Exam 2 study guide

here are three prominent tendencies in the order Primates: arboreal adaptation, dietary plasticity, and parental investment. Describe the biological and/or social characteristics associated with each tendency.

- Arboreal adaptation- Primates get around in trees using an unusually wide range of motions involving the limbs and body trunk. That is, the bones making up the shoulders, limbs, hands, and feet tend to be separate. These separate bones are articulated at highly mobile joints. Atop the list of separate bones is the collarbone (the clavicle), which acts as a strut, keeping the upper limbs to the sides of the body. The lower forelimb (the ulna and radius) and the fingers and toes (the phalanges) also have separate bones. The forearm rotates from side to side with relative ease, and the dexterity of the hands and feet is unparalleled among mammals. One of the most important attributes of the primate hand is the opposable thumb—on either hand, the tip of the thumb can touch the tips of the other four fingers. Thus, the primate can grasp an object or manipulate a small one. Many primates also have opposable big toes (the halluces). The body trunk of primates is also distinctive. The backbone has five functionally distinct types of vertebrae—from top to bottom, the cervical, thoracic, lumbar, sacral (forming the sacrum of the pelvis), and coccyx vertebrae—which give primates a greater range of movements than other animals have. The body trunk also tends to be vertically oriented, such as when the primate climbs, swings from tree limb to tree limb, or sits. The ends of the fingers and toes are highly sensitive in primates. This enhancement helps inform primates about texture and other physical properties of objects, such as potential food items. On the inside surfaces of the fingers and toes and on the palms and soles, respectively, of the hands and feet, the skin surface is covered with series of fine ridges called dermal ridges (fingerprints and toe prints). These ridges further enhance the tactile sense, and they increase the amount of friction, or resistance to slipping, when grasping an object, such as a tree branch. On the backs of the ends of the fingers and toes, most primates have flat nails instead of claws. Made of keratin, the strong protein also found in hair, flat nails may protect the ends of the fingers and toes. They may aid in picking up small objects. Most important, however, they provide broad support to the ends of the fingers and toes by spreading out the forces generated in the digits by gripping. The enhanced vision of primates stems from two developments in the order's evolutionary history. First, very early in primate evolution, the eyes rotated forward from the sides of the head to the front of the head (Figure 6.7). As a result, the two fields of vision overlapped, providing the primate with depth perception. Second, color vision evolved. Crucial for spotting insects and other prey within the surrounding vegetation, color vision likely evolved as early primates shifted from a nocturnal adaptation to a diurnal adaptation. For most primates, enhanced vision led to greatly reduced senses of smell and hearing. Most primates have lost the rhinarium (the external wet nose, which most mammals have) and the long snout. The reduction in snout length resulted from a loss of internal surface area of the nasal passage, the location of the chemistry involved in smell. -Dietary Plasticity- One fundamental anatomical feature in primates that reflects their high degree of dietary diversity is the retention of primitive dental characteristics, especially of four functionally distinctive tooth types: incisors, canines, premolars, and molars. Over the course of the order's evolution, primates' teeth have tended to reduce in number. The premolars and molars of primates have undergone little evolutionary change compared with those of other mammals. Specialized attributes of some primates' teeth reflect particular food preferences. most primates' incisors are flat, vertically oriented, and used to prepare food before it is chewed by the premolars and molars, The horizontally oriented canine is one of three different kinds of canines in primates. The small, vertical, incisor-shaped canine appears only in humans, and only in humans (and all their hominin ancestors) are the canines subject to wear at the tip of the tooth. The projecting, pointed canine is present in all monkeys and all apes. the large upper canine provides a strong social signal for establishing and maintaining dominance among male members of the primate society, such as in baboons. Thickness of tooth enamel varies across primate species. Orangutans and humans have thick enamel, whereas chimpanzees and gorillas have thin enamel. Thick enamel reflects an adaptation to eating tough, hard foods. -Parental Investment- Female primates give birth to fewer offspring than do other female mammals. A single female primate's births are spaced out over time—sometimes by several years in the cases of some apes. Primate mothers invest a lot of time and energy in caring for each of their offspring. By caring for their offspring, providing them with food, and teaching them about social roles and social behavior generally, primates increase the chances of their species' survival. Primates have long growth and development periods, in part because of their high level of intelligence relative to other animals (Figure 6.16). That primates' brains are so large and complex reflects the crucial importance of intelligence— brainpower—in primate evolution (Figure 6.17). The back portion of the brain where visual signals are processed is expanded in primates, whereas the areas of the brain associated with smell (olfactory bulb) and hearing are considerably smaller than in other mammals.

How do male and female primate reproductive strategies differ, and how do these differences relate to sexual dimorphism?

- Males- physically compete for access to reproductively mature females, resulting in a strong degree of natural selection in males for both large bodies and large canines. This form of natural selection is called sexual selection. Another male strategy is infanticide, the killing of a nursing infant, primarily by a foreign male that has driven the single male out of a one- male, multifemale group. the new male kills the nursing infant so that its mother stops lactating, resumes ovulation, and becomes sexually receptive to him. As a result, the new male enhances his reproductive fitness, largely at the expense of the previous male. -Females- females compete with each other for resources that enable them to care for young. In various New World and Old World monkeys, including macaques and some baboons, the competition for resources happens within the context of stable dominance hierarchies. Higher- ranked females provide more resources than low- ranked females do. How it relates to sexual dimorphism: The males who have larger bodies and canines have more access to females, therefore passing down these attractive traits to their offspring.

Since males and females have different reproductive strategies, they also establish their rank in the dominance hierarchy differently. How do males and females become high-ranking in their societies?

- Males- the alpha or most dominant male has successfully defeated all other males in a series of aggressive encounters. The second- rank male is in second rank because he has defeated all but the dominant male, and so on down the line to the least- dominant male, who has defeated no other male in an aggressive encounter. -Females- hierarchical ranks usually pass from mother to daughter, and younger sisters usually rank higher than older sisters. The younger sister is protected more by the mother than is the older sister, therefore giving the younger sister a higher rank. The mother maintains her rank above all of them, except when the juvenile offspring become adults. Higher- ranked females also tend to have more offspring, such as in gelada baboons in East Africa. In some primates, higher- ranked females have a greater number of offspring because they begin mating and producing offspring months before lower- ranked females. For example, dominant yellow baboons in Kenya start reproducing some 200 days before lower- ranked ones.

Describe the difference between relative and absolute forms of dating. Be able to discuss examples of each.

- RELATIVE DATING- the science of determining the relative order of past events (i.e., the age of an object in comparison to another) A. stratigraphic correlation- The process of matching up strata from several sites through the analysis of chemical, physical, and other properties. For example, any volcanic eruption produces ash with an individual and highly specific chemical signature. The eruption's force, together with powerful winds, can spread the ash over hundreds or even thousands of kilometers, as when Krakatoa, an island volcano in Indonesia that erupted in 1883, sent ash as far as 6,000 km (3,700 mi) away. When an ash layer exists above or below a fossil, that fossil can be judged younger or older than the ash, depending on their relative positions. B. chemical dating- Dating methods that use predictable chemical changes that occur over time. -fluorine dating- A relative (chemical) dating method that compares the accumulation of fluorine in animal and human bones from the same site. Fossils that have been in the soil longer will have absorbed greater quantities of fluorine. The amount of fluorine in them will be much greater than in the bones near the top. C. biostratigraphic dating- A relative dating method that uses the associations of fossils in strata to determine each layer's approximate age. the forms of specific animals and plants change over time, so the forms discovered within individual layers can help determine relative ages. -index fossils- Fossils that are from specified time ranges, are found in multiple locations, and can be used to determine the age of associated strata. D. Cultural dating- the presence of a certain kind of tool enables paleontologists to say that the site (and its hominin occupants) dates to a certain age. -ABSOLUTE DATING- Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. A. dendrochronology- A chronometric dating method that uses a tree-ring count to determine numerical age. B. radiocarbon dating-The radiometric dating method in which the ratio of 14C to 12C is measured to provide an absolute date for a material younger than 50,000 years. the longer since the death of the plant or animal, the greater the amount of 12C relative to 14C. C. radiopotassium dating The radiometric dating method in which the ratio of 40K to 40Ar is measured to provide an absolute date for a material older than 200,000 years. During a volcanic eruption, the heat is so extreme that it drives off all argon gas in the rock. The 40K solid that is in the rock sealed by lava then begins to decay to 40Ar gas, and the gas accumulates, trapped within the rock's crystalline structure. To date that rock—which could then be millions of years old—a scientist measures, with sophisticated instruments, the amount of gas (40Ar) relative to the amount of nongas (40K) in the rock. The more gas there is, the older the rock. D. fission track dating- An absolute dating method based on the measurement of the number of tracks left by the decay of uranium-238. When the isotope decays, fragments produced in the decay, or fission, process leave a line, or track, measuring just a few atoms wide on the rock crystal. Thus, the greater the number of tracks, the older the material being dated. This method can date materials from the past several million years and has been used for dating volcanic ash and obsidian (volcanic glass). E. amino acid dating- An absolute dating method for organic remains such as bone or shell, in which the amount of change in the amino acid structure is measured. Once an organism dies, these l-isomers begin to transform to d-isomers. The longer the organism has been dead, the greater the number of d-isomers, so the fossil's date is based on the ratio of l to d. F. paleomagnetic dating- An absolute dating method based on the reversals of Earth's magnetic field. Because certain metal grains align themselves with Earth's magnetic field as they settle and help form sedimentary rock, geologists can examine the orientation of these fragments to determine the planet's polarity at the time of the rock's formation. In addition, when molten igneous rock is produced, each new layer records the polarity, which can later be determined from the hard igneous rock. G. electron spin resonance dating- An absolute dating method that uses microwave spectroscopy to measure electrons' spins in various materials. Once buried, remains such as bones and teeth absorb radioisotopes and so record the radioactivity in the surrounding burial environment. The older the fossil, the greater the concentration, and this method can date material from a few thousand to more than a million years old. H. thermoluminescence dating- A dating method in which the energy trapped in a material is measured when the object is heated. When such an object is heated—as in an early hominin's campfire—the energy it contains is released as light. The next time that same material is heated—as in the laboratory to derive a date—the amount of light released reveals the amount of time since the material was first heated. This method can date materials back to about 800,000 yBP.

Axial vs. Appendicular

-Axial - the bones of the trunk, including the skull, vertebrae, sacrum, ribs, and sternum. -Appendicular - the bones of the limbs, including the shoulder and pelvic girdles and the hands and feet.

C3 vs C4 plants

-C3 plants Plants that take in carbon through C3 photosynthesis, which changes carbon dioxide into a compound having three carbon atoms; tending to be from more temperate regions, these plants include wheat, sugar beets, peas, and a range of hardwood trees -C4 plants Plants that take in carbon through C4 photosynthesis, which changes carbon dioxide into a compound with four carbon atoms; these plants tend to be from warmer regions with low humidity and include corn, sugarcane, millet, and prickly pear

Cortical vs. Trabecular Bone

-Compact bone - aka cortical; solid, dense bone found in the walls of bone shafts and on external bone surfaces. Compact bone is designed to bear compressive loads. Because it is denser, it can handle greater linear forces. This is why the shafts of your long bones are made up of cortical bone. -Spongy bone - aka trabecular; spongy, porous, lightweight bone with a honeycomb structure. Spongy bone is found under protuberances where tendons attach. So you can find spongy bone in the bodies of the vertebrae, in the epiphyses of long bones, in short bones, and sandwiched between flat bones, such as the bones of the skull. Trabecular bone is named after the thin, bony spicules that form it, trabeculae. trabecular bone is designed to handle lighter forces or forces that come from many directions.

Cranial vs. Postcranial

-Cranial - refers to the skull. -Postcranial - refers to the remainder of the skeleton. Everything below the skull is postcranial.

Tooth Anatomy (Crown, Root, Cusp, Pulp Cavity)

-Crown - the part of the tooth covered by enamel. -Root - the part of the tooth that anchors the tooth into the maxillae or mandible. -Cusp - occlusal projection of the crown. -Pulp cavity - the central soft tissue space within a tooth. Houses the nerves and blood vessels for each tooth.

Enamel vs. Cementum vs. Dentin

-Enamel - specialized hard tissue that covers the crown, approximately 97% inorganic material. Enamel is the hardest substance in the human body. It is this ridiculously high percentage of inorganic material that makes teeth so durable, particularly the crown. -Cementum - bone-like tissue that covers the external surface of tooth roots. -Dentine - the tissue that forms the core of the tooth. Dentine underlies the enamel of the tooth and encapsulates the pulp cavity.

Tooth Types

-Incisors - serve to nip or bite food into manageable pieces. These are your front teeth. -Canines - serve to grasp and capture prey. In humans, canines no longer serve this purpose. You may have noticed that we aren't doing a lot of hunting with our mouths anymore! Instead, canines primarily function as an extension of the incisors. They just retain a more conical shape than incisors. -Premolars and Molars - serve to chop or crush pieces of food further before they are swallowed. Premolars are called bicuspids by dentists, because they have two cusps. Molars are the largest teeth. Their extensive chewing surfaces emphasize crushing and grinding.

What are the four types of teeth, and what function do they serve?

-Incisors - serve to nip or bite food into manageable pieces. These are your front teeth. -Canines - serve to grasp and capture prey.In humans, canines no longer serve this purpose. You may have noticed that we aren't doing a lot of hunting with our mouths anymore! Instead, canines primarily function as an extension of the incisors. They just retain a more conical shape than incisors. -Premolars and Molars - serve to chop or crush pieces of food further before they are swallowed.Premolars are called bicuspids by dentists, because they have two cusps.Molars are the largest teeth. Their extensive chewing surfaces emphasize crushing and grinding.

What are the dietary specializations we see in primates, and what sorts of biological characteristics are associated with each (dentition, body size, specialized stomach, etc.)?

-Insectivores- High, pointed cusps on occlusal surface of molars for piercing; Short, simple gut since nutrients are easy to extract; Small body size - insects are hard to catch, and it would be very difficult to get enough to support a large bodied primate Example: Tarsier (family Tarsiidae) you'll see that the food preparation has to happen with the posterior teeth. When the tarsier actually takes a bite, they're directing the grasshopper to their molars, because the high, pointed cusps let them pierce the exoskeleton. After they've started to break down the hard exterior, they can take bites with their front teeth again. -Folivores- Crests on occlusal surface of molars for shearing; Thin enamel that is easily broken, providing new sharp surfaces; Elongated and complex intestines (perhaps with specialized bacteria) since nutrients are difficult to extract Example: Gorilla (family Hominidae, genus Gorilla) Notice how the gorilla is using his molars to prepare the food and tear the leaves, rather than his incisors. The molars are the only teeth that are sharp enough to get through the tough fibers, which is why folivores need thin enamel that can easily shatter, creating new sharp crests of enamel. -Frugivores- low, rounded cusps on molars for crushing; Thick enamel, prevents it from cracking while chewing seeds; Long, simple gut - nutrients are easy to extract, but allows for maximum absorption Example: chimpanzee (family Hominidae, genus Pan) Since the chimpanzee is eating fruit in this video, you'll notice that she is using her incisors to prepare the food, which is why they are broad and narrow in frugivores. But frugivores also eat seeds and nuts, and if there were any seeds in that orange, she would need the thick enamel on her molars to crack those hard resources. -Gummivores- May have a tooth comb for scraping; Typically small body size since simple sugars alone can't support a large bodied primate Example: pygmy marmoset (family Callitrichidae, genus Cebuella) You can see that the pygmy marmoset has got high cusps on its molars for processing the insect exoskeletons, but their primary focus is gum. Their mandibular incisors tilt forward to scrape the tree bark and get to the sap. -Omnivores- No dietary specializations Example: humans (family Hominidae, genus Homo) We are basically the only omnivorous primates. As a whole, primates have dietary plasticity and can eat many kinds of food, but all other primates do have a specific focus. On the other hand, human teeth? No sharp crests for shearing through fibrous leaves, no thickened enamel for crushing seeds and nuts, no high, pointed cusps for breaking through exoskeletons. We eat whatever we want, and our teeth reflect that!

Bone Cells (Osteoblasts, Osteoclasts, Osteocytes)

-Osteoblasts - bone-forming cells responsible for synthesizing and depositing bone material. Osteoblasts make large quantities of a material called osteoid, an uncalcified organic matrix rich in collagen. Since this matrix is uncalcified, calcification must take place to make bone the hard tissue we recognize. Calcification takes place when crystals of hydroxyapatite are deposited into the osteoid matrix. -Osteocytes - mature bone cells; reside in lacunae (i.e., spaces) and are responsible for maintaining bone tissue. Think of osteocytes as homeowners and lacunae as their plot of land. As a homeowner, you're only going to be responsible for your own yard, right? Well, osteocytes basically perform maintenance in their own little plot of bone. -Osteoclasts - responsible for the resorption, or removal, of bone tissue.Osteoclasts are what make it possible to continue bone formation throughout life. While osteoblasts are creating bone tissue, osteoclasts are removing bone tissue. These opposing processes of bone formation and resorption allow bones to maintain or change their shape and size during growth, and later in life for maintenance.

Paleozoic vs. Mesozoic vs. Cenozoic Era

-Paleozoic-The first major era of geologic time, 545-250 mya, during which fish, reptiles, and insects first appeared. -Mesozoic-The second major era of geologic time, 230-66 mya, characterized by the emergence and extinction of dinosaurs. -Cenozoic- The era lasting from 66 mya until the present, encompassing the radiation and proliferation of mammals such as humans and other primates.

Skull vs. Cranium

-Skull - includes the cranium and mandible. -Cranium - does not include the mandible.

Directional Terms

-Superior - toward the head. In quadrupeds, this is referred to as cranial (from the Greek word for skull - you know I love my root words!). -Inferior - towards the feet, or away from the head. In quadrupeds, this is referred to as caudal (from the Latin "cauda" meaning tail). -Anterior - toward the front of the body. In quadrupeds, this is referred to as ventral (from the Latin "venter" meaning belly). -Posterior - toward the back of the body. In quadrupeds, this is referred to as dorsal (from the Latin "dorsum" meaning back - think about dorsal fins on dolphins!). -Medial - toward the midline. -Lateral - away from the midline. -Proximal - toward the trunk, usually used for limb bones. -Distal - away from the trunk, usually used for limb bones.

What are the forms of locomotion that we see in primates, and what are the biological characteristics associated with each (arm to leg length ratio, body size, etc.)?

-Suspensory locomotion - when all four limbs are used to grasp on to branches and help move the body from one tree or branch to another, may have a prehensile tail. Very long forelimbs (i.e., arms) in relation to the hindlimbs (i.e., legs). primates that use suspensory locomotion look very similar to those that use brachiation, there is just a greater reliance on the legs in suspensory locomotion than in brachiation. You see suspensory locomotion in a lot of New World Monkeys (aka, platyrrhines) -Brachiation - arm-swinging. Skeletal features of brachiation include: long forelimbs compared to hind limbs; long, curved fingers and toes; flexible shoulder; and short, stable lumbar region. All of the skeletal features we see associated with brachiation are designed to ensure maximal flexibility in the arms and minimal flexibility in the lower back (so that nothing is accidentally hurt while swinging). the scapula of a brachiator actually sits across the back rather than on the sides, and this is to allow brachiators to have a full range of motion in their arms.you can see a gibbon using brachiation. -Terrestrial quadrupedalism - walking on four limbs on the ground. Skeletal features associated with terrestrial quadrupedalism include: same length limbs; and long and flexible lumbar region. For quadrupedal primates, you'll notice that the scapula is more on the side of the body than across the back. This orientation allows them to move their arms very quickly in a pendulum-style (back and forth), but does not provide much flexibility in terms of side-to-side movement. The body can bend during running, which alternatively moves the feet from being directly under the body mid-stride to full extension, and this propels the body forward to create more momentum and speed. Ex.Baboons. -Knuckle-walking - strong arms used to support upper body weight; larger body size.Knuckle-walking is a form of terrestial quadrupedalism, in that they are walking on the ground using all four limbs. However, rather than walking on their palms like most quadrupeds do, knuckle-walkers place the weight of their upper body onto the second (i.e., intermediate) phalanges of their hands. they will place all of their weight on the flat surfaces created by the intermediate phalanges of their fingers. Because knuckle-walkers put so much pressure on their fingers and wrists, the joints in their hands have to be very tight during locomotion. Knuckle-walking is typically used in primates with larger body sizes, like the Great Apes. Knuckle-walking is most common in gorillas and chimpanzees, although you see a specialized form called fist-walking in orangutans where they (you guessed it!) curl their hands into fists and put all their weight on the first (i.e., proximal) phalanges instead of the second. -Arboreal quadrupedalism - walking on four limbs in the trees. Skeletal features associated with arboreal quadrupedalism include: forelimbs almost as long as hind limbs; and flexible lumbar region. The main difference between terrestrial quadrupeds and arboreal quadrupeds is body size. Arboreal quadrupeds tend to be smaller so that their weight is more easily supported on small tree branches. Arboreal quadrupeds also have slightly longer legs than arms, to give them more jumping power from branch to branch. Ex. uakari monkey. -Vertical clinging and leaping - form of locomotion in which the back legs propel the primate forward. Skeletal features associated with vertical clinging and leaping include: long hind limbs provide powerful spring; and large hands. The most common example of vertical clinging and leaping in the order Primates comes from the strepsirrhine side - the lemurs! Lemurs have got incredibly long back legs designed to provide a powerful push off. In the trees specifically, this allows them to cross great distances, while their large hands enable them to get a better grip on the landing.

Adapids vs. Omomyids

-adapids-Euprimates of the Eocene that were likely ancestral to modern lemurs and possibly ancestral to anthropoids. Adapids were about the same size as some modern lemurs. One of the largest, Notharctus, weighed about 7 kg (15 lb). Adapis, known from many skulls and other parts of the skeleton, weighed a little more than 1 kg (2 lb). The adapids' incisors were flat and vertical, similar to those of many living anthropoids. In addition, like anthropoids, adapids had pronounced sexual dimorphism in body size and in canine size, some had lower jaws with two fused halves, and some had relatively short foot bones. -omomyids Eocene euprimates that may be ancestral to tarsiers. The omomyids differed from the adapids in having large and projecting central lower incisors, small canines, and wide variation in the other teeth. Unlike most adapids (and sometimes like living tarsiers), omomyids had a short skull, a short and narrow snout, and large eye orbits. Their large eye orbits held huge eyes adapted for night vision. Like the adapids, the omomyids consisted of widely diverse species and have left behind a great number of fossils, facts that speak to their high degree of success throughout the Eocene epoch.

Why are Euprimates better candidates for the first true primates than Plesiadapiforms? Discuss anatomical features in your answer.

-in contrast to primates, the plesiadapiforms lacked a postorbital bar and convergent eye orbits, their digits were not especially well adapted for grasping tree branches (they lacked opposability), their digits lacked nails (they had claws), their teeth were highly specialized (some even had three cusps on their upper incisors, as opposed to the single cusp of most primates today), and their brain was tiny (Figure 9.5). Moreover, some plesiadapiforms lacked the auditory bulla, a part of the temporal bone that contains the middle-ear bones and is present in all primates. -Unlike the plesiadapiforms, adapids and omomyids had clear primate characteristics: the postorbital bar and convergent eye orbits, long digits with opposability for grasping, digits with nails (not claws), nonspecialized teeth, and a large brain relative to body size. These features indicate that vision was essential to their adaptation, they were agile and tree-dwelling, their diet was not as specialized as that of the plesiadapiforms, and they were smarter than the earlier animals.

Primate Residence Patterns (Polygyny, Polyandry, Polygamy, Monogamy, Solitary, Bachelor Groups)

-polygyny - comes from the Greek poly- meaning "many" and -gyny meaning "of or relating to female or women". Think about the word gynecologist, i.e., the lady doctor. This is how I remember that polygyny is one male with "many" "females"! -Polyandry - comes from the Greek -andria meaning "of or relating to men". For this one, think about an android, as in a robot fashioned to look like a man or a human being. So when we put the words together, polyandry simply means one female with "many" "males". -Polygamy - comes from the Greek -gamos meaning "marriage/union". Think about the gametes we learned about in Chapter 3, how these are male and female sex cells that will come together or unify to create a new organism. When you break down the terms, polygamy means "many" "unions", in that the males and females all have multiple partners in this primate society. -Monogamy - this has the same root word as polygamy, but this time the prefix is from the Greek mons- which means "alone/one". Where polygamy was many unions, monogamy is "one" "union". -solitary, aka Dispersed Polygyny - solitary is easy enough to remember, since it implies that the primates tend to live on their own, with the exception of mothers with their children. However, another term for solitary is dispersed polygyny, so let's break this one down. We already know that polygyny means "many" "females". In polygynous primate societies, the single male lives with the multiple females in the same location. However, in dispersed polygyny, a male is most successful if his territory overlaps that of many independent females. In other words, a male is still mating with multiple females, they simply don't live together for the majority of the time!

Power vs. Precision Grip

-power grip- A fistlike grip in which the fingers and thumbs wrap around an object in opposite directions. -precision grip- A precise grip in which the tips of the fingers and thumbs come together, enabling fine manipulation.

How did primates make it to the New World? List the four current theories, discussing the pros and cons of each.

1. . First, platyrrhines evolved from a North American anthropoid, then migrated to South America in the late Oligocene -No evidence supports the first hypothesis—there were no anthropoids in North America during the Eocene or Oligocene. There were various euprimates, but none resembled the platyrrhines in South America during the late Oligocene. 2. Second, platyrrhines evolved from an African anthropoid and migrated across the Atlantic to South America. -Pros- Evidence supports the second hypothesis. There were early anthropoids in Africa (Fayum) beginning in the late Eocene, and they predated platyrrhines but looked remarkably similar to the earliest platyrrhines in South America (for example, they had three premolars). This resemblance indicates that platyrrhines originated in Africa before their appearance in South America. In addition, fossils indicate other similarities between animals in Africa and in South America. 3. Third, platyrrhines evolved from an anthropoid in Africa that migrated south (mainly) on land to Antarctica and then to Patagonia, at the southern tip of South America. -Pros- The strong similarities between Old World and New World higher primates also support the third hypothesis. Migration across Antarctica would be impossible today, of course. However, migration over this major landmass would have been possible through much of the Eocene, when the climate there was much warmer and drier. 4. Fourth, Old World and New World anthropoids evolved independently from different lineages in Africa and South America, respectively. -Cons- Given the strong anatomical resemblance between African higher primates and South American higher primates, it is highly unlikely that anthropoids evolved independently in Africa and South America (Figure 9.15). DNA evidence that shows a strong relationship between Old World and New World higher primates is even stronger proof against the fourth hypothesis. In other words, these two groups did not evolve independently: they both originated in Africa.

What are the three hypotheses for the origin of primates? Be able to list the pros and cons of each.

1. arboreal hypothesis- Smith and Jones hypothesized that primates' defining characteristics were adaptations to life in the trees: grasping hands and grasping feet were crucial for holding on to tree branches, binocular vision allowed much greater depth perception for judging distance in the movement from place to place in the trees, smell was no longer necessary for finding food, and greater intelligence was important for understanding three-dimensional space in the trees. The movement from life on the ground to life in the trees, Smith and Jones surmised, put into motion a series of selective pressures that resulted in the ancestral primate. -Cons- Matt Cartmill challenged the arboreal hypothesis. He pointed out that lots of mammals are arboreal (squirrels, for example), but except for primates none have evolved the entire set of characteristics that define the order Primates. 2. visual predation hypothesis -The proposition that unique primate traits arose as adaptations to preying on insects and on small animals. -Pros- the visual predation hypothesis elegantly explains the visual adaptations, intelligence, and grasping abilities of primates - Cons- it leaves an important question unanswered: What role do the primate characteristics play in the acquisition and consumption of fruit, which many primates eat? 3. angiosperm radiation hypothesis- The proposition that certain primate traits, such as visual acuity, occurred in response to the availability of fruit and flowers after the spread of angiosperms. -Pros- Sussman reasoned that because there was little light in the forest, early primates required visual adaptations for seeing small objects. Moreover, their grasping toes helped the animals cling to tree branches while they picked and ate fruit, rather than having to go back to more secure and larger branches, as squirrels do when they eat nuts.

Dendrochronology

A chronometric dating method that uses a tree-ring count to determine numerical age.

Biostratigraphic Correlation

A relative dating method that uses the associations of fossils in strata to determine each layer's approximate age.

Proprimates

A separate order of early primate ancestors from the Paleocene, such as the plesiadapiforms.

Prehensile Tail

A tail that acts as a kind of a hand for support in trees, common in New World monkeys.

In which ways do primates cooperate with one another, and what purposes do primate social groups serve?

Although competition and dominance are central to primate social behavior, primates are also highly cooperative social animals. About half the size of gorillas and not very dimorphic sexually, chimpanzees hunt in groups of cooperating males, often preying on juvenile monkeys such as red colobus. Chimpanzees also share food after a hunt. In the bonobo community, in contrast, it is the females that are highly cooperative among one another; males are far less so. Some primates issue warning calls to their social group when predators approach. Many primates also groom one another (Figure 7.4). In nonhuman primates, grooming involves one individual picking through the skin and hair of another individual, removing insects or other foreign objects, sometimes eating these materials. Among this practice's functions are bonding two members of a social group, calming the primate being groomed, or appeasing that primate if he or she has a higher position in a dominance hierarchy. the evolutionary benefits of an altruistic behavior to the kin group outweigh costs to the individual acting altruistically. A primate will most strongly and consistently act altruistically when living with relatives. Cooperation has many advantages, but it ultimately provides most primate taxa with their distinctive behavioral characteristic: primates live in social groups. And the primary reason for sociality is probably that while many primates are proficient predators, they are also preyed upon by a range of predators. Under circumstances of increased predation, primates' joining together to defend themselves from predators would seem to be an important form of cooperative behavior. Predation is a very strong selective pressure, and mutual cooperation— sociality— has been favored among primates because of the protection it provides. Sociality also provides access to mates, but the predation- related advantage of cooperation within a society is the underlying explanation for primates' living in social groups.

Fayum Depression, Egypt

Another, somewhat later basal anthropoid is from the Fayum Depression in Egypt. Called Biretia by the American paleontologists Erik Seiffert and Elwyn Simons, it dates to the late Eocene, at about 37 mya. The presence of anthropoid characteristics in the teeth, such as the two-cusped (bicuspid) lower premolars, indicates that this animal, too, represents the beginnings of higher primates. whereas Eocene primate fossils have been found in a wide variety of settings around the world, most of the Oligocene primate fossils have come from one primary region, the Fayum Depression. Spanning about 8 million years of evolution, roughly 37-29 mya, the fossil record consists of a wide and abundant variety of plants and of animals. From these remains, scientists have constructed a detailed picture of the environment in northeast Africa (Figure 9.12). In sharp contrast to the desert landscape of the Fayum today—it is among the harshest and driest places in the world—the late Eocene-early Oligocene landscape was much like contemporary southeast Asia; namely, wet, warm, and tropical. The Fayum's major feature, Birket Qarun Lake, was long the focus for all organisms in the region. In addition to diverse primates, all sorts of animals lived there, including the ancestors of rodents (the earliest porcupines are from the Fayum), bats, hippopotamuses, elephants, crocodiles, and various birds. Plants are also represented by a diverse array of tropical taxa, such as mangroves, water lilies, climbing vines, figs, palms, and cinnamon

Tooth Comb

Anterior teeth (incisors and canines) that have been tilted forward, creating a scraper.

Parapithecids

Anthropoid ancestors from the Oligocene, found in the Fayum, Egypt. The later parapithecids, such as their namesake genus, Parapithecus, are among these early anthropoids, and they retained some primitive characteristics. For example, parapithecids had three premolars. This condition may directly link parapithecids to platyrrhines (which also have three premolars), but having three premolars is more likely the ancestral condition that precedes the divergence of platyrrhines and catarrhines.

Oreopithecids

Around the same time Gigantopithecus emerged, a group of apes called oreopithecids lived in Europe. They appear in the fossil record around 8 mya and disappear around 7 mya. Oreopithecus, the best known of this group, has been found on the island of Sardinia and in coal mines in Tuscany, Italy. (Oreopithecids were also present in Africa at the same time as the proconsulids on that continent.) Its Miocene habitat was dense, tropical forests, and its teeth were highly specialized for eating leaves. Also known as the "Swamp Ape," Oreopithecus was a medium-size primate, weighing an estimated 30-35 kg (66-77 lb), but it had a tiny brain. Its relatively long arms indicate that it was adept at some form of suspensory locomotion, similar to that of a modern gibbon. Some of its hand adaptations foreshadow developments in hominin evolution.

How can we use oxygen isotopes in foraminifera to reconstruct past temperature? How can we use carbon isotopes in bones and soil to reconstruct past diet and habitat?

Because of this close linkage of temperature with biology and chemistry, paleoclimatologists have reconstructed temperature changes for much of the Cenozoic (and before). Some of the best information on climate history—and especially temperature—is based on the study of foraminifera and other ocean-dwelling microorganisms (Figure 8.26). These microorganisms' tiny shells are preserved in sediments on the ocean floor worldwide, and their chemical compositions tell important stories about temperature change over time. While the microorganisms are alive, they ingest two of the three stable isotopes of oxygen, 18O and 16O, from the ocean water. Atmospheric temperature directly affects the water's temperature, which in turn affects the amount of 18O in the water. When temperature declines, the amount of 18O in the water, and therefore in the microorganism, increases. When temperature increases, the amount of 18O decreases. Geologists have taken core samples of sediments from the ocean floor and have tracked the 18O content in the microorganisms within those sediments, producing a record of global temperature change. SOILS: WINDOWS ONTO DIETS AND HABITATS Chemical analysis of the bones and teeth in fossils provides important information about past animals' diets and habitats. The reconstruction of diets and habitats is based on the plants those animals ate. Edible plants use either C3 photosynthesis or C4 photosynthesis. The type of photosynthesis determines how the plant extracts and uses carbon from atmospheric carbon dioxide (CO2). In East Africa, to take one example, C3 plants include trees, bushes, and shrubs associated with a relatively wet, wooded environment; C4 plants are associated with open grasslands typical of tropical savannas. Because C3 and C4 plants extract and use carbon differently, the two stable isotopes of carbon in the plants (12C and 13C) have different ratios. C3 plants have lower ratios of 13C to 12C than do C4 plants (Figure 8.29). That is, the values for the stable isotope ratios are lower for C3 plants than for C4 plants. When animals eat the plants, those ratios are transmitted to the body tissues (including bones and teeth) through digestion and metabolism. Thus, scientists can determine which kind of plant the animal ate based on the ratio of 13C to 12C in the animal's remains. The amounts of 13C and 12C are determined by placing a very tiny piece of bone or of tooth in an instrument called a mass spectrometer. Similarly, the soils in which edible plants grow express different ratios of 13C to 12C. The plant's residue after decay preserves the stable carbon isotopes. Worldwide, the ratios in the soils, like those in the animals, tend to be lower in forested settings than in grasslands. The study of the isotopic compositions of these fossils has greatly informed scientists' environmental reconstructions.

What are the functions of bone, and how does the structure of bone tissue support these functions?

Bones protect and support soft tissues. Bones anchor muscles, tendons, and ligaments. Bones act as the rigid levers that muscles operate to produce movement. Bones function as centers of production of blood cells. Bones are storage facilities for fats. Bones are reservoirs of important elements in the body, such as calcium. Interestingly enough, these two bone types are identical at the molecular and cellular level. It is only the level of porosity that differentiates them! Compact bone is designed to bear compressive loads. Because it is denser, it can handle greater linear forces. This is why the shafts of your long bones are made up of cortical bone. Think about the forces your legs have to bear - they are responsible for holding all of your body weight. But spongy bone is much lighter and more porous. Why would you want lighter bone? What purpose could that possible serve? Well, compact bone is good for bearing linear loads, but what about forces that come from any other direction? Since the molecular structure of cortical bone is pretty much parallel, forces approaching at any other angle are dangerous. But trabecular bone is designed to handle lighter forces or forces that come from many directions. Well, since the epiphyses tend to be broader than the shaft, the force is spread over a larger surface area (look at the spread of the forces in the distal end of the femur in the image above). This helps to dissipate the force that each cubic centimeter of bone is handling. Since the forces being applied to the joints are lessened by this greater surface area, the bone can be less dense and still bear the stress. Why not just have cortical bone everywhere? If it's stronger, wouldn't it make sense to just have it make up the whole skeleton? Well, the structure of cortical bone is primarily parallel. This means it can only handle vertical loads. But the structure of trabecular bone is a weave, with trabeculae running in every direction and criss-crossing all over the place. This means that trabecular bone can handle forces from many different directions.

Fossil Record

Chronological collection of life's remains in sedimentary rock layers. pg.199

Basal Anthropoids

During the Eocene, a group of primates called basal anthropoids, whose fossils have been found in Asia and Africa, had the kinds of characteristics that would be expected in an anthropoid ancestor or even the earliest anthropoid. One of the most interesting basal anthropoids is the remarkably tiny Eosimias (meaning "dawn monkey"), found near the village of Shanghuang in Jiangsu Province, China, and dating to about 42 mya. It is one of a number of eosimiids found in southern and eastern Asia. Based on their observations of the teeth and the skeleton, especially of the foot bones, the American anthropologists Daniel Gebo and Christopher Beard regard Eosimias as the first true anthropoid.

Sivapithecids

Early Miocene apes found in Asia. In Asia, the sivapithecids were the counterpart of Europe's dryopithecids. The best-known sivapithecid is Sivapithecus, an ape ancestor that thrived about 12-8 mya. Whereas chimpanzees and gorillas have thin-enameled teeth, Sivapithecus had thick-enameled teeth, adapted for eating hard, tough-textured foods such as seeds and nuts. Its robust jawbones were similarly adapted. . Sivapithecus skulls are strikingly similar to those of living orangutans, with concave faces, narrow nasal bones, oval eye orbits from top to bottom, projecting premaxillas (the premaxilla is the area of the face below the nose), large upper central incisors, and tiny lateral incisors.

Proconsulids

Early Miocene apes found in East Africa. mostly dating to roughly 22-17 mya. . This means that about a 6-million-year gap exists between the late Oligocene catarrhines (28 mya) and the first Miocene proconsulids (22 mya). As a consequence, the immediate ancestors of proconsulids are a mystery. However, the strong anatomical similarity in skulls and in teeth between Oligocene catarrhines from the Fayum and the Arabian Peninsula and the proconsulids of the Miocene indicates a likely ancestral-descendant relationship between the earlier and later groups. The proconsulids are represented by a diversity of taxa—as many as 10 genera and 15 species—from the early and middle Miocene. In fact, the diversity of proconsulids is much greater than that of living apes today. The skulls and teeth of the Miocene proconsulids were clearly like those of apes in overall appearance. The molars have the Y-5 pattern, and the cusps are wide and rounded for eating fruit. Proconsulids' elbows could straighten only so far, whereas living apes' elbows can extend completely. Proconsulids' feet combined primitive and derived features—some of the anklebones were slender, like monkeys', but the big toes were large, like apes'.

Dryopithecids

Early Miocene apes found in various locations in Europe. Larger than earlier apes—about the size of a chimpanzee—it was first discovered and described by the eminent French paleontologist Edward Lartet (1801-1871) in 1856 in St. Gaudens, southern France. Dryopithecus and its contemporary taxa are known from other European regions, such as Spain, Greece, and Hungary. Dryopithecus resembled living apes in many ways: its canines were sharp and tusklike; its cheek teeth were long and had very simple chewing surfaces, well-adapted for chewing fruit and microscopic studies of cross sections of the teeth enamel indicate that these apes grew slowly. Their brains were larger than those of earlier primates, similar to those of modern chimpanzees. Their long forelimbs, grasping feet, and long, grasping hands were powerful and adapted for arm-hanging and arm-swinging, modern apes' main forms of locomotion.

Gigantopithecus

Gigantopithecus, from India, northern Vietnam, and southern China, dating to about 8-0.3 mya (Figure 9.22). Appropriately named for its massive body, Gigantopithecus is the biggest primate that has ever lived, standing nearly 3 m (10 ft) tall and weighing as much as 300 kg (660 lb)! Its massiveness would have limited this fossil primate to the ground for all its activities. Like some of the other Miocene apes, it had thick-enameled teeth and massive, thick-boned jaws, adapted for eating very hard foods, likely nuts, seeds, fruits, leaves, and stems.

Visual Predation Hypothesis

He hypothesized that the first primate specialized in preying on insects and other small creatures, hunting them in tree branches or in forest undergrowth. Cartmill argued that the shift to life in the trees was not the most important factor in explaining primate origins. Rather, the catching of small prey—using both a highly specialized visual apparatus and the fine motor skills of grasping digits—set primate evolution in motion.

Standard Anatomical Position

In humans, this position is standing, looking forward, feet together and pointing forward, arms alongside the trunk with palms facing forward and thumbs pointing away from the body.

Absolute Dating

In the 1920s, the American astronomer A. E. Douglass (1867-1962) developed the first method for numerically dating objects and events, specifically ones including or involving wood. Widely applicable numerical dating became possible in the nuclear age, after World War II (1939-45). In 1949, the American chemist Willard Libby (1908- 1980) discovered radiocarbon dating, pgs 211

Foraminifera

Marine protozoans that have variably shaped shells with small holes. pg220

Victoriapithecids

Miocene primates from Africa, possibly ancestral to Old World monkeys. Victoriapithecus, a prominent genus of the group, is just the kind of primate that would be expected for the ancestor of Old World monkeys.

Be prepared to discuss what differentiates the groups of primates at each node in the Exam 2 Order Primates Breakdown.

PRIMATES 1. SUB ORDER STREPSIRHINI- In acquiring food, strepsirhines rely heavily on their highly developed sense of smell. Reflecting this focus on smell, they have a rhinarium, enlarged nasal passages, scent glands, and a large olfactory bulb in the area in the front of the brain that controls the sense of smell. They also have the aforementioned tooth comb. Strepsirhines have nails at the ends of their fingers and toes, but the second toe has a toilet claw used primarily for grooming. Virtually all strepsirhines communicate with distinctive calls and mark their travel routes and territory with urine. Most primitive primates. There are a number of behaviors that the strepsirhines share, such as a focus on grooming and relatively simple social groupings. there is considerable variation in the biology and ecology of these highly diverse primates, associated with habitats and available foods, terrain, and climate. A. Loris- Lorises today are found in Southeast Asia, Sri Lanka, and Africa. Lorises are less diverse and are represented by far fewer species. They are generally nocturnal and arboreal, Unlike many other strepsirhines, lorises lack an external tail. The very large, forward-facing eyes of lorises are an adaptation to their limitation to nocturnal activity. Their limbs are relatively long, but with some having specializations, such as opposability of the big toe with the other four toes, providing stability on branches and for acquisition of food. Generally, multiple males compete for access to a single female. At dusk, lorises emerge from their nests. Over the course of the night, lorises interact regularly and sleep in groups. During the day, females and young sleep in groups. Food sources are limited primarily to insects. B. Lemurs- Lemurs express the highest degree of diversity among primates today, so much so that they represent some 21% of primate genera worldwide. lemurs are restricted to the large island of Madagascar off the southeast coast of Africa. Today, there are about 100 taxa of lemurs, ranging from the tiny mouse lemur (Microcebus berthae), weighing only about 30 g (1 oz), to the indri (Indri indri), weighing around 9 kg (20 lb). They are extraordinarily primitive, having very small brains relative to body size and enhanced sense of smell. Their high degree of anatomical diversity is also reflected in some species having relatively long hind limbs, an anatomical specialization used for leaping from tree branch to tree branch. Lemurs are highly social, traveling in groups dominated by adult females. Reflecting their biological variation, lemurs have considerable dietary variation, with most depending on leaves and fruits, but with some having a relatively narrow diet. C. Galagos (Bushbabies)- Galagos (or bushbabies) live in Africa. galagos feed and reproduce at night. Their most distinctive physical characteristics—very large, forward-facing eyes and very large eye orbits—reflect an adaptation that is exclusively nocturnal. They also have the specialized tooth comb. Their diet is highly insectivorous, but includes occasional consumption of small animals and fruit. Like many other strepsirhines, the common social grouping includes an adult female and her young. Perhaps most distinctive about galagos is their predilection to jumping upwards, often to heights exceeding 2 m (6 ft). Therefore, a considerable ∼25% of their overall body mass is muscle in the hind limbs. Their remarkably powerful hind limbs facilitate movement over great distances in a short amount of time. 2. SUB ORDER HAPLORHINI- haplorhines have larger brains, are more dimorphic sexually in body size and other anatomical characteristics, and have fewer teeth (premolars, in particular). haplorhines' eyes are convergent and enclosed by a continuous ring of bone. Haplorhines also see in color whereas strepsirhines see mostly in black and white. 1. INFRAORDER ANTHROPOIDEA- —platyrrhines, or New World monkeys, and catarrhines. -PARVORDER PLATYRRHINI- Platyrrhine (from the Greek, meaning "broad-nosed") nostrils are round and separated by a wide nasal septum, the area of soft tissue that separates the nostrils. A. New World Monkeys- widespread in Latin America, from southern Argentina to Mexico. arboreal, spending nearly all their time in trees. suspensory locomotion, in which all four limbs grasp on to branches and help move the body from one tree or branch to another. Prehensile tail. diverse diet, ranging from insects (that is, they practice insectivory) to fruits (frugivory) and leaves (folivory). -PARVORDER CATARRHINI- Catarrhine ("hook-nosed") nostrils are close together and point downward. 1. Superfamily: Cercopithecoidea A. Old World Monkeys- are the most diverse and successful nonhuman primates. They inhabit a wide range of habitats throughout Africa and Asia but mostly live in the tropics or subtropics. Some are arboreal and some are terrestrial. have bilophodont upper and lower molars, a narrow face, a sitting pad on the rear, and a long body trunk that terminates with a nonprehensile tail. Their canines are highly dimorphic sexually—males' canines are larger than females' canines, sometimes considerably so. -Colobines- Colobines are closely related, medium-sized primates with a long tail and a wide array of coloration. They are mostly arboreal and live in a variety of climates, though not in dry areas. Colobines are folivores, and their anatomical features have adapted to accommodate a diet rich in leaves. The high, pointed cusps of their molars shear leaves and thus maximize the amount of nutrition obtained from them. Colobines' large three- or four-chambered stomach, resembling a cow's stomach, contains microorganisms that break down cellulose, again to maximize the amount of nutrition extracted from the leaves. Colobines are receiving a lot of attention because some taxa are highly threatened. One colobine species, Miss Waldron's red colobus monkey, is the first primate to have gone extinct in the past five centuries. -Cercopithecines- cercopithecines have rounded, lower cusps on their molars as their diet is rich in fruit, which does not need as much processing to extract its nutrients. cercopithecines are often called "cheek-pouch monkeys" because inside each cheek they have a pouch that extends into the neck and serves as a kind of stomach. While foraging, they store food in their cheek pouches, which are especially useful when they need to gather food quickly in a dangerous area. Arboreal cercopithecines tend to have a longer tail, while terrestrial species have a short or no tail. The most studied cercopithecoids are the cercopithecines, which include baboons and baboonlike monkeys (geladas, mandrills, macaques). Many cercopithecines live in the savannas of East Africa. Some of them have highly dexterous fingers, adapted for picking up small seeds from the ground. 2. Superfamily: Hominoidea- The hominoids are, in addition to humans, great apes and lesser apes. All of these hominoids have large brains, broad faces, and premolars and molars with little occlusal surface relief. They all have a Y-5 lower molar pattern. None of the hominoids have an external tail. A. Apes- Today, the only great ape that lives in Asia is the orangutan. The lesser apes live in Southeast Asia. The great apes of Africa—the chimpanzee, the closely related bonobo (or pygmy chimpanzee), and the gorilla— are restricted to small equatorial areas. All apes have the canine-premolar honing complex. gibbons, siamangs, gorillas, chimpanzees, bonobos, and orangutans—have very long forelimbs (arms) compared with the hind limbs. The fingers and toes are also quite long, for grasping trees and branches of various shapes and sizes. Gibbons and siamangs are skilled brachiators, using their upper limbs to move from tree limb to tree limb. Chimpanzees, bonobos, and gorillas are efficient at various suspensory postures, but their large sizes—especially in adult males—lead them to spend significant amounts of time on the ground in feeding and in locomotion. They use a specialized form of quadrupedalism called knuckle-walking, in which the very strong arms are used to support the upper body weight while positioned on the backs of the fingers' middle phalanges. The knuckles bear the weight, while the fingers are flexed toward the palms. In orangutans and gorillas, males have enormous masticatory muscles, which are accommodated by a large, well-developed sagittal crest, the ridge of bone running along the midline (mid-sagittal) plane of the skull. The sagittal crest is the terminal attachment site for the temporalis muscle. Gorillas devote considerable time to eating leaves and plant stems. In contrast, chimpanzees are omnivorous—they eat fruit, leaves, bark, insects, and meat, depending on the season, their habitat (ranging from dense rainforests to savanna-woodlands), and local tradition. When meat is not available, chimpanzees' body weight goes down, suggesting that they rely on animal sources for protein. B. Humans- Humans' general body plan resembles that of the large-bodied apes of Africa, Humans have several unique anatomical attributes, however, many of which are related to the fact that humans are the only obligate, or restrictedly, bipedal primate. In bipeds, the foramen magnum—the large opening for the passage of the spinal cord to the brain—is located at the bottom of the skull. The skull sits atop the body, Many of the postcranial characteristics associated with bipedalism are in the pelvis. The pelvis of the human (the biped) is short and directed to the side of the body, in humans, they abduct the thigh on the side of the hip that supports the body weight when a person walks.

Epochs of the Cenozoic Era

Paleocene 66 mya - 56 mya, Eocene 56 mya - 33.9 mya, Oligocene 33.9 mya - 23 mya, Miocene 23 mya - 5.3 mya, Pliocene 5.3 mya - 2.6 mya, Pleistocene 2.6 mya - 12 kya, Holocene 12 kya (thousand years ago) - present

Primates

Primates are adapted to life in the trees—they express arboreal adaptation in a set of behaviors and anatomical characteristics that is unique among mammals. Primates eat a wide variety of foods—they express dietary plasticity. Primates invest a lot of time and care in few offspring—they express parental investment. One thing that all anthropologists agree on when they talk about primates is the order's remarkable diversity. pgs 137-140

Altruism

Refers to a behavior that benefits others while being a disadvantage to the individual.

Opposable

Refers to the thumb of primates, in that it can touch each of the four fingertips, enabling a grasping ability.

Sexual Dimorphism

Sexual dimorphism in body size and in canine size is considerably higher in such societies than in societies where males do not compete. This difference reflects the fact that to compete for females successfully, males must be big and aggressive. In these societies, males are generally unrelated. In societies where males are related, live in the group in which they were born (the natal group), and compete with related males, sexual dimorphism tends to be lower than in groups where males disperse and compete with nonrelated males.

Arboreal Hypothesis

Smith and Jones hypothesized that primates' defining characteristics were adaptations to life in the trees: grasping hands and grasping feet were crucial for holding on to tree branches, binocular vision allowed much greater depth perception for judging distance in the movement from place to place in the trees, smell was no longer necessary for finding food, and greater intelligence was important for understanding three-dimensional space in the trees. The movement from life on the ground to life in the trees, Smith and Jones surmised, put into motion a series of selective pressures that resulted in the ancestral primate.

Relative Dating

Steno's law of superposition laid the foundation for relative dating, . That is, the event recorded or object found on the bottom is the oldest, the event or object immediately above it is next oldest, and so forth

Plesiadapiforms

The Paleocene candidate for the first primates is a highly diverse, highly successful group of primitive mammals called the plesiadapiforms, which lived in western North America, western Europe, Asia, and possibly Africa. These animals represent an adaptive radiation that flourished over a 10-million-year period, beginning at the start of the Paleocene. Probably not primates. the plesiadapiforms lacked a postorbital bar and convergent eye orbits, their digits were not especially well adapted for grasping tree branches (they lacked opposability), their digits lacked nails (they had claws), their teeth were highly specialized (some even had three cusps on their upper incisors, as opposed to the single cusp of most primates today), and their brain was tiny. some plesiadapiforms lacked the auditory bulla, a part of the temporal bone that contains the middle-ear bones and is present in all primates.

Euprimates

The first true primates from the Eocene: the tarsierlike omomyids and the lemurlike adapids.

Sexual Selection

The frequency of traits that change due to those traits' attractiveness to members of the opposite sex.

Infanticide

The killing of a juvenile.

Rhinarium

The naked surface around the nostrils, typically wet in mammals.

Dental Formula

The numerical description of a species' teeth, listing the number, in one quadrant of the jaws, of incisors, canines, premolars, and molars.2-1-2-3. pg 144

Steno's Law of Superposition

The principle that the lower the stratum or layer, the older its age; the oldest layers are at the bottom, and the youngest are at the top.

Stratigraphic Correlation

The process of matching up strata from several sites through the analysis of chemical, physical, and other properties. pgs 206

Angiosperm Radiation Hypothesis

The proposition that certain primate traits, such as visual acuity, occurred in response to the availability of fruit and flowers after the spread of angiosperms.

Radiocarbon Dating

The radiometric dating method in which the ratio of 14C to 12C is measured to provide an absolute date for a material younger than 50,000 years.

Radiopotassium Dating

The radiometric dating method in which the ratio of 40K to 40Ar is measured to provide an absolute date for a material older than 200,000 years.

Dominance Hierarchy (concept)

a dominance hierarchy represents how individuals in a primate society are ranked relative to one another. For males, the alpha or most dominant male has successfully defeated all other males in a series of aggressive encounters. The second- rank male is in second rank because he has defeated all but the dominant male, and so on down the line to the least- dominant male, who has defeated no other male in an aggressive encounter. For females, hierarchical ranks usually pass from mother to daughter, and younger sisters usually rank higher than older sisters. The younger sister is protected more by the mother than is the older sister, therefore giving the younger sister a higher rank. The mother maintains her rank above all of them, except when the juvenile offspring become adults. In general, though, the higher the rank in primate societies, the greater the ability to acquire important resources, such as food.

Angiosperm

a flowering plant that produces seeds within a fruit

Propliopithecids

propliopithecids Anthropoid ancestors from the Oligocene, found in the Fayum, Egypt. The propliopithecids consisted of several genera, but Propliopithecus and Aegyptopithecus, both dating to between 32 and 29 mya, are the most common of this group of primates. The propliopithecids had a more derived dental formula of 2/1/2/3, one fewer premolar than the parapithecids had. In this and other respects, they were more catarrhine-like than the parapithecids.

Stereoscopic Vision

refers uniquely to the sense of depth derived from the coordinated use of information from the two eyes.

Kin Selection

the evolutionary benefits of an altruistic behavior to the kin group outweigh costs to the individual acting altruistically. A primate will most strongly and consistently act altruistically when living with relatives. Altruistic behaviors that increase the donor's inclusive fitness; that is, the fitness of the donor's relatives.

Fossils

the remains of once-living organisms. More specifically, they are the remains of organisms that have been wholly or partially transformed into rock through a long process of chemical replacement. In the replacement process, the minerals in bones and teeth, such as calcium and phosphorus, are very gradually replaced with rock-forming minerals like iron and silica.