joint to knees The similarities of the human and australopithecine bones are indicative of bipedal locomotion
The australopithecines Dated to 3.5-2.6 million years ago Found in Tanzania and Ethiopia (East Africa) Males (5ft tall) appear to have been much larger than those of females (3.54ft tall) Evidence of sexual dimorphism = males have larger canines Australopithecus afarensis
Postcranial anatomy and the laetoli footprints indicate striding bipedalism Ape like features had curved fingers Lucy: Australopithecus afarensis 40% complete skeleton of lucy, indicates that australopithecine ancestors were bipedal this adult female was only 3.5 feet tall paleoanthropologist recons trunk skeletons in its pelvis, the austrlopithecine resembles the modern human, but its rib cage shows the pyramidal configuration of the ape Upper Jaws Upper jaws of an ape, Australopithecus, and modern human show differences In the shape of the dental arch and the spacing between the canines and adjoining teeth. Australopithecine fossil locations Have been found in south Africa, Malawi, Tanzania, Kenya, Ethiopia and chad Two primary Australopithecus: Gracile australopithecines more lightly built chewing apparatus. No crest, face lower on skull, smaller zygomatic arch, front and back teeth of similar sizes
Robust australopithecines lived from 2.5 to 1.1 million years ago in eastern and southern Africa. Known for the rugged nature of their chewing apparatus (large back teeth, large chewing muscles, and a bony ridge on their skull tops for the insertion of these large muscles). Sagittal crest in the males, face higher on skull, wide flaring zygomatic arch, unbalanced dentition with very large molar teeth Later australopithecines and early homo The gracile and robust form of austrlopithecus appear to have developed in response to deforestation and the progressive drying of the environment These forms were ideally suited for plant foraging Predators posed a major problem and the yielding sticks, stones and bones as defensive weapons may have pave the way for stone tool making among early homo When two closely relatd species compete for the same niche, one will out compete the other, bringing about the alters extincition = law of competitive exclusion Early homo and later Australopithecus did not compete for the same niche and appear to have co- existed Genus homo: Homo Habilis 2.5-1.8 million years ago found in east and south Africa believed to have mastered the oldowan stone tool industry there is ample fossil evidence that H. habilis was a major staple in the diet of large predatory animals; so it was probably not a hunter
its brain size is slightly large than australopithecines, 500-600 cc its face is less prognathic than australopithecines bipedalism disadvantages makes an animal more visible to predators exposes the soft underbelly interferes with the ability to change direction instantly quadrupedal chimpanzees and baboon are 30-34% more faster than bipeds. Frequent lower back problems, hernias, hemorrhoids, and other circulatory problems Consequences of a serious leg or foot injury seriously hinders a biped and they are an easy meal for some carnivore Bipedalism advantages A way to cope with heat stress Allowed them to gather food and transport it to a place of safety for consumption Mothers were able to carry their infants safely They could reach food on trees too flimsy to climb Allowed them to travel far without tiring Reasons for bipedalism: the savanna model
Food and water were easier to spot – Savanna Model More likely to spot predators before they got too close for safety Hands freed from locomotion provided protection by allowing them to brandish and throw objects at attackers Hand freed from locomotion provided males the ability to carry more food to attract more mates
Thursday, September 15, 2011
Homo Habilis: “Handy Man” -the first fossil members of the genus Homo appearing 2.5 million years ago, with larger brains and smaller faces than australopithecines -found in east Africa and in south Africa -from the neck down the skeleton of homo habilis differs little from Australopithecus The Lower Paleolithic -the first part of the old stone age -its beginning is marked by the appearance 2.6 million years ago of Oldowan tools, the earliest identifiable stone tool tradition.
-the earliest stone tools have been found in the lake turkana area of Kenya, southern Ethiopia, olduvai gorge in Tanzania and the hadar region of Ethiopia most often found in the same geological strata as homo habilis fossils Oldowan tools -microscopic wear patterns show that these tools were used for cutting meat, reeds, sedges and grasses and for cutting and scraping wood -leftover core were transformed into choppers, for breaking open bones, and they may have been used to defend the user. The percussion method -2.5 million years ago homo in Africa had invented the percussion method of stone tool manufacture -increase in brain size, made possible the butchering of meat from scavenged carcasses Sex, gender and the behavior of early homo -until 1960’s, most anthropologists doing fieldwork among foragers stressed the role of male hunters and underreported female gatherers = man, the hunter hypothesis -division of labor by food foraging societies is not defined Hunters or gatherers? Earliest members of the genus homo were tertiary scavengers -they were third in line to get something from a carcass after a lion or leopard manged to kill -by the time H. habilis could get near the carcass of a dead animal, only bones remained -they used tools to break open the long bones to get at the rich marrow inside -the storing of stone tools, and raw materials for making tools, attest to their ability to plan ahead
Brain size and diet -the archaeological record provides a record of our ancestors cultural
abilities that corresponds with the simultaneous biological expansion of the brain. -meat eating most easily fulfills the energy requirements of brain expansion -meat eating also confers more leisure time to explore and manipulate their environment -200,00 years ago, hominid brain size had almost tripled homo erectus -2 million years to 300,000 years ago -larger cranial capacity than that of homo habilis; the forehead is less sloping and the teeth are smaller -homo erectus would bear a striking resemblance to modern humans, but had a brain about 75% of the size of modern human -the sexual dimorphism between males and females was almost the same as seen in modern homo sapiens with males being slightly larger physical traits of homo erectus -occipital or nuchal torus (projection at the back of the skull) -supraorbital torus (browridge) -postorbital constriction -lower facial prognathism -thick cranial bones -cranial capacity in homo erectus changed over time Homo erectus routes spread from Africa to Eurasia Why’d they migrate? curiosity lack of natural resources following migrating herds technologically capable of surviving the trek to the colder climates outside of Africa ended up as far west as china, as far south as southeast asia and into western Europe Homo floresiensis -identical to homo erectus
-Flores island, Indonesia -possible use of watercraft -dated to between 800,000-18,000 years ago Acheulean tool tradition -the tool making tradition homo erectus in Africa, Europe, and southwest asia in which hand axes were developed from the earlier oldowan chopper -hand axes 1.6 million years old -those found in Europe are no older than about 600,000 years ago Fire -use of fires is another sign o homo erectus developing culture and technology -700,000 year old kao poh nam rock shelter in Thailand provides compelling evidence for deliberate controlled use of fire -homo erectus may have been using fire even earlier, based on evidence from Swartkrans in south Africa Hunting -evidence that homo erectus developed the ability to organize in order to hunt large animals is suggested by remains such as those from 400,000 year old sites of ambrona and torralba, in spain 1995 in the course of strip mining at schoningen in northern Germany -five well constructed and finely balanced spears Language origins -regions of the human brain that control lingual lie adjacent to regions involved in precise hand control -oldowan toolmakers, like modern humans, were overwhelmingly right handed -handedness is associated with lateralization of brain function and lateralization is associated with language -tool making appears to have been associated with changes in the brain necessary for language development Hypoglossal Canal
-the nerve that passes through the hypoglossal canal controls tongue movement, and complex tongue movements are involved in spoke language -members of the genus homo after about 500,000 years ago have an enlarged hypoglossal canal. Archaic homo sapiens -found in northern Africa and western Europe -aka homo antecessor and homo hiedelbergensis -possible ancestor of both modern homo sapiens and neandertals -associated with sites such as terra amata and atapuerca Levalloisian technique Tool-making technique by which three or four long triangular flakes were detached from a specially prepared core -developed by humans transitional from homo erectus to homo sapiens
Neanderthals -people living from 125,000-30,000 years ago in Europe and southwestern asia -with brains the size of modern humans evidence indicates Neanderthals were nowhere near as brutish and apelike as originally portrayed -some scholars now see them as the archaic h. sapiens of Europe and southwest asia, ancestral to the more derived, anatomically modern populations of Europe and southwest asia of the last 30,000 years. Physical features
-occipital bun (large projection at the back of skull) -supraorbital torus (browridge) -low forehead, mid facial prognathism, bareel shaped rib cage and robust limbs suggest cold climate adaptation Middle Paleolithic Culture -adaptation to the environment by homo from the middle paleolithci were both biological and cultural, but the capacity for cultural adaptation was superior to earlier members of the genus homo -in addition to the Levalloisian traditions, the middle Paleolithic also included the development of the Mousterian tradition Mousterian tradition -tool making tradition of the neaderthals and their contemporaries of Europe, western asia, and northern Africa -named after the neadertal site of le moustier, france -tools were lighter and smaller than the Levalloisian and included hand axes, flakes, scrapers, borers, wood shavers and spears culture of Neandertals -made objects for symbolic purposes -engaged in ceremonial activities Tuesday, September 20, 2011 Study Review Thursday, September 22, 2011 Cro-Magnons: 1st anatomically modern humans • The remains of ancient people who looked more like contemporary Europeans than neandertals were discovered in 1868 at Les Eyzies in France, in a rock shelter together with tools of the upper Paleolithic. • Consisting of eight skeletons, they are commonly referred to as Cro-magnons, after the rock shelter in which they were found. • Cro-Magnons resemble later populations: in braincase shape, high broad forehead, narrow nasal opening, and common presence of chins their faces
• Defining • • •
Like Neandertals, their brow ridges… Modernity Defining what is “anatomically modern” is surprisingly difficult. If we rely on the brain sizes of modern people, this had already been achieved by archaic H. sapiens Neandertals had average brain size 10% larger than modern population and using the reduction of body size is also not helpful because there are modern populations that are as robust as Neandertals Defining modernity in terms of culture also raises some questions Behavioral modernity is often associated with the new technologies
and expressive arts of the upper Paleolithic Upper Paleolithic • Upper Paleolithic tool kits are known for a preponderance of blade tools, with flint flakes at least twice as long as they are wide • The earliest blade tools come from sites in Africa • The upper Paleolithic archaeological record also contains a proliferation of expressive arts such as portable figurines and cave art. The Human origins debate • Some propose that neandertals, evolved into anatomically modern versions of homo sapiens as different features of modern anatomy were carried to them through gene flow. Multiregional model • Other propose that anatomically modern humans with superior cultural capabilities appeared first in Africa about 200,00 years ago, replacing existing archaic forms as they spread from Africa to the rest of the world. African Origin Model Multiregional evolution model • Argues that some, or all, of the genetic variation between the contemporary human populations is attributable to genetic inheritance from hominid species or sub species of the genus Homo, that were geographically dispersed throughout Asia, Europe, and Australasia, prior to the evolution of anatomical modern humans • Candidate populations suggested by multi regionalists as sources for such genetic variation include Asia h. erectus African Model
Sorting • • •
Argues that all contemporary species of genus homo became extinct after the exodus of anatomically modern humans out of Africa. These extinct human ancestors were too genetically and culturally different to interbreed with modern human or were out competed due to inferior technology the Evidence Morphological features (a mosaic of features could indicate gene flow; stable differences would indicate no gene flow) Genetics (shared dna and mtDna could suggest gene flow; dna and mtdna uniqueness would suggest no gene flow)
Archaeology (shared cultural traits may indicate interaction; distinct cultural traits would indicate little to no cultural change) Mosaic of anatomical features • Some neandertals have features associated with modern humans example a higher forehead, smaller brow ridges, and chins • The earliest anatomically modern human skulls from Europe often exhibit features reminiscent of neandertals. • Some typical neandertal features such as the occipital bun are found in diverse living populations today such as bushmen from southern Africa, finns and lapps from Scandinavia Mitochondrial DNA and the African Eve Hypothesis • Analysis of the mitochondrial DNA of all living humans can be traced back to a “mitochondrial eve” who lived in Africa some 200,000 years ago • If this is the case, all other populations of archaic H. sapiens, as well as non-African H. erectus, would have to be ruled out of the ancestry of modern humans. Neandertal Mitochondrial DNA • The mtDNA of neandertals differs substantially from modern Europeans. • However, the average differences are not as great as those seen among living subspecies of the single species of chimpanzee Mousterian and Aurignacian traditions • Between 30,000 and 36,500 years ago, upper Paleolithic industries developed from the Mousterian tradition of European neandertals.
These new neadertal industries co-existed with the Aurignacian industry, usually associated with anatomically modern humans. Upper Paleolithic technology • Upper Paleolithic tool kits are known for a preponderance of blade tools, with flint flakes at least twice as long as they are wide • Earliest blade tools come from sites in Africa • Pressure flaking was used to press off small flakes as the final step in stone tool making • Burins were used to work bone, horn, antler, and ivory into fishhooks, harpoons, and eyed needles Blade techniques During the upper Paleolithic, a new technique was used to manufacture blades • The stone is worked to create a striking platform; long almost parallel-sided flakes than are struck around the sides, providing sharp-edged blades • Solutrean bifaces of Europe were made using the pressure technique. Tools such as eyed needles and harpoons began to be manufactured out of bone as well Spear throwers • Spear-throwers (atlatls) allowed upper Paleolithic people o throw spears from a safe distance while maintaining accuracy • Upper Paleolithic artists combines artistic expression with function, ornamenting spear-throwers with animal figures Lascaux cave • These 17,000 year old images, painted on a wall in the multi chambered Lascaux cave in the Dordogne region of southwest France, were discovered in 1940 by 4 French kids Venus figurines • Made of stone, ivory, antler or baked clay • Found from France to Siberia • Possibly used as fertility figures Habitation of Australia and new guinea • This figure represents the coastlines of Sahul and Sunda now and in the past •
As sea levels rose with melting glaciers, sites of early human habitation were submerged under water. Spread of upper Paleolithic peoples • Expanded into regions previously uninhabited by their archaic forebears • Colonization of Siberia began 42,000 y.a. • 10,000 years later they reached the northeastern part of that region Habitation of the Americas • Arctic conditions and glaciers in northeastern Asia and northwestern north America provided opportunities and challenges for ancient • people spreading to the Americas • The arctic conditions provided a land bridge (Beringia) between the continents, yet harsh environmental conditions pose considerable challenges to humans. Bipedalism • The move to bipedal mobility is the most important evolution change that has happened to hominims
Thursday, September 22, 2011 Who came up with the theory of inheritance of acquired traits? Jean-Baptiste Lamarck Natural selection is best measured through? Reproductive success Four forces of microevolution? Natural selection, gene drift, gene pool, mutation One defining characteristics of primates compared to other mammals is a large? Brain or braincase One characteristic of primates is a generalized set of teeth suited to omnivory. This is called what? Heterodonty Name four great apes? Gorillas, chimpanzees, orangutans, bonobos Paleoanthropologists use observations of the living apes in order to shed light on the life ways of our ancient primate history?
Primate analogy or primatology The ability of the great apes and some monkeys to not only invent tools but to share the skill with others is a sign of what? You found a skull with a (Foramen magnum) centered and forward on the skull, so you deduce that it is bipedal. Oldowan tools are associated with homo (habilis) Use of fire is associated with homo (erectus) Lucy is an example of the species? • Australopithecus afarensis Time before writing? Pre historic Four types of material culture? Artifacts, manuports, ecofacts, features Traits originate from a common ancestor? Homologous Evolution of wings in birds and bats is an example of? Convergent Painting found in (Lascaux) cave demonstrate art from 17,000 years ago. Test • Multiple choice • Short answer (paragraph) • Matching Bulleted review list on angel for study guide. Yellow box has key words in book. Habilisk, afarensis, important species