Evolutionary Anthropology MIDTERM review PDF

Evolutionary Anthropology What do evolutionary anthropologists' study? - Evolutionary anthropologists study the origins, development, and variation of human beings through an evolutionary lens, integrating biological, cultural, and behavioral aspects of humans and their ancestors. Th...

Evolutionary Anthropology What do evolutionary anthropologists' study? - Evolutionary anthropologists study the origins, development, and variation of human beings through an evolutionary lens, integrating biological, cultural, and behavioral aspects of humans and their ancestors. Their goal is to understand how human beings evolved over millions of years, and how both biological and cultural evolution have shaped human populations over societies. What are the 5 research disciplines in evolutionary anthropology? 1. Primatology 2. Paleoanthropology 3. Human variation 4. Medical anthropology 5. Forensic anthropology How do evolutionary anthropologists conduct their research? - They conduct descriptive, casual, and applied research - They formulate and test scientific theories - They test hypotheses using the scientific method The Development of Evolutionary Concepts - Carl Linnaeus - Created the taxonomic system and binomial nomenclature (AD 1707-1778) - Jean-Baptiste Lamarck - "soft inheritance" - He proposed that organisms could change during their lifetimes in response to environmental challenges and then pass these changes on to their offspring - He argued that traits acquired by an organism through use or disuse of body parts could be inherited. For example, he believed that giraffes developed long necks because their ancestors stretched to reach higher leaves, and this acquired characteristic was passed down to future generations - Georges Cuvier - Known for catastrophism (AD- 1744-1829) - He proposed that Earth's geological and biological history was shaped by a series of sudden, short-lived, and violent events, such as floods or volcanic eruptions. According to this theory, these catastrophic events caused the mass extinction of species. - James Hutton - Known for uniformitarianism (AD-1726-1797) - He proposed that the geological processes we observe today (such as erosion, sedimentation, and volcanic activity) have been operating in a similar way throughout Earth's history. - He argued that slow, continuous processes over vast periods of time were responsible for shaping the Earth's landscape - Challenged the theory of catastrophism - Charles Lyell - Also known for uniformitarianism (1797- 1875) - Basically the same but reinforced James Hutton's concept of deep time - Charles Darwin - Known for natural selection ( 1809 -- 1882 ) Darwin's Theory - The ability of a population to expand is infinite, but the environment's ability to sustain that population is finite - Organisms within the population vary, and this variation affects the ability of individuals to survive and reproduce - This variation is transmitted from parent to offspring Key Terms: - Microevolution - A change over generations (time) in the frequency of one or more alleles in the population - Macroevolution - Large-scale change over time resulting in new species (process of speciation) - Genotype - Genetic makeup of an individual. The term can refer to the entire genetic makeup of an individual or to the alleles at a particular locus - Phenotype - The physical characteristics of an individual Inheritance and Biological Evolution Key terms: - Chromosomes - These are molecules containing genes - Mitosis - It's a process called cellular division to replicate cells - Meiosis - Cellular division to create daughter cells with ½ DNA as parent cell - Gamete - Sex cell DNA - Stands for deoxyribonucleic acid - Contains hereditary material in cell - It's a double-helix shape - Composed of 4 nucleotide bases: Adenine, cytosine, guanine, thymine Protein Formation - RNA - A single stranded nucleic acid - Goes through 2 process - Transcription - Process by which genetic information from DNA is transformed into RNA - Translation - Process by which genetic information coded in various forms of RNA is now translated into protein Mutation - A mutation is a change in the nucleotide sequence of DNA - Causes - Can result from copying errors during cell division, exposure to radiation, chemical (mutagens), or viruses - Types of mutations - Somatic cell mutations - These occurs in non-reproductive cells and are not passed to offspring - Germ cell mutations - These occur in reproductive cells and can be inherited by offspring - Mutations can be neutral, harmful, or beneficial to the organism - Role of mutations in evolution - Mutations are the ultimate source of genetic variation within populations, driving evolutionary change Chapter 2: Microevolution and Evolutionary Anthropology Learning goals: - Population genetics - Natural selection - Adaptation What is population genetics? Population genetics is a branch of biology that studies the genetic composition of populations and how it changes over time due to factors such as mutation, natural selection, genetic drift, and gene flow. It combines elements of genetics, evolution, and mathematics to understand the distribution of genetic variations within populations and how these variations can influence traits and evolutionary processes. Key concepts in population genetics include: - Gene pool: the collection of all genetic material in a population, including all alleles (variations of a gene) - Allele frequencies: the proportion of different versions (alleles) of a gene in a population. These frequencies change due to evolutionary forces. - Hardy-Weinburg Equilibrium: a theoretical state in which allele and genotype frequencies remain constant in a population over generations in the absence of evolutionary influences. - Mutation: random changes in DNA that introduce new alleles into a population - Genetic drift: random fluctuations in allele frequencies, particularly in small populations, that can lead to significant evolutionary changes. - Natural selection: the differential survival and reproduction of individuals based on their genetic traits, leading to changes in allele frequencies over time. - Gene flow (migration): the transfer of alleles from one population to another through migration, influencing the genetic diversity within a population. Gene Flow - It's the movement of genes between populations - 2 important outcomes - Increases within-population genetic variation - Reduces between-population genetic variation Natural selection - Acts only on existing variation - Any consistent difference in fitness among phenotypically different biological entities Fitness - In evolutionary anthropology, fitness involves selection for heritable traits - 2 properties: - Involves success of biological entity in producing offspring - Represents average contribution of allele or genotype to succeeding generations. What are the 3 mode of selection? - Directional selection (graph looks like a slight shift to the right or left side) - This process favours either higher or lower values of character. Increases variation between populations exposed to different environments (i.e., = different selection forces) - Stabilizing selection (graph looks like the average (curve) is much higher) - Average phenotype is fittest. Reduces variation within populations - Disruptive selection (graph looks like there are now 2 peaks of the curve and one is shifted to the left and the other to the right) - Both extremes of trait are favoured Are Natural Selection and Biological Evolution the Same? - No, they aren't the same, though they are closely related concepts. Here are the differences: - Biological evolution - It refers to the overall process of change in the genetic composition of populations over time, resulting in the diversity of life seen today. It is the broad concept that includes all the mechanisms by which populations of organisms changes across generations. - Evolution occurs when the frequency of certain alleles (gene variants) in a population changes over time - Evolution can happen due to multiple mechanisms, not just natural selection. These mechanisms include: - Natural selection - Genetic drift - Mutation - Gene flow - It is the long-term process of species changing over generations, leading to adaptation, speciation, or even extinction - Natural selection - It is one specific mechanism of evolution first proposed by Charles Dawin. It describes how certain traits become more common in a population because individuals with those traits are better suited to survive and reproduce in their environment. Adaptation - It is a process and feature - Process: change in organism enabling it to better reproduce and survive in environment. - Feature: characteristic that performs function of utility to organism possessing it. What is behavioral adaptation? - Linked to socio-biology - This is the study of animal behavior based on assumption that genes control behavior - It may work in insects, but not in humans because we have no or few instinctual behaviors - In evolutionary anthropology, behavior seen as trait with genetic and phenotypic components that can be influenced by selective pressures What are the 2 misconceptions on natural selection and adaptation? 1. There is no "perfect design" for any biological entity. Why? Because the environment is always changing. 2. Natural selection and adaptation have no goal. There is no "finish line" for the evolutionary process. How does natural selection influence the evolution of traits, according to the example of the medium ground finches on Daphne Major? - During the drought of 1975-1978, finches with deeper beaks were more likely to survive because they could process the larger seeds available at that time. This led to an increase in the average beak depth in the population, demonstrating directional selection, where environmental changes favor individuals with certain traits. However, deep beaks come with developmental disadvantages, leading to a balance between the advantages and disadvantages. Chapter 3: Macroevolution and Evolutionary Anthropology ' Learning goals: - Understand species concept, speciation, and cladistics (phylogenetics) - Learn how to read a cladogram - Explore how evolution works on a grand scale - Grasp the modern evolutionary synthesis Macroevolution - It refers to large-scale evolutionary changes, such as the formation of new species (speciation) and new taxonomic groups - Macroevolution occurs over geological eras and focuses on major evolutionary transitions Species Concept - Typological species concept: classifies organisms based on similarities in appearance. - Biological species concept: defines species as actually or potentially interbreeding populations that are reproductively isolated from other groups. This concept focuses on reproductive isolation but faces challenges when applied to fossil species. - Phylogenetic species concept: the smallest diagnosable group of organisms with unique character states, which can be applied to both living and fossil species Speciation - The evolutionary process that leads to the formation of new species - It can be adaptive (leading to better survival in a particular environment) or non-adaptive - Intermediate forms are often debated in the speciation process Allopatric Speciation - Speciation occurs due to geographic isolation, limiting gene flow between populations - 2 models: - Vicariant speciation: large populations are split by physical barriers - Peripatric speciation: small, isolated populations diverge from the main population Cladistics - A method for understanding evolutionary relationships through branching diagrams called cladograms or phylogenetic trees - Key assumptions - Lineages change over time - All organisms have a common ancestor - When a lineage splits, it divides into exactly 2 groups - Clade: a group consisting of a common ancestor and all its descendants Evolutionary process of speciation - Evolutionary radiations: rapid diversification of a lineage into multiple forms, often in response to new environments or niches - Phyletic gradualism: evolution occurs at a constant rate, with new species arising gradually from ancestral species. - Punctuated equilibrium: species remain morphologically stable for long periods, with rapid speciation events occurring in between. Modern evolutionary synthesis - Combines insights from genetics, paleontology, systematics, and other fields - Emphasizes the combined action of 4 mechanisms - Random mutation - Natural selection - Genetic drift - Gene flow What is the difference between the biological and phylogenetic species concept? - The biological species concept defines species based on reproductive isolation, while the phylogenetic species concept defines species as the smallest group of organisms diagnosable by unique character states. The phylogenetic concept can be applied to both living and fossil species. What is allopatric speciation, and what are its 2 models? - Allopatric speciation occurs when populations become geographically isolated, limiting gene flow. The 2 modes are: - Vicariant speciation - Peripatric speciation What are the key differences between phyletic gradualism and punctuated equilibrium? - Phyletic gradualism suggests evolution occurs at a constant, gradual rate, while punctuated equilibrium posits that species remain stable for long periods, with rapid bursts of change during speciation events How are homologous and analogous traits different in cladistics? - Homologous traits are inherited from a common ancestor and are useful for determining evolutionary relationships, while analogous traits arise from convergent evolution (similar adaptations in different lineages) and are not used in phylogenetic reconstruction What are the 4 mechanisms of evolutionary change emphasized by the modern evolutionary synthesis? - The four mechanisms are random mutation, natural selection, genetic drift, and gene flow Chapter 4: Living Primates Introduction to primates: - Primates are a diverse order with significant variation in diet, social organization, and activity patterns - Why are anthropologists interested in primates? - Primates help study human evolution due to homology (common ancestry). Humans and nonhuman primates share similar morphological, physiological, and behavioral traits. - Geographic distribution: living primates are found in tropical regions of Africa, Asia, and the America. Fossil primates had a broader distribution. Primate Taxonomy and Traits - Primates are mammals, but they differ from other mammals by having certain traits: - Opposable big toe or thumb: provides a high level of precision in grasping - Flat nails (instead of claws) on atleast one digit - Reduced olfactory system but enhanced stereoscopic vision (depth perception) - Large brain relative to body size - Postorbital bar: bony structure around the eye for protection - Petrosally formed auditory bulla: bone that encloses the inner ear. - Life history traits: - Longer gestation periods - Longer to mature - Greater prenatal investment compared to other mammals Strepsirrhine (Lesser primates) - Characteristics - Dental tooth comb - Moist rhinarium (wet nose for better smell) - Tapetum lucidum (eye structure for better night vision) - Two superfamilies: lemuroidea (Madagascar) and lorisoidea (Africa and Asia) - Lemuroidea: mostly arboreal (tree-dwelling), nocturnal, and dominated by females in social groups. - Lorisoidea: arboreal and nocturnal with some species possessing a toxic bite Haplorhines (Higher primates) - Characteristic - Dry nose and retinal fovea (better vision) - Postorbital closure: full bone protection around the eyes - 2 infraorders: Anthropoidea (monkeys, apes humans) and tarsiiformes (tarsiers) - Tarsiiformes - Only genus: Tarsius (Southeast Asia) - Small body size, large eyes, entirely faunivorous (animal-eating) - Platyrrhines (New World Monkeys - Found in central and south America - Small to medium body size - Some species have prehensile tails (tail capable of grasping objects) - Dental formula: 2.1.3.3. - Catarrhines (Old World Monkeys) - Found in Africa and Asia - Include cercopithecidea (OWM), Hylobatidae (gibbons), and Hominidae (great apes and humans) - Varied diets and social organizations - Dental formula: 2.1.2.3. Primates Dentition and Body Size - Dental formula: represents the number of incisors, canines, premolars, and molars, on one side of the jaw (ex: 2.1.2.3) - Body size - Small primates (tend to weigh less than 500 g) tend to eat insects and gums - Larger primates tend to be frugivorous (fruit-eating) or folivorous (leaf-eating) - **KAY's Threshold**: Primates smaller than 500g generally eat insects, while those larger than 500g eat fruits and leaves - area and volume change at different rates - so if an animal doubles in size, it will be 8 times heavier - small animals have greater heat (energy) loss than larger animals Primate Habitats and Ranging Patterns - Primates inhabit a variety of environments including tropical rainforests, dry forests, savannas, and deserts - Microhabitats in forests - Emergency layer: trees above the canopy - Canopy: main tree layer - Understory: layer beath the canopy - Ranging patterns - Daily path length: distance traveled in a day - Home range: the area regularly used by a primate group - Territory: exclusive area defended by a primate group - Defending a territory helps in securing mates and food resources but has costs like increased energy use Primate Social Behavior and Conservation - Why do primates live in groups? - Advantages: better predator protection, resource defense, and increased access to mates - Disadvantages: increased competition for resources, higher disease transmission, and greater travel/foraging costs - Primate conservation - Habitat disturbance: logging, agriculture, and forest fragmentation - Hunting pressures: includes subsistence hunting and hunting for economic gain Study Questions and Answers: What characteristics define primates and set them apart from other mammals? - Primates have several defining traits including an opposable thumb or toe, flat nails (instead of claws), enhanced vision (stereoscopic vision), a large brain (large neocortex), and a postorbital bar that protects the eyes What are the main differences between Strepsirhines and Haplorhines? - Strepsirhines have a dental comb, moist noses, and are mostly nocturnal, while Haplorhines have dry noses, better visual acuity (due to retinal fovea), and closed orbits (postorbital closure) Explain the concept of KAY's Threshold in primate ecology. - KAY's Threshold is a rule stating that primates weighing less than 500 g typically rely on insects, while primates larger than 500g tend to eat fruit or leaves. Body size is closely related to diet. What is the significance of defending a territory for primates? - Defending a territory allows primates to secure access to limited food resources and potential mates. However, it comes with costs such as energy expenditure, time, and risks of injury. What are some of the advantages and disadvantages of primates living in social groups? - Advantages: better predator protection, more efficient resource defense, and greater access to mates - Disadvantages: increased competition for food, higher risk of predator encounters, and greater susceptibility to disease transmission Describe the main conservation challenges faced by primates - Primates are threatened by habitat destruction (due to logging, agriculture, and forest fragmentation) and hunting, either for subsistence or economic purposes. What are the differences between NWM and OWM? - NWM - Dental formula: 2.1.3.3 - Prehensile tails (some) - Tympanic ring fused to auditory bulla - What is the tympanic ring? - It's a canal that connects the middle ear to the nasopharync, which is the upper part of the throat behind the nose. Its main function is to equalize air pressure on both sides of the eardrum, which is essential for proper hearing. - Parietal bone meets the zygomatic bone - Broad nostrils (side way facing) - OWM - Dental formula: 2.1.2.3 - Non-prehensile tails - Tympanic tube - Parietal bone DOES NOT meet the zygomatic bone - Narrow nostrils (forward facing) Tutorial Quiz Review: TUT 1: - Standard anatomical position - Facing forward, hands and feet apart - What are the planes of reference? - Sagittal plane (straight down the middle = midsagittal plane) - Coronal plan (goes along the side = midcoronal plane) - Transverse plane (cuts body directly in half = transverse plane) - Skull orientation - Frankfurt Horizontal: it is a standard anatomical reference plane used in anthropology, medicine, and dentistry to orient the human skull in a consistent and reproducible position. This is to ensure that measurements of angles, distances, and proportions are reliable across studies and diagnoses. - It is defined as a plane that passes through.... - The upper edge of the external auditory meatus (the ear canal) = its called **porion** - The lowest point of the orbit (the bony socket of the eye), specifically the infraorbital margin = its called **orbitale** - Directional Terms: - Super (cranial) vs Inferior (caudal) - Superior = above or closer to the head relative to another part of the body - Inferior = below or toward the lower part of the body relative to another part of the body - Proximal vs distal - Proximal = a position closer to the point of attachment (usually trunk or center of the body) or origin of the body part - Distal = a point that is farther from the point of attachment or the origin of a structure, particularly in reference to limbs. - Anterior (ventral) vs posterior (distal) - Anterior = refers to something that is towards the front of the body - Ex: the chest is anterior to the spine - Ventral = a term often used interchangeably with anterior in humans, particularly in quadrupedal animals. It refers to the belly side of the body. - Posterior = refers to the back or rear side of the body - Ex: the spine is posterior to the heart. - Distal = refers to a position that is further way from the point of origin or attachment, typically used in reference to limbs. - Ex: the fingers are distal to the elbow because they are farther from the point where the arm attaches to the torso. - Medial vs lateral - Medial = refers to a position toward the midline of the body - ex: the nose is medial to the eyes because its closer to the midline - lateral = refers to a position away from the midline of the body - ex: the arms are lateral to the chest - External vs internal - External = refers to structure that are located on the outer side or surface of the body - Internal = refers to positions or locations within the body, particularly in relation to other structures. - Dentition - Adult human dental formula for each quadrant of the mouth is: 2.1.2.3 - 2 -- incisors, 1-canine, 2-premolars, 3-molars TUT 2: Phylogenetic trees - Internal nodes represent hypothetical common ancestors. They also represent a speciation even when evolutionary trees are constructed using taxa, rather than individuals or populations. - Terminal nodes represents the actual species or taxa being studied - Clades are groups of organisms that include an ancestor and all its descendants. Clades can be identified by cutting the tree at a particular node. - Horizontal branch lengths reflect the relative amount of evolutionary change over time, such as the acquisition of derived traits, including adaptions. - What are phylogenetic trees? - They are graphical representations that illustrate the evolutionary relationships among various biological species or entities based on their evolutionary history. - Constructing phylogenetic trees - Can be done using various methods like.... - Cladistics - Focuses on shared derived characteristics (synapomorphies) to classify organisms and determine evolutionary relationships - Distance matrix method - Calculate the genetic distance between pairs of species and use these distances to build a tree TUT 3: Primate Morphology/Taxonomy - Important terminology - Symplesiomorphic (can be used interchangeably with plesiomorphic) - These are traits that are shared ancestral characteristics that can indicate common ancestry but may not provide precise information about the relationships among more closely related groups. - Basically are ancestral traits - Synapomorphic - Refers to a type of character state in evolutionary biology that is a derived trait shared by two or more groups (clades) that have a more recent common ancestor - Basically are derived traits - Derived traits - Newly evolved in the last common ancestor of a group - Primitive traits - Ancient characteristics retained from a more distant ancestor Study Question: What are some primitive plesiomorphic traits? A. Lactation B. Live birth C. Tapetum lucidum ANSWER: NONE To determine whether the traits listed (A, B, and C) are primitive (plesiomorphic) or derived (apomorphic), let's briefly analyze each trait - Lactation - Not plesiomorphic: lactation is a derived trait specific to mammals (synapomorphic trait of mammals). While some other vertebrates might have similar characteristics (like the secretion of milk-like substance), true lactation is unique to mammals, making it a synapomorphic trait for this group. - Live births - Not plesiomorphic: live births are also derived traits found in many mammals and some reptiles, such as certain species of snakes. This trait has evolved independently in different lineages, so its not considered a primitive or plesiomorphic trait for all vertebrates. - Tapetum lucidum - Not plesiomorphic: the tapetum lucidum is a reflective layer in the eyes of many vertebrates, particularly In some mammals, reptiles, and fish, which enhances night vision. However, this feature is also considered a derived trait because it has evolved in specific lineages (ex: nocturnal animals) and is not a characteristic of all vertebrates. Primate synapomorphic traits - Grasping hands and feet with opposable big toe and/or thumb - Nails instead of claws - Postorbital bar - Larger proportion of brain devoted to vision - Forward facing eyes: stereoscopy and wide binocular visual fields - Reduction in number of offspring (usually 1) - Increased parental investment - Dermatoglyphic ridges Differences between Stepsirrhini and Anthropoidea (Haplorrhini) **Strepsirrhini (lemurs, lorises)** **Anthropoidea (monkeys, apes, humans)** ------------------------------------------------ ------------------------------------------------------------- Unfused mandibular symphysis (chin) Fused mandibular symphysis Unfused frontal bone Fused frontal bone No postorbital plate Postorbital plate + postorbital bar = postorbital closure Grooming claw on second digit of foot No grooming claws Tooth comb (canines & incisors) No tooth comb Greater reliance on olfaction than anthropoids Reduced reliance on olfaction, increased reliance on vision Rhinarium (wet nose) No rhinarium (dry nose) More nocturnal and arboreal species All diurnal except 1 species; arboreal and terrestrial Tapetum lucidum No tapetum lucidum \> retinal fovea What about Tarisers? Strepsirrhine-like Anthropoid-like -------------------------------------------------------------- ----------------------------------------------------- Small Fused frontal bone Nocturnal Parietal postorbital closure Primarily insectivorous No rhinarium, no tapetum lucidum, and no tooth comb Unfused mandible and grooming claw on second and third digit Lemuriformes - Confined to Madagascar - High species diversity Lorisiformes - Splits into galagos and lorises - Galagos - African species - Aka bush babies - Lorises - Asian species Tarsiiformes - Restricted to Asia - Head can turn 180 degrees - Hindlimbs are twice as long as body - They have immobile eyes, larger than brain Platyrrhini -- Callitrichidae - Very small body size - Dental formula: 2.1.3.2 or 2.1.3.3 - Claw-like nails - No prehensile tails - Polyandrous males care for offspring - Twins are common - Arboreal Cebidae - Larger body size - Dental formula: 2.1.3.3 - Some have prehensile tails - Diverse social structures - Small -\> large groups - Diurnal except for Aotus Important distinguishing features between Cercopithecoidea (OWM) and Hominoidea (NWM) - Cercopithecoidea - Narrow nose - Long, narrow trunk - Tails - Bilophodont teeth - Hominoidea ( apes, humans) - Broad nose - Short, wide trunk - No tails - Y-5 molar pattern Cercopithecoidea -\> cercopithecinae (baboons, macaques, guenons) - Primarily frugivorous - Simple stomach - Cheek pouches - Low round cusps - Large range of body size - Terrestrial and arboreal - Arms/legs are the same length Cercopithecoidea colobinae (colobine monkeys, langurs) - Primarily folivorous (leaf eating) - Specialized gut morphology - Sacculated stomach - Chambered stomachs which help to break down vegetables - Sharp cusps - No cheek pouches - Legs longer than arms Hominoidea hylobatidae (gibbons and siamangs) - Pair-bonding - Brachiation - Long arms Hominoidea Hominidae (orangutans, gorillas, chimps, humans) - Sexual dimorphism - Solitary or group-living - Culture TUT 4 : Primate Origins What are the 3 theories on primate origins? - Fred Szalay: arboreal theory - Matt Cartmill: visual predation theory - Robert Sussman: angiosperm co-evolution theory Important years - Paleocene (66 million) - First true primates - Eocene (56 million) - Primate diversity - Oligocene (34 million) - Anthropoid diversity - Miocene (23 million) - Ape diversity - Pliocene (5 million) - Early hominids - Pleistocene (2.5 million) - Homosapiens Paleocene "Primates" - Geography and climate - Genetic evidence for primate origin in Paleocene or earlier - Plesiadapiformes Eocene Primates - Euprimate s - Similar to extant strepsirrhines - Adapoidea: ancestral lemurs? - Omomyoidea: ancestral tarsiers? - Eosimiidae and oligoithecidae: ancestral haplorhines? Oligocene Primates - 3 taxonomic groups: - Parapithecidae - Propliopithecidae - Platyrrhinin - Rafting hypothesis Miocene Primates - 3 sequential sub-epochs for apes: - Early Miocene apes - Mid Miocene apes - Late Miocene apes - Miocene monkeys Miocene: Age of Apes - Morphology - No tail - Y-5 molars - Early to mid-miocene: apes found primarily in Africa - Proconsul (Africa) - Quadrupeds, rain-forest habitat - Mid-to-late Miocene: apes found in Africa, Asia, and Europe - Dryopithecus & Ouranopithecus (Europe) - Sivapithecus (Asia) - Pilopithecus (Asia) - Kenyapithecus (Africa) - Drier habitat