Biological Anthropology exam 2 end of chapter questions

why study primates

Primates are a model to test hypotheses regarding diet, social behavior, and anatomy to reconstruct aspects of how ancestral hominins may have lived Understand how the forces of natural and sexual selection molded our ancestors after the human lineage split from the rest of the primate order Understanding animals habitats, behavior and biology to conserve these wonderful creatures

Vertical clinging and leaping

Primate's body sits upright against a tree trunk and launches up vertically. Animal uses long, powerful hind limbs for jumping to another location.

The right side of the primate brain

takes in everything on the ENTIRE LEFT SIDE OF THE VISUAL WORLD - including overlapping information gathered from BOTH eyes, including information about parallax.

haplorhines

tarsier, old world monkey, ape, hominins

muscles of mastication

temporalis, masseter (zygomatic arch)

juveniles suffer higher mortality in smaller groups

than in larger groups

folivores

have well-developed and sharp shearing crests (think of scissors) for cutting tough leafy material into small pieces

folivores

leaf eaters

endotherm

regulates body temperature internally as opposed to externally (reptiles)

Omomyoids

Smaller in body size Short snout Many were nocturnal Primarily insectivorous Active quadrupedalism and leaping Ancestral to haplorhines?

Callitrichids

(New World Monkey subfamily.) Examples: Tamarin and Marmosets. (Can have twin offspring. Practice paternal and allopaternal (non-biological parents) care.)

Chimpanzees

(Of all non-human primates, shares the greatest genetic similarity between humans.) Most abundant primate, found all across Africa, Eat mainly ripe fruits, but also leaves and insects. Sometimes they eat meat (of monkeys, wild pigs, and young antelope.)

fauna

(e.g. hippos in England = warm climate)

hominins lack

CP3 honing complex

amniotes

embryos develop in a protective pouch

callitrichidae

marmosets and tamarins

Are apes abundant in the late Miocene?

no (few in number)

William "Strata" Smith 1769-1839

principle of faunal succession (law of association)

half-life

time for half of the radioactive isotope to decay

fossil skeleton

(Bone (already ca 70% mineral)) Organic fraction is replaced by mineral salts carried in by groundwater (Surrounding sandy sediment also turned to stone )

principle of cross-cutting relationships

(Hutton). If one layer cuts through another, the one being cut through is older

Miocene Ape Survivors Give Rise to Modern Apes

A few survivors of this event evolved into modern apes.

miocene-pliocene

5mya

visual predation hypotheses for the adaptive origins of primates

(1) Challenges arboreal notion: many mammals are arboreal without having evolved primate traits. (2) Matt Cartmill proposed that primate traits evolved in response to preying on insects and other small creatures. (3) The exploitation of small prey resulted in the primate suite of adaptations. (4) However, this visual predation hypothesis does not explain fruit-eating primates. (Distinctive primate traits evolved as adaptations for stalking and grasping insect prey in the terminal branches of trees.) (grasping hands in non-primates- opossum, tree shrew, raccoon, squirrel) (stereo vision in other predators)

One possibility is an Eocene primate called a basal anthropoid.

(1) Fossils were found in Asia and Africa. (2) Some scientists regard these forms as the first true primates, though of exactly which genus is debated.

Plesiadapiforms

(1) Found in western North America, western Europe, Asia, and possibly Africa (2) Lack postorbital bar and other primate traits (3) Possibly a separate order, but still potentially related to primates

Adapids and omomyids

(1) Notharctus (2) Adapis (3) Widely diverse species, most with small body size (4) May have evolved from proprimates in Paleocene (5) Evolution occurred in period of global warming

angiosperm exploitation hypotheses for the adaptive origins of primates

(1) Randall Sussman proposed that primate traits were a response to the development of fruit-bearing angiosperm plants. (Primates co-evolved with flowering plants, to exploit their products (fruits, flowers, nectar) and the insects that feed on them in a small branch setting.)

Arboreal hypotheses for the adaptive origins of primates

(1) Smith and Jones (2) Primate traits such as grasping hands and binocular vision were adaptations to life in the trees. (3) Moving from the ground to the trees caused selective pressures that resulted in the ancestral primate. (Primate characteristics such as grasping hands and feet, nails instead of claws, and stereoscopic vision evolved as adaptations to the arboreal lifestyle of early primate ancestors) (tree shrew, grey squirrel)

Joint defense of food resources should be profitable when

(1) food items are valuable (2) food sources are clumped in space and time (3) there is enough food within defended patches to meet the needs of several individuals

Ad libitum sampling

(Abbreviated as "ad lib") All-occurrence record of behavioral events, Best for conspicuous events (aggression, mating, etc.)

Gibbon characteristics

(Belong to hominoids.) Frugivorous: (Fruit eaters.) Brachiators, Long arms, (elongated fingers, shortened thumbs, and suspensory shoulders.)

Old world money characteristics

(Belong to infraorder catarrhini ) Catarrhine nose: (narrow nose with nostrils close together and pointing downward), 2 1 2 3 dental formula, Have tails, (but NEVER prehensile tails,) Some species are sexually dimorphic.

Chimpanzees social life

(Live in multi-male, multi-female groups called a) fission-fusion mating system. (Males are sociable with one another, trying to control females, patrol, and hunt.) (Males remain in their birth community their entire lives) male philopatry, Females are more independent (and once reaching sexual maturity at age 12, most females begin to visit neighboring communities, eventually settling there as breeding adults.)

Bonobos community lifestyle

(Males stay in community they were birthed in) male philopatry Females emigrate to new communities once reaching sexual maturity. Females forge bonds together; (females engage in genital-genital rubbing, reducing tensions between individuals.) Hypersexual.

Cebids

(New World Monkey subfamily. Examples) Capuchin and Muriqui (Have prehensile tails.)

Cercopithecines

(Old World Monkey family.) (Examples:) Vervet Monkey and Hamadryas baboon, Semi-terrestrial, Territorial, Cheek Pouches, Ischial callosities (thickened calluses for sitting on the rump, e.g. baboons), Sexual swellings

Colobines

(Old World Monkey family.) (Examples:) proboscis monkey (big, ugly nose) and hanuman langur Leaf eaters: (sacculated stomach for breaking down cellulose in leaves, higher stomach acid content, longer intestines.)

heterodonty

(Our metabolism uses up a lot of energy being homeotherms. So we must consume a lot of food. Mammals have evolved dietary adaptations to cope with this, including HETERODONTY- )4 kinds of teeth, specialized to carry out different chewing functions

Gorillas

(Part of Hominoids.) Largest primates, (Distributed throughout Africa.) Extremely sexually dimorphic (size), Herbivores: (eat leaves, but also fruit), Live in multi-male groups.

Orangutans

(Part of hominoids) (Closest living kin and among the largest-brained animals on Earth), Fruit eaters, Largely solitary (possibly due to spread out fruit). Extremely sexually dimorphic (size), Sexually competitive (explaining sexual dimorphism). (Claim territories for mating opportunities. Feature transient males who are adults that look like adolescents and attempt to mate with females while avoiding confrontation with other adult males.)

Bonobos

(Part of the Hominoids.) (Sometimes called pygmy chimpanzees due to more slender build.) Lesser sexual dimorphism (than most other apes.) (Similar body size, but males have larger skulls and canines.) Eat mainly fruit, (but rely more on leafy plants than chimps do.) (Live in large social communities called) communities.

Miocene Hominoids: Generalizations

(Plentiful and geographically widespread throughout most of the Miocene. Mostly large-bodied like modern great apes. Their evolutionary relationships are poorly understood, and most cannot be clearly linked to any living ape species. Plentiful and geographically widespread throughout most of the Miocene. Much of Eurasia was forested, climate similar to ca. Georgia - Florida today Mostly large-bodied like modern great apes. Their evolutionary relationships are poorly understood, and most cannot be clearly linked to any living ape species. Their diversity declined significantly in the late Miocene, giving rise to comparatively few species of apes today. Why? ?? Colder climate? Reduced forests? Monkeys?, hominin competition? Fossil bias?)

What resources drive social organization?

(Simple view:) Resources are distributed throughout the environment, either even or patchy distributions, females follow the food, males follow the females

the matrix (context is important)

(Skeletons become fossils by absorbing minerals from their surroundings. They will also absorb isotopes and other matter.) The matrix composition is informative for analyzing fossils, and it is critical for the dating of fossils.

impressions

(Some fossils are actually 'impressions' where) the rock hardened around a soft leaf or body. (The soft tissue then decayed and was filled in by minerals of a different color. )

Principle of original horizontality

(Steno). Rock layers are horizontal to start with, non-horizontality is due to subsequent earth movement

It would seem reasonable that species that occupy the same space would compete with one another for resources, however there are alternatives to this theory. What?

(Sympatric species (those that live in the same space) eventually diverge from one another (niche separation)) One species may have a different diet from the other.

principle of faunal succession

(William Smith). Deeper fauna is older. Layers have "typical" or "index" fossils. A fossils that disappears (goes extinct) doesn't come back later

where do Old world monkeys live

(anthropoids, haplorhines) Live in parts of Africa and Asia. (Also known as cercopithecoids or catarrhines.)

where do New world monkeys live

(anthropoids, haplorhines) live in the tropical and subtropical forests in the "new world," (the western hemisphere. (Americas) Also known as ceboids or platyrrhines.)

intermembral index

(forelimb/hindlimb) x 100% (chimpanzee- 110%, human 70% ---> increased stride length)

Lorises

(found only in mainland Africa and tropical Asia) Loris, galago (bushbabies)

anterior teeth

(incisors and often canines) are primarily concerned with ingestion- transfer of the food from the outside world to the oral vanity in manageable pieces

(dating the Pleistocene) Luminescence dating

(optically stimulated luminescence) electron trap technique that uses light to measure the amount of radioactivity accumulated by crystals in sediments (such as sand grains during burial) (Energy added from soil radiation moves electrons in (crystal out of usual quantum level Crystals contain imperfections that can "trap" superenergized electrons Heating (to above 300 degrees) or sunlight can empty or "zero" the traps, allow measurement of "trapped charge" Determining "annual dose" of radiation from soil allows conversion of "trapped charge" to age (Geiger counter or dosimeter) Optically stimulated- or thermo-luminescence OSL or TL Can date pots, hearths, burned flints, sands Limits determined by amount of soil radiation and number of "traps" in material -usually 0-200 kyr Problems - intermediate heating, non-homogenous materials, changes in "annual dose" due to groundwater or leaching of U))

cheek teeth

(premolars and molars) are involved in the subsequent breakdown of food items by chewing Cheek teeth break down food mechanically by: Puncture crushing or piercing food with sharp ridges (cusps) Crushing and grinding food in a mortar-and-pestle fashion between rounded cusps and flat basins

Essentially, everything comes down to food. The classic model is that females are influenced most by the distribution of food

- because females need enough food to support themselves and their offspring - how they distribute themselves on the landscape, and what relationships they form with other members of their species, is determined by the distribution of food.

In what specific ways does the skeleton of a biped reflect its form of locomotion?

-S-shaped spine -center of gravity is at the back closer to the hips+ -body weight presses down on the spine to the sacrum, to hips, onto the 2 legs -foramen magnum: where the skull balances (pg. 245)

once a sensory channel

-such as color vision- is elaborated, can be used for many different purposes

Major evolutionary novelties of humans

1) Habitual upright walking (bipedalism) 2) Characteristics of the dentition 3) Less canine/premolar dimorphism 4) Elaboration of material culture 5) Significant increase in brain size/body size 6)Long developmental period and long lifespan

Suspensory Locomotion & Vertical Climbing

1) Increased mobility of extremities 2) Shoulder blade located on back 3) Shoulder joint more open and loose for increased mobility 4) Forelimbs elongated compared to hindlimbs 5) Long and curved fingers for grasping branches 6) Fewer lumbar vertebrae

Females can improve likelihood of their & their offspring's survival in 2 ways

1) Invest more care & energy into offspring depends largely on her ability to obtain important resources (FOOD, nest sites, helpers) to support herself and her offspring. Probably the most important 2) Be choosy about males fathering offspring only mate with quality males

Robust Australopithecus (Paranthropus)

1) The robust group appears to have been an evolutionary dead end 2) they show a suite of craniotomy-dental adaptions for producing high bite forces 3) species include the East African Au. (P) aethiopicus, Au (P) Boise and South African Au. (P) robustus

adaptive explanations for the origin of bipedalism

1) carrying tools, food, or infants 2) ecological influences: (traveling between trees or seeing over tall grass) 3) preadaption from a change in feeding postures 4) provisioning family 5) energy efficiency

two major benefits of sociality (through this is not an exhaustive list) are

1) enhanced access to resources 2) reduced vulnerability to predation or likely some combination of these factors

Au. africanus (3.5<2.0 mya)

1) more derived than Au. afarensis, this hominid may have a unique relationship to Au. robustrus or Homo 2) Derived characters include a rounded vault (absence of cranial cresting), a somewhat flexed cranial base, and a more parabolic dental aracade 3) the post cranial skeleton is similar to Au. afarensis

Au. afarensis (3.9-2.9 mya)

1) more derived than Au. anamensis; may be ancestral to later Australopithecus 2) primitive cranial characters include cranial cresting (compound temporonuchal and sagittal); a prognathic face; a shallow, U shaped; and large anterior teeth 3) derived characters include somewhat smaller canine crown and root, somewhat smaller anterior dentition and slightly enlargement of the posterior dentition 4) the post cranium is that of a biped, with some primitive retentions such as curved phalanges, a wide pelvis, short hind limb, long forelimb, and funnel-shaped thorax

behavioral traits of primates

1) most primates live in day 2) sociality- group living- one fundamental social adaption of most primates

Au. sediba (1.97-1.78 mya)

1) small bodied and brained (around 420cc), this species had long arms 2) a broad brain case and derived face, and some changes to the pelvis are argued to be like Homo 3) It discovered argue that this species may have a unique relationship to Homo or even H. Erectus

Au. anamensis (4.2-3.9 mya)

1) this early form is likely ancestral to Au. afarensis 2) primitive characteristics include a shallow, U-shaped palate and large anterior teeth 3) derived characters include somewhat canine crown, thick enamel, and adaptions to bipedalism

knee

1) valgus angle of the knee 2) deep patellar groove 3) enlarged articulation between the femur and tibia

vertebral column

1)Cervical (neck) and lumbar (lower back) curvatures to maintain center of gravity over the pelvis, 2) Increased height of the lumbar vertebrae to support body weight

how to become a fossil

1. Have hard (mineralized) skeleton or shell 2. Die 3. Die in a good place for burial (cave, stream margin, volcanic landscape) 4. Get buried (protects body from ravaging by carnivores, weather) 5. Get buried in a good place for preservation - dry, not too acidic 6. Avoid subsequent disturbance

ways to fulfill energy needed

1. Lots of low quality food (Larger animals) 2. Less high quality food (Smaller animals)

isotopic/radiometric methods

14C-dating, K-Ar dating, Uranium series dating

oxygen isotopes

18O/16O (In seawater, more 18O in cold periods when "light" water evaporates and is tied up in snow and ice, sea levels go down)

early apes appear when

23 million to 16 million (in Africa and Asia)

When do Platyrrhines originate?

25 to 30 million years ago (when South American is an island)

when do the earliest potential hominins appear

5 to 7 million years ago

When did humans and chimpanzees share a last common ancestor?

6 million years ago

when did primates originate?

63 millions years ago

what in primate environments do you think may have been selected for the ability to see red colors?

>>Trichromatic vision can be very valuable addition when you specialize on ripe fruit; also makes it easier to see red-orange fruits against a green leafy background. >>May also help distinguish between young and mature leaves. >> Species, recognition Communication through facial signaling E.g., guenons - highly diverse, overlap in their distribution

what kind of body plan do primates have?

A generalized body plan. (There is no special morphological forms that diversify one primate from another. This general body plan allows for versatile ways of living.)

Dominance relationships between pairs of individuals (or dyads) often form a LINEAR dominance hierarchy

A is dominant to all individuals, B is dominant to all individuals but A, C is dominant to all individuals but A and B, and so on But sometimes, dominance relationships are not so clear-cut, and individuals may COOPERATE with other individuals to supplant others who are individually dominant to them.

fission-fusion system

A social group of multiple individuals sleep all together, but when foraging for food, break up into pairs or smaller groups during the day. (Form of mating system in which there are temporary subgroups but no stable, cohesive groups. Examples: bonobos and chimps)

instantaneous or scan sampling

Activities recorded at pre-selected intervals, Group or individual based (An animal's activities are recorded at pre-selected moments (e.g., every 30 seconds). It is a sample of states (you are unlikely to catch an animal "in the act" of doing a behavior classified as an event), and is used to study the percent of time spent in a certain activity. If the behaviors of all members of a group are surveyed within a short period of time, we call it scan sampling. This provides data on the distribution of behavioral states in a group. Instantaneous or scan sampling is best done with a sample interval as short as possible, and with behaviors that are very easily identified. The behaviors should ideally be relatively long compared to the sample interval. It is an excellent method for collecting a large amount of data on a group of animals)

17-15 Ma

Africa and Arabia collide with Eurasia Land bridge to Europe, Asia, closure of Tethys Sea Spread of apes and eventually monkeys out of Africa Rise of mountain barriers due to collision

Behavioral responses to predation

Alarm Calls, Mobbing, Avoidance, Polyspecific (multi-species) associations

Defense against predators

Alarm calls (depending on predator), Fleeing/avoidance, Mobbing (the predator)

mammary glands

All mammals possess MAMMARY GLANDS, which produce milk to nourish their young.

Animal prey such as insects provides a good source of fats and oils

Although seeds are a good source of vitamins, fats, and oils, many plants package their seeds in hard husks or pods to shield their contents from seed predators. Primates get most of their protein from insect prey and from young leaves

prosimian vs anthropoid classification

Anatomically based (Prosimians: Lemurs, Lorises, Galagoes, and Tarsiers. Anthropoids: OWM, NWM, Apes, and humans.)

Dead End in Ape Evolution: The Oreopithecids

Another branch of apes, orepithecids, are believed to be an evolutionary dead end.

Anthropoid Origins: The Fayum

Anthropoids = Haplorrhines minus the tarsiers

Hominoids include

Apes: (Gibbons, Orangutans, Gorillas, Chimpanzees, and Bonobos) Humans

apes vs monkeys

Apes: thorax is broad from side-to-side, not deep, No tail, Larger body size, Long arms and shorter legs Monkeys: deep thorax, not broad, Tail

In fact, there are also some new areas in the neocortex of the brain that are specialized for processing of visual information

Areas involved in visually-guided reaching, recognizing the identity of individual faces, and recognizing different facial expressions

Quadrupedal morphology

Arms and legs are about the same length, Long, flexible lumbar spine, Usually have a TAIL for balance. (Deep, not broad, thorax, Scapula located laterally, Foramen magnum placed posteriorly, near rear of cranium.)

fitness

As we know from our understanding of natural selection, the environment places pressure on individual organisms. Because of variation in traits, it is inevitable that some individuals are better suited to survive than others. These individuals will pass their genes along to the next generation. These individuals are "fit". So, how does this happen?

Lesser known species between 2.5 and 3.5 mya are

Au. bahrelghazali, Au. garhi, Au. deyiremeda, K. platyops

cercopithecines

Baboons, macaques, guenons, mangabeys, patas monkeys. Cheek pouches for food storage, some females go into "estrus" (period of sexual receptivity marked by ano-genital swelling). Sexual dimorphism more pronounced han in colobines

early-middle Pleistocene

Brunhes/Matuyama boundary 788 kya

Again, the efficiency of bipedalism is also relevant to these arguments. Some of the problems that have been raised concerning this hypothesis include the fact that other primates are known to take a bipedal stance when watching for predators, or use a bipedal feeding posture - chimps do this quite a bit.

But again, this doesn't preclude the possibility that the opening up of environments at the end of the Miocene, including grasslands, would have provided the context and a set of conditions in which human bipedalism could have evolved, allowing humans to spread out into new habitats on the African landscape.

when did primate evolution occur

Cenozoic era (the past 65 million years)

Enamel thickness

Chimpanzees have thin enamel, while modern humans have thick enamel

In fact, half of the neocortex in most primates is visual in function

Chris Kirk study of relative optic canal size and relative brain size... so amazing, that so much of the primate encephalization reflects an increase in just raw visual input

Climate Shifts and Habitat Changes

Climate changes occurred during this time in Europe, Aftica, and Asia, resulting in the disappearance of fruit resources commonly exploited by the apes.

male cooperation has very tangible benefits

Coalitions- (cooperation in an aggressive or competitive context such that the interests of the cooperating parties are served at the expense of the third party) Mate guarding Hunting Territory defense

Dentition

Consists of incisors, canines, pre-molars, and molars. (Cusps of molars can either have Y-5 (hominoids) or bilophodont (leaf eaters/Old World Monkeys) cusps.)

What was the locomotor strategy of the last common ancestor that humans shared with African apes?

Did this LCA knuckle walk, in a manner similar to chimpanzees and gorillas today? Or, was this LCA primarily arboreal, an arboreal quadruped most likely? > If this was the case, it would have required that knuckle-walking evolved independently - evolved twice - in both gorillas and chimpanzees. Researchers are split on the answer to this question, although many point to anatomical evidence conferring increased stability in the wrist joints of early hominins to support the notion that they too were adapted for knuckle walking. The discoverers of Ardipithecus argue that this fossil taxon provides some new insight into this question, as we will see.

Asian forms: Sivapithecus Middle - Late Miocene: 12-8 million years ago (ma)

Differentiated from African lineage of apes after 15 mya Many features of the skull suggest a close evolutionary relationship between Sivapithecus and orangutans. Postcranium suggests quadrupedal locomotion.

when do primitive anthropoids first appear ?

Eocene to the Oligocene epoch

problems of group living: does not account for the trade off between intra and inter group competition over access to resources. aggressive encounters between individuals of the same group increase as group size increases

Evidence: in brown capuchins in Peru, Charles Janson found that the largest groups had the highest rates of within group aggression, and that an individual's access to food was strongly influenced by the rate of aggression it received from other group members. Energy intake among group members varied by 37%. By contrast, intergroup competition was limited to relatively brief encounters over access to fruiting fig trees. Energy intake varied only by 3% between groups that were most and least successful in intergroup competition.

earth movements (earthquakes

Faults, Uplift - exposes older layers to erosion, Creates new topographies - where water and sediments can accumulate

primate females always provide extensive care for their young

Female primates are usually the primary (if not excl.) caregivers. This in large part reflects the fact that, since offspring depend on their mothers for nourishment during pregnancy and after birth, females cannot abandon their young without greatly reducing the offspring's chances of survival.

If females are clumped together in groups, then the cost of finding mates is likely to be low.

Females occur in clumped distributions when the foods they eat are found in clumped distributions Under these conditions, males are expected to focus on attempting to obtain matings with multiple females, rather than investing in establishing a long-term relationship with just one female and their offspring

MOST MAMMALS GIVE BIRTH TO LIVE YOUNG, AFTER A PERIOD OF GESTATION

Females support the embryonic and fetal development of their young inside the uterus. (GESTATION refers to that period of development between conception and birth, which takes place in the mother's uterus. Monotremes do not give birth to live young, but rather lay eggs. The eggs are retained inside the mother's body for a brief period, before released through the cloaca. Monotremes do lactate, but they release milk through openings in their skin. Do not have nipples.)

Early African forms: Morotopithecus > 20 million years ago (ma)

First evidence for broad chest and mobile shoulder, suggesting suspensory locomotion.

Eocene (55 - 34 MYA): The First Primates of "Modern Aspect"

First true primates (euprimates) in Eocene epoch, as early as 55 mya (ii. Clear primate traits, including postorbital bar, large brain relative to body size iii. Adapids and omomyids)

The distribution of food effects competition dispersed=scramble competition

Food is distributed evenly Not worth fighting over No direct competition

Since it takes so long to produce an infant, each female can rear a relatively small number of surviving infants during her lifetime

For example, a female chimpanzee who gives birth for the first time when she is 15 yrs old and survives to the age of 35 would produce 5 infants - and oftentimes not even this many infants will be born. Among human females, most produce not much more than 15 offspring in naturally conceptive societies. There are strong physiologic constraints operating on the number of offspring any single female can produce

competition for food is especially important to females!

For example, at Gombe, female chimpanzees some have access to better feeding resources within the community, and occupy smaller, yet more nutrient dense core areas. These females weigh more, have shorter interbirth intervals, and their daughters reach sexual maturity at a faster rate. In this case, the intake of valuable food items is directly related to gains in fitness.

evidence for larger groups generally being more successful in intergroup encounters than smaller groups

For example, in a long-term study of vervet monkeys occupying adjacent territories in Amboseli Park in Kenya, researchers (Cheney and Seyfarth) found that small groups suffered more incursions into their ranges and defended their ranges more aggressively than did larger groups, meaning that members of smaller groups incurred greater costs in territorial defense

Foramen magnum position

Foramen magnum is positioned completely underneath the skull in humans

primates seem to adjust their behavior in response to the risk of predation

Forest monkeys (guenons) give different alarm calls when they are alerted to the presence of leopards, small carnivores, eagles, snakes, baboons, and strange humans. The example of chimpanzee predation on colobus monkeys, where adult red colobus monkeys aggressively attack chimpanzees who hunt their infants. Suggests that PREDATION itself has been an important selective influence on primate evolution.

rock shelter site formation

Freeze/Thaw is a big factor in colder climates, Generates debris or eboulis, Stratigraphy can be complex, In tropical climates primary mode of sedimentation is aeolian

anatomical traits of primates

Fundamental primate adaptation- some strepsirhines don't exhibit this trait. Unlike other mammals, 5 digits per hand and foot. Grasping with greater precision. Five fingers are a shared ancestral (or primitive) trait of all primates

Anthropoid features

Fused mandibular synthesis Full postorbital closure Fused metopic suture

Ancestral anthropoid features

Fused mandibular synthesis Full postorbital closure Fused metopic suture Longer snout and relatively smaller brain compared to OW monkeys and apes

what is the difference between a strepsihine and a haplorhine?

Genetically based. Strepsirhines: lemurs, lorises, galagoes. Haplorhines: Tasiers, NWM, OWM, Apes, and Humans.

primate life history traits

Growth and Development of Primates In general, primates live relatively slow lives compared to many other mammals. Most primates give birth to only one offspring at a time (but twins in callitrichids) And they do this after a long gestation compared to other mammals. Primates are characterized by a prolonged period of growth and development, and delayed maturation Primates also have long lifespans

Carbohydrates are obtained mainly from the simple sugars in fruit

Gum, a substance that plants produce in response to physical injury, is also an important source of carbohydrates from some primates, particularly galagos (Streps), marmosets and tamarins (NWMs)

radioactive decay

Half life, Logarithmic, (6-7 half-lives approach limits of detection (<1% of original amount of radioactive material remains))

DOMINANCE

Has been defined in many different ways in primates, but most commonly measured in terms of the direction of approach-retreat interactions, or the direction of submissive and aggressive behaviors in interactions When these interactions define winners and losers, when it comes to access to resources, the outcome of these interactions is often highly consistent over time. WINNER = Dominant individual LOSER = subordinate

nocturnal primates predation strategies

Hide during day, Park infants while foraging, Solitary, Quiet, Cryptic

contest competition produces dominance

Hierarchies form after repeat aggressive encounters between individuals

territory

Home ranges that are defended against other members of the same species. (Critical resources are usually located in these defended portions of the home range.)

Energetic efficiency. The idea that walking bipedally in the manner that modern humans do consumes less energy than walking quadrupedally, or than knuckle walking like the modern great apes.

How the muscles contract from the hips down to the toes has a lot to do with the efficiency of moving on 2 legs. Measuring the amount of oxygen consumed is one way to calculate this. Experimental studies have shown that bipedal walking is more energy efficient over long distances than walking on 4 legs Modern human walking is potentially as much as 40-50% more efficient than the quadrupedal walking of a chimpanzee It is true that there are a lot of quadrupeds in the world that do just fine. But, any small change that could have improved the efficiency of walking on two legs might well have increased the range over which our ancestors could search for food.

Between 7-4.4 million years ago, we have evidence in the fossil record of a small number of CANDIDATE SPECIES - species that are proposed to be hominins and therefore represent the earliest part of the human lineage.

However, given the fragmentary nature of these remains and their mix of traits, their precise evolutionary relationships are unclear. If not hominins, one or more of these species with more evidence may turn out to be an evolutionary side branch close to the base of the hominin evolutionary tree

Group living incurs costs such as intra, or within group competition for resources and vulnerability to infectious disease as anyone who got the flu this year can attest.

However, given the prevalence of sociality among primates (and other taxa as well including cetaceans) there must be benefits that outweigh these costs.

all primates can see in three-dimensions: stereoscopic vision

IF we think about most other mammals, such as horses, the eyes are positioned on either side of the head. This allows for a field of view that extends nearly 360 degrees, with a blind spot in a rear. This is advantageous in many ways, namely detecting predators at a distance. However, forward vision is not very good, because the fields of view coming in from the eyes don't overlap very much up front.

New functional area in the frontal lobe in primates, the ventral premotor cortex (right around the side of your eye sockets), is involved in visually-guided reaching

If electrically stimulated in macaques, the primate reaches forward and brings its hand up to its mouth

Heat stress can be a significant problem in an open, sun-baked savanna, more so than in the shade of the forest

If humans evolved bipedalism in an open savanna environment, as it was originally thought, an erect bipedal posture may help to reduce the proportion of the body directly subjected to solar radiation This would then reduce heat stress, and lessen the amount of water loss in sweating needed to keep the body cool BUT, we now know that the earliest bipeds at least had access to more closed wooded environments, without the pressure of heat stress, so this probably was less important as a factor.

primate ecology

Important to view primates as members of an ecosystem. The environment is a template on which natural selection molds behavior. At the same time, primates influence ecology, as seed dispersers or pollinators. Primate behavior evolved in direct response to environmental pressures, so it is necessary to understand these factors.

compared to other mammals, the primate brain is large relative to body size

In fact, at all stages of gestation, the brain constitutes a larger proportion of body weight in primates compared to other mammals

The behavior of fathers is much more variable

In many primate species, fathers give little more to their offspring other than the genes contained in their sperm In a minority of species, males are devoted fathers and contribute significant offspring care (Callitrichids) Siamangs, owl monkeys - males can help females by defending territories or by carrying infants so that the mother can feed more efficiently Or, they may contribute in more subtle ways, such as providing protection in aggressive encounters. However, males are never capable of rearing their offspring ENTIRELY without help from females

postorbital bar and closure in primates

In some primates (i.e., anthropoids), the space that contains that eye is further separated by a bony postorbital plate, situated behind the eyeball. This isolates the eye entirely from the chewing muscles that lie behind it, and forms a bony socket in which the eye is located. The functional significance of the postorbital bar and postorbital plate is contentiously debated. However, it may relate to the increased importance of vision in primates, and function in isolating the orbital contents from the effects of chewing muscles.

If females are sparsely dispersed in the environment, HOWEVER, then it may be difficult and time-consuming for males to locate prospective mates

In such cases, males may benefit more from establishing a pair-bond with a single female and investing in their offspring, rather than seeking matings with many different females OR, he may cooperate with other males to form multi=male groups.

More indication of the unique visual specializations in primates.

In the primate brain, what we see is more segregation of function - one of the things you get with a bigger neocortex is greater capacity to have these specialized regions.

Prototheria

Includes only the Australian platypus and echidna. Reproduce through egg laying.

group better access to resources

Increased foraging efficiency, Transmission of socially learned foraging behaviors

kin selection

Individuals favor/help related individuals, thereby increasing inclusive fitness

sexual density hypothesis

Infanticide is a male reproductive tactic Mother returns to estrous Females conceive earlier Reduces competition from other males (Infanticide is a male reproductive tactic: 1) Loss of suckling infant leads to the onset of estrous in the mother 2) Males gain a reproductive advantage through earlier conception by females. But what happens when it's committed by females? A female named Passion began killing and eating several of the babies in her community. Together with her daughter Pom, over a period of many years they attacked and killed infants in their group. Usually when males kill a baby, they don't eat it, but these females seemed to be after meat; they'd chase and consume the infant. They were actually seen to eat 3, chase 3 others, and there were 8 others who disappeared under mysterious circumstances. In this period, there were almost no infants weaned successfully. So this is kind of a question mark because it's only been these two individuals documented- and the daughter probably learned it from the mom- so maybe we can label this one pathological and say that it's not a part of normal chimp behavior.)

most living primates show one of three different basic kinds of dietary adaptions

Insectivores (insect eating) Folivorous (leaf eating) Frugivorous (fruit eating)

Fruit often meets these three requirements

It is valuable because it is high in carbohydrates that can quickly be converted into energy to fuel the body's metabolic needs Fruit grows in discrete patches on trees, bushes, and vines Many fruiting species produce large enough crops to feed several individuals at the same time

However, contests among males can be more violent than those among females, because there is more at stake!

It's an all or nothing game for males. Males can't share fertilizations like females can share food. - either you fertilize or you don't! Male competitive ability is an important determinant of RS!

for males, the main limiting resource is the availability of fertile FEMALES

It's an oversimplification, right - males still have to eat! However, food isn't as limiting for them as it is for females, because they only have to feed themselves. Rather, the availability of females appears to have a more significant influence on variation in male strategies. >> So, the social strategies - and as we'll see, the life history strategies - of males is ultimately influenced at least in part by the temporal and spatial distribution of fertile females.

Canine size and sexual dimorphism

Large male canines and body size dimorphism signal male-male competition for females - most intense in one-male, multi-female groups

Hominoid characteristics

Larger body size, No tail, Catarrhine nose, 2.1.2.3 Dentition, Increased encephalization (i.e. brain size and intelligence), Extended life histories (ontogeny), Social complexity

Adapoids

Larger in body size Elongated snout Many were diurnal Larger species - folivory and frugivory Quadrupedalism; many were cautious quadrupedal climbers

Derived hominoid features

Larger relative brain size Shorter snout compared to Aegyptopithecus Y-5 molars Lacked a tail

Difference between leaves and fruit from a tree's POV

Leaves are required for the tree to grow (photosynthesis), (so a tree should be naturally selected to have mechanisms to defend its leaves from leaf-eaters. Trees don't want their leaves eaten.) Fruit hold the seeds that have the reproductive oppportunities for trees. (Trees want their fruit to be eaten.)

Strepsirhines include

Lemurs (madagascar), lorises, galagoes (mainland africa and tropical asia)

lemurs

Lemurs found only on madagascar. Includes families lemuridae (true lemurs), Cheirogaleidae (dwarf lemurs), Indriidae (sifakas and indri), and Daubentoniidae (aye-ayes). Madagascar broke away from continental africa approximately 100 million years ago, and the primates on the new island began to evolve without gene flow. Most researchers believe that all lemurs come from a single origin of madagascar primates. Currently, however, most lemurs are incredibly endangered due to extreme deforestation in Madagascar.

relative methods

Lithostratigraphy, Biostratigraphy, Geomagnetic polarity

VCL (vertical clinging and leaping) morphology

Long legs compared to arm size, Vertical body posture, Small to medium body size, Most strepsirhines.

Brachiation morphology

Long upper limbs, including the fingers, No tail, (A monkey in a tree with a prehensile tail would be considered a quadruped with a prehensile tail.) Large body size, Short, stable lumbar spine, Broad thorax, not deep.

bipedalism morphology

Longer legs, Cranium balanced on erect trunk, Broad thorax, Big toe in line with other toes (nondivergent toe).

avoidance example

Longtailed macaque groups (will go up into trees at night to sleep, and they repeatedly use the same trees for sleeping. However, if they encounter a python in a tree they're unlikely to use it ever again. The interesting thing is, they don't show the same response in feeding trees; they'll go back and eat at a tree even if they saw a python there before. They do alter their behavior while eating, however; they stay closer to other individuals after having seen a python.The difference probably is that they feed in daytime so they can see better, so they're a little more secure. )

Derived catarrhine (OW anthropoid) features

Loss of the 2nd premolar, giving it a dental formula of 2.1.2.3

problems of the early hominin record (6ma-30ka)

Major gaps/discontinuities create apparent "revolutions" Assemblages/geological surfaces represent time-averaging of unknown duration --- on order of 100, 1000 or 10,000 years

gorilla

Males reach sexual maturity in their mid teens, becoming "silverbacks". Younger males with dark fur are "blackbacks". Females give birth about every 4 years

primatology

Many behavioral studies focus on sociality, the most fundamental primate behavioral adaptation (methods of data collection standardized in 1974 by Jeanne Altmann)

like the resource defense model, the predation model also has some weaknesses. most notably, it is difficult to directly observe predation because

Many predatory species avoid close contact with humans, or they hunt at night (leopards) Usually, predation is inferred when a healthy animal, who is unlikely to have left the group, abruptly disappears; Since it is difficult to directly observe predation, it is difficult to establish whether predation is clearly linked to group size

Metatheria

Marsupials. Reproduce without placenta, but rather, pouches. (Example: kangaroos)

European: Dryopithecus

Middle - Late Miocene: 15-10 million years ago (ma)

complete animals are rare

Most fossils are fragments - especially of teeth (Tooth enamel is 99% mineral already, Dentin is ca. 70% Can reconstruct type of animal, size, diet even social organization from teeth alone)

dietary and digestive strategies

Most species have evolved dietary or digestive specializations that allow them to coexist with other species by carving out their own ecological niches. For example, to eat leaves, colobines have semichambered stomachs with a clear foregut that allow them to digest the secondary compounds that are toxic or otherwise indigestible. Additionally, primate body size is determined in large part by feeding strategies such that small individuals can eat a little of a high energy food, while large bodied individuals must eat a lot of a low quality food.

anatomical traits of primates: flattened nails

Nails instead of claws. Only two group of primates retains claws (marmosets and tamarins, as well as aye ayes) who secondarily evolved claws from their nail structures.

Early hominin fossil localities are primarily from east and south Africa, spanning a broad region that runs north to south from the Horn of Africa at the Red Sea, southwards towards the Cape of Good Hope.

Nearly all fossil evidence from the first 4 million years of human evolution (7-3ma) comes from East Africa, from a region known as the Great Rift Valley.

altricial

Nearly all primates give birth to offspring one at a time, as opposed to other mammals who experience large litters. Single births, paired with the extended gestation rate and long periods of maturation, makes primates "invested parents" compared to other mammals. For the most part, primates are what you call K-selected species. expend high cost in reproduction for a low number of more difficult to produce offspring.

Haplorhine traits that differ from Strephsirhines

No tapetum in eyes, Color vision, Diurnal, Larger brains, Larger body size, Social groups with extended parental care

bonobo vs chimpanzee

Often painted as the 2 faces of "human nature". Neophilic vs. neophobic Strong female bonds and authority vs limited female bonds Playful vs aggressive

Classified into two families

Omomyidae more tarsier-like Adapidae more lemur-like

lemurs

Only found in Madagascar. (True-lemur: Ring-tailed lemur. Dwarf lemur: Greater dwarf lemur, Aye-aye, Sifaka)

thermometers -climate

Oxygen isotopes Soil features (cold - solifluxion, cryoturbation -- or hot - aridification, laterites) Sea level changes Fossil pollen (palynology) Palaeontology (especially micropalaeontology - micromammals, snails, slugs, birds, molluscs, diatoms, ostracods etc.)

scales

Palaeontology/ Biostratigraphy, Sedimentation rates, Palaeomagnetism, Fluorine

Primates in the Paleocene?

Paleocene fossils a possible candidate for the early primate ancestor Plesiadapiforms

fruit properties

Patchy distribution and seasonal. (Brightly colored, pleasantly smelling, soft texture: attractive to primates.) More nutritious than leaves: (high levels of carbohydrates in form of sugars.)

Most mammals - known as eutherian mammals - possess a PLACENTA that nourishes the fetus during gestation using the mother's blood supply.

Placenta allows for more efficient exchange of maternal nutrients reaching the fetus, and therefore a longer gestation period. So, as a result of their long gestation times and placental nourishment, the young of placental mammals are relatively well developed at birth.

Eutheria

Placental mammals. Reproduce through internal fertilization. Includes primates.

Leaf properties

Plentiful and evenly distributed. Poor sources of nutrients and calories compared to fruits. (Difficult to digest due to protection mechanisms (bristles, spines, or hairs). Young leaves contain minimum fiber and are more nutritious. Older leaves contain much fiber and are tougher, Fiber inhibits digestion.

First fossil primates to have

Postorbital bar Grasping hands and feet (opposable big toe) with nails instead of claws Relatively larger brains Shorter snout, eyes in front

predation of primates

Predators are usually nocturnal and solitary. (Types of predators: snakes, crocodiles, raptors, carnivores, and chimpanzees prey on red colobus.)

extended ontogeny "life cycle"

Primates have long lifespans with extended life stages. In particular, the infant and juvenile periods of primates, particularly great apes, are incredibly long compared to those of other mammals. Many hypotheses exist to explain the extended period of juvenescence in these species, and often they stress the importance of "learned behavior". Long lived primates have a variety of things to learn about their environments, from feeding strategies to social behavior, so this lengthened period of time may allow young animals time to understand their world while still under mom's protection. Additionally, most primates are born in what we consider "Altricial" state. This means that they are incredibly reliant on mom due to their limited development (limited locomotion, brain not fully developed, etc.). In contrast with "precocial" species, like deer.

Different types of food require different types of dental preparation before swallowing

Primates that specialize on fruit use their incisors to tear off small pieces that can then be properly chewed by the premolars and molars. (Think about when you are biting into an apple, or even biting off a piece of banana.) They tend to have relatively large incisors, compared to folivorous primates. Smaller food objects, such as seeds, as well as grasses and leafy vegetation, are usually passed directly back to the chewing teeth. Primates that specialize in these kinds of foods usually have smaller incisors than do fruit eaters.

benefits of living in a group

Protection against predators, Better access to potential resources, Access to mates

Brachiation

Purely arm swinging, (Supports the body using the forelimbs to hang beneath a tree branch) (Swinging from tree limb to tree limb)

Primates vary in locomotive patterns. What are these different types of locomotive patterns?

Quadrupedalism, Bipedalism (Only humans use this), Vertical clinging and leaping (VCL), Brachiation (Suspension in lab)

Difference between quadrupeds and VCLers?

Quadrupeds use all four limbs to support themselves in the trees or on the ground. (e.g. knuckle-walkers) VCL'ers use mainly their hind limbs to support themselves, though they do use their arms to grasp to trunks of trees.

All non-human primates are what types of locomotor?

Quadrupeds. (However, some primates may use VCL locomotion or a quadruped running through the trees or the ground.)

clocks

Radiometric (best) - (depend on atomic decay) Luminescence/ trapped charge - (depend on regular absorption of atomic energy from soils into crystalline materials) Biological - (annual rings or layers (trees, varves) OR protein diagenesis or decay - amino acid racemization)

Basal Metabolic Rate (BMR)

Rate of energy consumption required to maintain life when animal is at complete rest. (Energy beyond BMR is used for everything and anything besides resting. BMR = 70*(weight)0.75 kcal/kg/day)

Given this physiologic constraint on reproductive capacity, females are extremely limited in their ability to increase reproductive success by increasing the # of offspring

Rather, the best option females have to increase their RS is by increasing chances of survival of those offspring

simple view

Resources are distributed throughout the environment, either even or patchy distributions, females follow the food, males follow the females

Purgatorius

Rodent-like size and shape BUT 3.1.4.3 dental formula - could be ancestral to later primates Less -specialized molars - frugivore?

Fossils from North America, Europe, Asia

S. America and Africa separated from N. America/Eurasia by seas

What species might be the earliest hominins and what does their anatomy and environment tell us about the selective pressures that might have facilitated their evolution?

S. tchadensis (pg 251) Their anatomy and environment tells us that they were found in West Africa in a very dry, lightly forested area near a lakeshore in the late Miocene

INSECTS AND OTHER PREY animals occur at even lower densities than either leaves or fruit.

Since food supplies for folivorous species are generally more uniform and predictable in space and time, they generally have smaller home ranges than frugivores or insectivores.

New world monkey characteristics

Small body size, ALL have tails; (some have prehensile tails), Platyrrhine nose: (broad and flat with widely spaced nostrils), Three premolar teeth, Dental formula: 2 1 3 3, ALL Arboreal, ALL Diurnal (except Owl Monkey), Omnivores: (eat fruits, seeds, leaves, gums, and insects)

Strepsirhines characteristics

Small body size, Long snouts, Claws on one pedal digit, Large ears, Rhinarium (wet, naked surface around nostrils of the nose in mammals), Tooth comb, unfused mandible, Arboreal, Nocturnal, Solitary

So, both hemispheres of the brain each receive visual information (and parallax) from both right and left eyes. In all primates, about 40% of optic nerve fibers remain on the same side of the brain.

So, anatomical changes in the primate brain have accompanied and provided the circuitry required for enhanced depth perception, lending primates the unique ability to interpret overlapping fields of view from each eye as a 3D image. Primate brains are the only ones that do this.

cost of group living

Social Management, Competition, Contagion, Cuckoldry, Inbreeding, Infanticide

primates are variable

Some NWMs, and all Old World monkeys, apes, and humans have evolved Trichromatic vision.(RIGHT) They have three different opsins, which allows them to discriminate between blues, reds and greens

bias in the fossil record

Some environments promote fossilization more than others. (Politics and other factors may also intervene Some skeletal parts preserve better than others Bones, shells, and especially teeth) (The fossil record is not a complete record of the history of organisms ever to exist on earth; it is only a sample of the plants and animals that once lived.)

FRUITS are rich in carbohydrates and calories, but they are temporary tree products- they ripen and rot quickly and are much more ephemeral and less predictable than leaves.

Some fruits are seasonal, but others have unpredictable fruiting cycles. Fruit can also be unevenly distributed in a given tree. Primates who eat fruit must be able to efficiently locate fruit by having knowledge of their habitat. Additionally, once found they must be able to compete for access to this resource.

The lake margins provided likely habitats for early hominins This has been an extremely productive region in terms of yielding fossils (from the late Miocene to more recent).

Some of these sediments were subsequently uplifted by rift tectonics and are now eroding. Because the rapidly eroding highlands have filled the valley with sediments, a favorable environment for the preservation of remains has been created. Further, the volcanoes have spewed numerous ash layers across this landscape throughout their history. These ash layers can be easily identified, and dated using chronometric dating techniques. Therefore, not only has this region been productive in terms of yielding fossils, but most of these fossil sites have been well dated.

Paleocene (65-55 MYA) Plesiadapiformes

Some plesiadapiformes possessed some, but not all, derived primate traits: Petrosal bulla, Grasping big toe, Nail on at least one digit

Bipedalism may have emerged to free the hands for carrying various objects - whether it be tools, infants, or food.

Some problems here: Chimpanzees are known to use tools, but they have not evolved bipedalism. Also, more complicated stone tool technologies don't show up in the fossil record until several million years later. So, this probably wasn't the main trigger. Lovejoy has proposed an elaborate model, which ties the evolution of bipedalism to a dramatic change in life history and the evolution of monogamy in early hominins; In which bipedalism evolved to allow males to carry back foods, to provision small families consisting of a mated female and her offspring. We'll talk about this more later.

strepsirhines

Strepsirhines include lemurs of madagascar and lorises and galagos of mainland africa and tropical asia. Strepsirhines rely heavily on olfaction, they are often nocturnal, and many lack complex social behavior patterns. Strepsirhines have what is called a tooth comb, or a protrusion of the bottom incisors, that is often utilized for grooming. Many also have clawed toes thought to be useful for grooming, and with the exception of many lemur species, many strepsirhines are solitary or pair living

Nicholas Steno (1638-1686)

Studied shark teeth in old marine sediments, Led to laws of superposition, horizontality, lateral continuity

Haplorhines include

Tarsiers, New World Monkeys (Ceboids), Old World Monkeys (Cercopithoids), Apes and Humans (Hominoids)

chronometric dating methods (clocks)

Techniques that estimate the age of a fossil in years, through the use of a natural 'clock' such as radioactive decay, or regular absorption of radiation energy from the sediment (Isotopes are variations of the same element, which differ in their molecular weight.)

anatomical traits of primates: generalized teeth

Teeth are lacking in specified adaptations (ie. Exaggerated canines for tearing meat or heavy grinding molars for shearing plant materials)

philopatry

The act of remaining in one's natal community

diets influence ranging patterns

The challenge of finding preferred foods in tropical forests influences how they use the landscape and how they organize themselves into groups.

Apes Return to Africa?

The fossil record for the late Miocene is too fragmentary to shed light on the question of whether early hominids descended from Miocene ancestry in Europe or Africa.

what conditions favor fossilization?

The organism generally must have hard parts such as shell, bone, teeth, or wood tissue; the remains must escape destruction after death; and the remains must be buried rapidly to stop decomposition. This does make the fossil record biased because animals with soft bodies are less likely to form fossils. It also means that particular environments will not help fossils form because the remains must be buried rapidly and escape the detection of scavengers.

Early Anthropoids Evolve and Thrive

The origins of catarrhines are clear: Aegyptopithecus. The origins of the platyrrhines are less clear. The first South American primate is Branisella, from Boliva, dating to 26 mya.

Early African forms: Proconsul 24-18 million years ago (ma)

The postcranial skeleton indicates that Proconsul was quadrupedal, and lacked many of the derived features for suspensory locomotion seen in living apes.

what is a fossil

The preserved remains of once-living organisms (usually reserved for remains that have been 'lithified' = turned to stone)

anatomical traits of primates: generalized body plan

The primate body plan is not specialized. To think of specialization, consider the extremely long neck of a giraffe that is designed for exploiting foods that grow in tall trees. Primates do not have these types of specializations, and are instead highly variable. For example, primates have many styles of locomotion. Technically, all non-human primates are designed as quadrupeds (walk on all four legs), but different species use their limbs in different ways.

Home range

The spatial area used by a primate group. The area covered during normal movements and activities. (The range must contain all the resources needed by a nonhuman primate: water, food, shelter, and mates.)

ecology

The study of the interrelationships of animals, plants, and their physical environment. (The environment provides the template on which natural selection acts. If primate behavior was developed through environmental pressures, we can only understand this behavior through the context of the environment they evolved in.)

This is a region where three continental plates (Arabian, Nubian and Somalian parts of the African plate) are actually pulling apart from one another.

The tectonic activity at these plate boundaries has resulted in the creation of a series of active volcanoes and lakes (Lakes Turkana, Victoria, Tanganyika, Malawi).

bipedalism

The two hind limbs support the weight of the body at all times and is above a firm terrestrial support: the ground. (Only humans use bipedalism)

Quadrupedalism

The use of four limbs to support the body above the ground or a tree limb. (Quadrupeds can be either terrestrial (ground liver) or arboreal (tree liver))

The best strategy males have for increasing RS is to increase their number of mates.

The way they do this is through 'competition' with other males. Because females are a limited resource, being 'choosy' isn't the best option for males to increase RS in most species.

Electron Trap methods

Thermoluminescence, Optically-stimulated luminescence, Electron spin resonance

Baboon and other Cercopithecine males can have very aggressive fights, which often lead to physical injury

These usually occur during periods of rank instability, or among individuals occupying similar ranks . They often occur when new males either enter, or attempt to enter a group, or challenge a leader male. THESE KINDS OF FIGHTS AMONG MALES CAN BECOME FATAL - SUCH AS CHIMPANZEES (WHERE OFTEN MULTIPLE MALES WILL GANG UP ON A SINGLE MALE) AND GORILLAS.

LEAVES are everywhere in a tropical forest; and they tend to be more predictable in supply and available in larger densities than leave and insects

This doesn't mean they aren't still patchy in a spatial or temporal sense: Certain species may produce leaves only 7-8 months of the year, and/or prefer specific habitat characteristics. As we discussed earlier, as leaves mature they harden and may have higher toxins so many primates prefer young leaves. Despite these things, though, leaves tend to be more abundant and predictable in supply than other foods.

Because there is high variance in reproductive success among males

This imbalance leads to competition among males for access to females

expansion of the neocortex of the brain

This is a layered structure on the outside of the brain (like the rind of an orange), which is involved in more complicated higher-ordered processing of information and other functions such as sensory perception, generation of motor commands, spatial reasoning, and in humans, conscious thought and language.

Can also make generalizations about the species themselves based in their diet. In general, insectivores are smaller than frugivores, and frugivores are smaller than folivores

This is related to the fact that small animals have relatively high energy requirements for their body size than larger animals do, due to their fast metabolisms; they require relatively small amounts of high-quality foods that can be processed quickly. In contrast, large animals generally have slower metabolisms for their size. They don't need to process their food as quickly, but they do need food in high quantity. They can therefore feed on foods, such as leaves, which are available in large quantities but take longer to process.

Primate eyes lie in the front of the face (not the sides).

This means that our peripheral vision is not great, and we can't see behind us. BUT, because the visual fields seen by each eye overlap extensively, we have a broad overlapping field of view throughout most of our visual range = binocular vision (overlapping fields of view). Why might this be advantageous?

the volume of the neocortex is especially expanded in the primate brain

This region is involved in higher cognitive processes, such as processing visual information and using this information in spatial reasoning, memory, planning for the future, and in humans, language.

How successful a male is, however, is more related to access to females

Thus males distribute themselves in such a way to maximize opportunities to mate with females.

cycles of a tropical forest

Tropical forests are incredibly diverse and cycles are asynchronous. Different trees fruit at different times, making it necessary for primates to know their habitats intimately in order to find food.

ape teeth

U-shaped dental arcade, Large canines, broad incisors

Molecular evidence tells us that we should expect to find the earliest evidence of early hominins between 8-6 million years ago.

Unfortunately, the fossil record is poorly represented during this time interval.

anatomical traits of primates: forward facing eyes with stereoscopic vision

Unlike most mammals, primates have eyes at the front of the skull as opposed to the sides. Consider horse vs. human. Primates have stereoscopic vision, eyes facing forward w/ overlapping fields of vision give you excellent depth perception

pliocene-pleistocene

WAS end of Olduvai subchron within Matuyama chron (1.8 mya) - now at 2.4 mya, Matuyama/Gauss boundary

Competition within and between groups also has an influence on the nature of female relationships

When resources are patchily or clumped, and females compete directly with other females in the group for access to those resources (i.e., when there is CONTEST competition), clear dominance hierarchies are often established, and determine the priority of access to resources

paleomagnet time scale

When the earth's magnetic field reverses, the new direction is recorded in rocks and sediments forming at that time. (Geophysicists can take a rock sample, mark the current magnetic North on the sample, and then measure the rock's own magnetic direction)

Adaptive origins of bipedalism

Whichever scenario turns out to be supported, there must have been a selective advantage to bipedalism in the beginning. And there have been no shortage of hypotheses, concerning the possible survival advantage posed by hominins that could have habitually walked upright:

Ecological influences. Emphasizes the role of changing environments in the Miocene and expansion of more open habitats.

With more open habitats, homs would have needed to travel greater distances between trees, for important food sources. Bipedalism may have evolved first as a way of seeing over tall grasses on the African savanna, in order to detect predators. Or, alternatively, bipedalism may have first evolved as a feeding posture, allowing for the efficient harvesting of fruit from the upper branches of small trees that predominate in African woodlands

diet

With the exception of a few species, many primates show traits of frugivory or folivory. Frugivory = fruit, folivory = leaves. Leaves are the energy producers for trees, important for photosynthesis and keeping that tree alive. As a result, natural selection should favor trees who have protected leaves. Conversely, fruit contains seeds, the reproductive organs of the tree. The seeds need to be dispersed in order for the tree to reproduce. Therefore, natural selection should favor trees with fruiting agents that are attractive to primates and other animals. Evidence suggests that this is exactly what happened. Fruit is brightly colored and sweet smelling. Leaves are often coated with spines and bristles, and they are high in fiber which is incredibly difficult to digest. Why doesn't everyone just eat fruit? Seasonable and unpredictable, also patchily distributed. As we will discuss, the type of food you eat is highly indicative of feeding competition. Primates also consume animal protein which includes insects and smaller animals

Ape

Y-5 molar pattern

tephrostratigraphy

a form of lithostratigraphy in which the chemical fingerprint of a volcanic ash is used to correlate across regions

canine

a simple, pointed, curved tooth, usually larger than the other teeth- it serves many functions such as grasping, stabbing, ripping and tearing food; also a role in defense and dominance. in anthropoids, male canine tend to be larger than in females

Monkeys on the Move

a. As the apes evolved, so did the monkeys in the Old World and the New World expanded and radiated. b. Fossils with cercopithecoid traits first appear in early Miocene. c. The radiation of monkeys continued into the Pliocene and Pleistocene, then declined as habitats and climates changed, or perhaps even due to human hunting.

Coming to America: Origin of New World Higher Primates

a. Four competing hypotheses attempt to explain how anthropoids got to South America. b. Fossil evidence is good for some hypotheses but not for others. c. Some evidence suggests platyrrhines evolved in Africa, then migrated to South America.

Apes Begin in Africa and Dominate the Miocene Primate World

a. The Miocene deposits in Africa provide evidence for a group of primates called proconsulids, which date to 22-17 mya. b. A diverse number of taxa, with 10 genera and 15 species. c. Proconsul is the best known of these genera. d. Skulls and teeth are apelike in appearance; rest of skeleton is monkeylike.

Apes Leave Africa: On to New Habitats and New Adaptations

a. The fossil record suggests apes evolved in Africa and spread to Europe and Asia. b. Apes in Europe: The Dryopithecids c. Apes in Asia: The Sivapithecids d. Dead End in Ape Evolution: The Oreopithecids e. Climate Shifts and Habitat Changes f. Miocene Ape Survivors Give Rise to Modern Apes

Competion for food is especially important to females. nutritional affects

ability to conceive, viability of pregnancy, lactation (For example, at Gombe, female chimpanzees some have access to better feeding resources within the community, and occupy smaller, yet more nutrient dense core areas. These females weigh more, have shorter interbirth intervals, and their daughters reach sexual maturity at a faster rate. In this case, the intake of valuable food items is directly related to gains in fitness. )

when did colobines and cercopithecines diverge?

about 12 million years ago (based on DNA)

what does the origin of anthropoids in the Oligocene reflect?

adaptions to a tougher diet

paradox of group living

advantages of group life, cost of group life

where do the earliest potential hominins appear

africa

miocene

age of apes, earliest human ancestors

basics of the dentition

all primates have teeth in both the upper jaw and the lower jam; bilateral symmetrical mirror-image of teeth on left and right

semi-free ranging

allow animals to establish territories, form their own groups, and forage for food, (compromise between field and captive study)

captive study

allows close observation, study of several generation and behavioral experiments, but they are limited because the setting is unnatural

depositional settings

alluvial fan, fluvial (channel, overbank), lacustrine, coastal, aeolian (loess, dunes), cave/fissure, rock shelter

color vision

an enhanced visual sense has been taken a step further in many primates, most notably around haplorhines

How can monkeys and apes be recognized in the fossil record?

anatomy of their teeth

biped femur angle

angled from hip to knee (bringing the foot directly below the center of gravity)

oligocene

anthropoids

stereoscopic vision enables

arboreal primates to judge distances with precision, which aids in moving rapidly through the trees and predation upon small and fast-moving insects in the terminal branches of trees

these changes in life history patterns, coupled with an extended period of brain growth and maturation, contribute to learning and primate behavioral adaptability

as primates have fewer offspring and those offspring take longer to develop, there is a prolonged period of childhood dependency on mom (and dad), where each offspring receives more care and nourishment in rearing

volcanism

ash, pumices, lavas, basalts, obsidians (Datable Create changed landscapes, open vegetation, erosion Economic utility (stone sources))

Mothers and fathers differ in how much they invest, and how they invest, in their offspring

basically, females invest more in their offspring than do males in most species. We'll see that this asymmetry in reproductive investment has an influence on how males and females distribute themselves with respect to other members of their species.

extended ontogeny is a costly strategy for mom

because it allows for more opportunities for primate youngsters to develop social relationships and learn skills through social mechanisms

middle-late Pleistocene

beginning of OIS 5e ca. 130 ka

Old World Monkey

bilophodont molars

one male, multi female groups (polygyny)

black and white coleus, gorilla

biped pelvis

bowl shaped (ilium rotated around the side of the biped, which reorients the gluteal muscles into a position in which they can provide supper while the biped stands on only one foot)

between-group competition over food resources favors group living

by banding together, primates can more successfully defend access to preferred fruits by members of other groups. Wrangham points out that many primate species feed on fruit and this may explain why so many primates live in social groups.

territoriality

can happen via vocalizations (songs of gibbons) or active defense (inter group aggression and territory patrols in chimps) Why be territorial? Primates should defend their home ranges when food resources are worth defending because of high nutritional value or when males can control females through their defense of territory. BUT territories can only be defended when it is energetically possible and worthwhile to do so.

What are the three settings in which nonhuman primates are studied?

captive, semi-free ranging, field

cebidae

capuchins

Primates obtain nutrients from many different sources

carbohydrates, fats and oils, protein

two secondary curvatures

cervical and lumbosacral regions (keep the center of gravity directly above, rather in front of, the feet of the biped)

males who remain in their natal group

chimps, bonobos, muruquis

field studies

conducted in a habitat in which the species evolved (so researchers can see patterns of heavier that evolved in response to environmental variables)

cones

contain pigments (opsins) that are sensitive to differences in the wavelength of light, perceived as color- most effective in bright light. different types of cones are sensitive to different wavelengths of light, allow mammals to discriminate different colors

competition

contest for mates and resources (The more individuals there are, the more limited resources (both mates and food related) become)

Homiothermy

control of body temperature

logarithmic

decay events per unit of time decrease as concentration of radioactive element is reduced

What is the CP3 honing complex and how does it change during hominin evolution?

def: combination of canine and first premolar teeth that form a self-sharpening apparatus This changes during evolution as canine teeth shorten and the blade on the premolar disappears, the tooth gains a cusp and becomes broader. (pg 248-249)

determinant of male relationships

determined by the degree to which they compete for females, fertilizations cannot be shared

rods

difference in light intensity, black, white, grey

Mosaic evolution

different traits evolve at different points in time

females are dispersed (synchronous breeders)

difficult to guard and monopolize

predation

difficult to study, rare, observer presence may reduce predation (Predation effects are difficult to document given problems of study. First, because predation is a rare event. Not that it is unimportant, but it is difficult to study. Most of the good data that we have come from studies of the predator, not of the prey.Also, when there's researchers around, predators are less likely to come around, so just by observing you're usually changing the likelihood. There was the 1993 study by Lynn Isbel in Kenya, studying vervets, during which they noticed the 'Nairobi effect.' They noticed that a lot of vervets would disappear when they went to Nairobi to get supplies. Not only would more vervets disappear but there'd be more signs of leopards. The rate of disappearances while the observers were present was .04/day, but the rate of disappearances when they'd gone to town was .13/day. This is another reason which makes it not easy to study predation. Big snakes are common predators, as well as crocodiles waiting at waterholes. The most important predators for primates are carnivores and raptors. There are some eagle species which specialize in eating primates. Big cats like lions, leopards, and tigers eat a lot of primates.Larger species are less vulnerable than smaller animals. Also, big animals seem to have more different type of predators, but they get eaten less often. Mortality due to intra-specific killings is generally higher than rates of inter-specific predation. So more primates are killed by members of their own species than from members of other species. A particularly common cause of mortality is infanticide.)

heterodont teeth

diverse functions, incisor, canines, premolars, molars

Changing patterns of monkey and ape diversity in the Miocene seem to reflect what?

drying climate and loss of forested areas

solitary (but different social relationships)

each individual lives alone, may meet up for mating, may choose to neighbor with kin, meet more often

like most other mammals, primates have a heterodoxy dentition

each primate jaw normally contains four types of teeth, from the front to the back: incisors, canines, premolars, and molars. This is in contrast to other vertebrates (above) with homodont dentitions - in all teeth basically look very similar to one another.

eocene

earliest definite primates (adapts, omoyids)

(dating the Pleistocene) electron spin resonance

electron trap technique that measures the total amount of radioactivity accumulated by a specimen (such as tooth or bone) since burial (Developed to measure trapped charge in apatite (heating converts apatite to carbonate) Measure differences in magnetic field created by trapped electrons Used to date tooth enamel. Problem is where does radiation come from? U absorbed into tooth same problems with uptake models as U-Series but added problems of groundwater buffering and intermediate heating Not very reliable)

enclosed bony eye orbit

enclosed (or partially enclosed) bony eye orbits protect the eye. more complete in haplorhines than in strepsirhines

Two major benefits of sociality (though this is not an exhaustive list) are

enhanced access to resources and (2) reduced vulnerability to predation or (likely) some combination of these factors.

the geological time scale divides Earth's history into nested categorizes of time name the four

eons, eras, periods, epochs

more derived skeleton

epiphyses (round ends of long bones), legs under bodies

Ancestral homologies

features primates share with other placental mammals (mammary glands, homeothermy, heterodoxy, neocortex, placenta, maternal care)

females reproductive potential is more limited

females born with limited number of ova (eggs) females can only breed when ova mature and are released

Heavier vs. lighter sediments - exposed surfaces

fine particles may be removed by wind, rain, slopwash, leaving a lag of heavy objects behind

South African site are usually

fissure fills in karats systems that lack volcanic sediments (site ages are mostly based on biostratigraphy and paleomagnetism, with U-series offering a few age estimates)

crepuscular

forage at dawn and dusk

anisogamy

form of sexual reproduction that requires the fusion of two dissimilar gametes (One of the differences between individuals are the underlying reproductive differences between males and females. All reproduction in primates is called anisogamy or "heterogamy" )

coprolite

fossilized poop

anatomical traits that characterize the primate order

generalized body plan, grasping hand and opposable thumb, forward facing eyes with stereoscopic vision (Reduced dependence on sense of smell (olfaction), Increased reliance on sight: forward facing eyes, Stereoscopic vision: allows excellent depth perception; allows for 3D perception), flattened nails, generalized teeth, petrosal bulla, enclosed bony eye orbit

what is petrifaction?

gets replaced by minerals in water turning it to stone

hylobatidae

gibbons or lesser apes

female gorilla behavior

give birth every 4 years, emigrate (At, or after, sexual maturity, females emigrate to other groups, often with sisters or close female kin.)

sediments

glacial features, loess, speleothems, frost-fractured cave deposits, alluvial sediments, lakes, aeolian sediments (dunes)

pongidae

great apes (chimpanzee, bonobo, gorilla, orangutan, humans)

predator defense

group living evolved as a strategy to minimize risk of predation. a wide array of predators hunt primates (including other primates)

bipedal walking

habitual bipedalism affects every region of the body (Human has straight (extended) thigh under body's center of gravity, bird and kangaroo have bent knee to bring leg forward under center of gravity, balanced by tail. We started out without a tail, had to adapt)

biped foot

has arches for shock absorbing and short, straight phalanges

insectivores

have sharp pointy and cresty cusps, for puncturing through the outer skeletons of insects to get at their soft internal parts

Heavier vs. lighter sediments - caves and slopes

heavier objects may roll further downhill, but lighter sediments more likely to be removed by slopewash

Heavier vs. lighter sediments - rivers

heavier objects require stronger current to carry them, and are carried less far in the same current than fine particles

Fractionation

heavy isotopes react more slowly

Heavier vs. lighter sediments - lakes

heavy particles settle to the bottom first

foramen magnum

hole in the occipital bone through which the spinal cord connects to the brain

we live in the...

holocene epoch of the quaternary period of the Cenozoic era of the Phanerozoic eon

proximate

how wan individual organism's behavior functions (immediate reasons for acting- hormonal, physiological)

group living incurs costs such as intra, or within group competition for resources and vulnerability to infectious disease as anyone who got the flu this year can attest

however, given the prevalence of sociality among primates (and other taxa as well including cetaceans) there must be benefits that outweigh these costs

atelidae

howlers, spider monkeys, muriquis

Apes in Europe: The Dryopithecids

i. Larger than earlier apes ii. Resembled living apes in many traits

Apes in Asia: The Sivapithecids

i. Sivapithecus is thought to be ancestral to orangutans due to skull similarities. ii. Even more similar to orangutans is the newly found Khoratpithecus. iii. Also related is the ape Giagantopithecus, which is dated to 8-.5 mya and is thought to have stood nearly 3 m (9.8 ft) tall.

Basal Anthropoids

i. The Oligocene was a period of global cooling and widespread plant and animal extinctions. ii. Most primate fossils from this period come from the Fayum region of Egypt. iii. Fossils from this time period include prosimian fossils as well as those of three groups of higher primates.

The Anthropoid Ancestor: Euprimate Contenders

i. There is debate among scientists as to the ancestors of living primates. ii. One possibility is an Eocene primate called a basal anthropoid.

colobines

include leaf monkeys, langurs, and odd-nosed monkeys. Evolved semi-chambered stomach for digesting tough plant materials in the foregut. Breaks down cellulose that regular stomachs cannot

male dispersal is costly

increased aggression from resident males

population density hypothesis

infanticide is an aberrant and dysfunctional behavior due to high population density (Infanticide is due to high population densities, and is an aberrant and dysfunctional behavior. This was the early explanation. It says that infanticide is a pathological behavior. It isn't part of the normal makeup of the species but is because of abnormally high population densities. Like the way when you crowd lab rats together they kill each other. This made sense for the langurs since one of the groups that was studied was being crowded into little areas by deforestation, and in other study areas people were feeding them and this usually makes levels of aggression rise.)

MATERNAL CARE OF THEIR YOUNG

infants stay with their mothers for a periods of time for lactation, to receive milk from their mothers; so mammalian mothers invest more in their offspring than do nonmammals.

where is the foramen magnum

inferior of the cranium

strepsirhine diet

insects, gum, leaves, fruit

cathemeral

irregular activity during both day and night. activity budgets are linked to dietary quality. higher quality of food, more active. less food quality (more leaves) more sedentary

binocular vision (overlapping fields of view)

is not the same thing as stereoscopic vision (allows for depth perception). You need a brain that is wired to compute differences in the visual information collected from both eyes, and interpret depth from that information.

Chronometric methods

isotopic/radiometric, electron trap

each offspring represents a significant portion of female's lifetime fitness

it is for this reason that mothers are expected to be strongly committed to the welfare of their young

petrosal bulla

its a bony shell that encloses and protects part of the middle ear, and separates it from the interior of the skull. the bulla is formed as an outgrowth of a bone called the petrosal, although you can see that different groups of primates show difference in the detailed anatomy of the petrosal bulla, which you will examine in lab (the significance of this feature is not entirely clear. however, it is a feature that can be reliably used to recognize primates in the fossil record)

What characteristics distinguish non-human primates from other mammals?

large brains and sociality

Resource Defense Model

larger groups generally are more successful in fights over resources than small groups. it is consistent with the observation that primates sometimes compete with members of other groups

What anatomical characteristics would you use to define the genus Homo?

larger, more rounded braincase, a smaller less projecting face, smaller teeth, larger body, shorter arms, striding bipedalism (pg 279)

males who leave their natal group

lemurs, gorillas

human facial prognathism

less, smaller, shorter mandible

Central and Western Africa gorillas

lowland gorillas that live in forests (extremely genetic diverse)

monogamous

males and females live in a pair bond for an extended period of time (social monogamy is not necessarily strict reproductive monogamy, little social dimorphism)

most primates eat a combination of fruit, leaves, other plant materials, insects

many also get occasional protein from birds, amphibians and small mammals. however, the majority of species tend to emphasize one kind of food over others

one female, two male groups (polyandry)

marmosets, pygmy marmoset

metatheria

marsupials- reproduce without the use of the placenta. Individuals are born and in a borderline embryonic state, leave the reproductive tract and crawl into a pouch

reproductive asymmetry has consequences for the reproductive potential of males and females

max number of offspring that an individual can produce

three types of mammals

megatheria, prototherian, eutheria

females clumped

monopolization of fertilizations possible

Prototheria

monotremes, lay eggs but produce milk

chimpanzee facial prognathism

more

carbon isotopes

more heavy carbon in tropical grasses, less in trees and temperate grasses

oxygen isotopes

more heavy oxygen in cold oceans

better access to mates

more individuals= increased mating opportunities

what are the main dietary components of most nonhuman primates?

most herbivores (Primates must balance their calories spent looking for food with quantity (calories consumed) and quality (nutrients like fats, proteins, and carbohydrates)

Primate brains do this extremely well, because our brains are wired differently.

most information from the right eye is taken in and processed by the left side of the brain, while information from the left eye is taken in and processed by the right side of the brain. It's not mixed.

primates are generalized, or retain ancestral homologies, in other aspects of their anatomy

most notably, they have a generalized body plan and dentition. despite being fairly generalized compared to other mammals, primate bodies and teeth also show specific modifications that reflect diversity in how they move (locomotion), and what they eat (diet)

primates therefore have a fairly generalized dentition, which is not specialized for eating only one type of food like many other mammals

most primates have cheek teether with low, rounded cusps, a morphology that allows them to process most types of food

eastern African gorillas

mountain gorillas

foot

non-opposable big toe, enlarged heel (calcaneus), development of arches

hostile intergroup interactions

occur when a desirable food is located in an area where two groups' ranges overlap

Contest Competition

occurs when access to a resource can be monopolized by one or more individuals; some individuals systematically exclude others, and obtain more of the resources Resources patches are clumped, of intermediate size and high value OFTEN SEE AGGRESSIVE ENCOUNTERS IN THIS CONTEXT In this situation, differences in female competitive abilities lead to differences in access.

Scramble Competition

occurs when resources cannot be easily monopolized or defended, and therefore access occurs on a first-come, first-serve basis. Resources are of low value, highly dispersed, or occur in large patches

polyandry

one female, two male groups (marmosets, pygmy marmoset)

Focal sampling

one individual recorded for set period of time (Here, all occurrences of specified actions of one individual are recorded during a predetermined sample period (e.g., one hour). The observer also records the length of the sample period, and the amount of time the focal animal is in view ("time in"). This method can provide unbiased data relevant to a wide variety of questions, particularly if animals remain in the field of view.)

polygyny

one male, multi female groups (black and white colobus, gorilla)

anisogamy

one of the differences between individuals are the underlying reproductive differences between male and females. all reproduction in primates ic called anisogamy or heterogamy

what is the taxonomic group that contains all the primates?

order

what are the principles of stratifigraphy?

original horizontality (rock layers are deposited parallel to Earth's surface), superposition (older layers are covered by more recent layers), cross-cutting relationships (a geological feature must exist before another can cut across it, the cutting feature is younger), faunal succession (the community of fossilized animals in a section changes predictably with time' older fauna are lower in the section; once a species goes extinct, it does not reappear higher in this section)

While the skeleton of the HUMAN trunk, shoulders, and upper limbs retains some of those features that allow for suspensory behavior in living apes,

other parts of the human anatomy, particularly the pelvis, spine, and lower limb, show dramatic changes, reflecting an adaptation for habitual upright walking.

primates

over 300 recognized primate species, highly variable in size, shape, behavior, locomotion, cognition

between-group competition

over food resources favors group living, so that individuals WITHIN groups can cooperate in joint defense of those resources.

human teeth

parabolic dental arcade, Smaller anterior teeth

haplorhine traits

partial post-orbital enclosure, no tapetum, lucidum, no rhinarium, fused frontal bone

many primates also evolved color vision,

particularly in diurnal (day active) species, which allows them to distinguish similar colored objects, such as fruits and young leaves (often lighter in color) against a background of mature leaves

terrestrial species tend to form larger groups than arboreal species

perhaps because life on the ground is riskier than life in the trees

Eutheria

placental mammals, includes primates. Individuals reproduce via internal fertilization in which a fertilized zygote implants on the uterine wall. The placenta allows offspring to develop longer inside the mother by tapping into the energy and oxygen carried in her blood. Length of gestation and offspring development at birth is highly variable across Eutherian species.

flora

pollen diagrams

Early dental apes such as Proconsul have

post cranial skeletons (similar to those of monkeys) and Y-5 dental patterns of apes

diet and teeth

primates are generally quite omnivorous compared to other mammals, meaning they don't specialize on only one kind of food, but rather they are capable of eating a variety of different food items derived from both animals and plants

primate suborder

primates can be divided into two sub orders based on genetic relationships. other systems of taxonomic classification exist that divide groups based on anatomy (prosimian vs anthropoid)

primate suborders

primates can be divided into two sub orders based on genetic relationships. other systems of taxonomic classification exist that divide groups based on anatomy (prosimian vs anthropoid)

large brains

primates have a high degree of encephalization, or an increased brain size. in primates, the neocortex is pronounced, which is important as this area of the brain is involved in higher-order cognitive processes

In 1980 Richard Wrangham put for the Resource Defense Model, which states that

primates live in groups because groups are more successful in defending access to resources than lone individuals

primate evolution

primates or primate ancestors appear around 63 million years ago and diversity into niches created by the extinction of the dinosaurs, but they do not show most of the anatomical characteristics of living primates. Strepsirhine and haplorhine lineages appear in the early Eocene. The first monkeys with postorbital closure appear in the Oligocene. Apes diversity in the Miocene but are rare by the Pliocene.

lorises and galagoes

probably resemble the primitive ancestors of modern haplorhines. Recent research shows that lorises and galagos may actually be social in certain circumstances.

So why would a male ever leave his natal group?

proximate causes (Parental aggression Conspecific aggression Innate genetic switch) ultimate causes (Inbreeding avoidance Competition for mates Competition for resources) (Males who remain- chimps, bonobos, muruquis Males who go- lemurs, gorillas)

potassium-argon (K-Ar) dating

radiometric technique using the decay of 40K to 40Ar in potassium-bearing rocks; estimates the age of sediments in which fossils are found (Discovered in 1960's Decay of ca 10.5% of radioactive isotope of K40 to A40 in rocks Half life of 1.25 billion yrs, effective range 2,000-7 billion years Requires starting point with no A40, usually need volcanics Radiogenic A trapped in crystal lattices (e.g.feldspars), heat to release and measure Step-heating controls for diagenetic argon leakage or "old" argon Irradiate sample to convert %of K39 to A39 which does not exist in nature--% of A39 is proportional to % of K, allows direct measurement of A39 /A40 in same lab step instead of separate measurements of K and A Allows measurement of very small samples (single crystals) using mass spectrometer, eliminate contaminated crystals)

(dating the Pleistocene) Radiometric- Uranium series techniques

radiometric techniques using the decay of uranium to estimate an age for calcium carbonates, including flowstone, shells and teeth (Uranium in newly formed rocks or adsorbed into bones, teeth after burial U decays to Pb over very long half-life Big atom - decays to daughter products first over shorter half-lives U238 to U234 (248kyr) to Thorium230 (75.2kyr) U235 to Protactinium231 (34.3 kyr) (rarer) Combined age range ca. 5-500 kyr U is soluble in groundwater,Th and Pa insoluble so only U can be absorbed from groundwater Need (1) sample formed at time of interest, (2) no Th or Pa to start with, (3) closed system Speleothems, Travertine, Calcrete, Tooth enamel or dentine, silicified plant stems Most dating on teeth - problem of when does uranium get in (early or late uptake), bone is not closed system Speleothems (stalagtites, -mites) are more reliable)

biostratigraphy

relative dating technique using comparison of fossils from different stratigraphic sequences to estimate which layers are older and which are younger

So not only must primates learn how to use their environment and acquire food, they must also learn how to navigate the relationships and social complexities associated with living in groups.

relatively large brains and long developmental periods are one way primates are able to do this

male gorilla behavior

remain in their birth group, (Silverback - adult male Blackback - adolescent male Males can remain in their birth group and wait to join ranking silverbacks to breed some day. Young silverbacks can also live on their own or in bachelor groups waiting for opportunities to either drive out a current silverback from their group or to steal a female or two and establish their own group.)

The distribution of food effects competition clumped=contest competition

resources are scarce and valuable Worth fighting over Direct competition

contagion

respiratory disease (One of the most common causes of death and illness in primates is respiratory disease. Among other contagions that have been reported include diseases such as ebola. This virtually wiped out a group of chimpanzees at Tai, Cote d'Ivoire. Also endemic to primates is the disease SIV, or simian immunodeficiency virus, related to HIV in humans. The most southern community at gombe is plagued by SIV, and numbers are rapidly dwindling in this population. One individual in the well-studied Kasakela community, Ericki, has disappeared from the community and is thought to have succumbed to SIV. He is an interesting case as his mother is not positive for the disease. This is one example of disease transmission. Heightened risk in groups!)

interbreeding

results when two closely related individuals reproduce. The result is an increase in homozygosity, which increases the chances that an offspring is affected by a recessive or harmful trait. This can lead to the overall decreased fitness of a population, which is called inbreeding depression. (A famous albino gorilla that lived for 40 years at the Barcelona Zoo got its white coloring by way of inbreeding, new research shows. Snowflake was a male Western lowland gorilla. He was born in the wild and captured in 1966 by villagers in Equatorial Guinea. As the only known white gorilla in the world, Snowflake was a zoo celebrity until his death of skin cancer in 2003. A few studies had attempted to get to the bottom of what caused Snowflake's color-free complexion, but the exact genetic mutation had never been found. Now, Spanish researchers have sequenced the gorilla's entire genome, revealing that Snowflake was probably the offspring of a pairing between an uncle and a niece.)

hominins include

sahelanthropus, orrorin, ardipthecus

pithecidae

sakis and related species

pleistocene

sea levels drop, animals migrate or go extinct, ice expands, ties up global water

life history traits that characterize the primate order

single births, large brain-body size ratio (Heavy parental investment in single offspring.) Large brains. Increased encephalization (increase in the volume of the neocortex of the brain). Extended ontogeny (development since birth). They live by both learned behaviors from their social groups and as well as instinct.

petrosal bulla

single bony trait shared by all primates which occurs in no other mammals group. tiny piece of skeleton protecting inner ear

species that typically do not forage in groups, such as orangutans, chimpanzees and spider monkeys are large in body size and apparently face little danger from predators

small bodied primate species are more vulnerable to predation than larger ones; and young primates are generally more susceptible to predation than adults

Australopithecus species

small-bodied, small brained, bipedal African apes with both primitive and derived characters

However, in primates, each half of the brain takes in and processes information from the entire VISUAL WORLD on the opposite side - not just the opposite eyeball.

so information from both right and left visual fields is mixed, in a way that allows the brain to calculate differences in the position of objects viewed from both eyes and interpret depth from this

tool use

socially learned behavior, transmitted via generations. As individuals grow, become more efficient at extractive foraging tasks.

Tarsier characteristics

solitary, nocturnal, eats mainly insects, VCL locomotion

organgutans

solitary- females defend territory from other females, males try to gain access to several female territories Bimaturism- males can take two forms- flanged, or "adolescent" Extended ontogeny- 8 year IBIs female sexual maturity 11-15, male sexual maturity 15

males-reproductive potential is very high

sperm are smaller and more numerous, constantly replenished, males can fertilize whenever sperm are replenished

mobbing

strength in numbers (A lot of animals do this too. You can see songbirds mobbing owls or crows right around campus. They move toward the predator harassing and screaming until they drive it off. Examples in primates: baboons will mob any small carnivore, even cheetahs and jackals. When an animal lives in large groups, it can mob large predators which it couldn't do if it was alone. Chimps have been seen to mob leopards and lions. Rhesus monkeys have been seen to mob tigers.)

The left side of the primate brain

takes in everything on the ENTIRE RIGHT SIDE OF THE VISUAL WORLD - including overlapping information gathered from BOTH eyes, including information about parallax.

However, leaves also come with very fiber-rich cell walls

that are very difficult to digest; primates that specialize on leaves have special adaptations of the teeth and guts that facilitate the breakdown of fibrous materials, enabling them to access the protein in young leaves - Most colobines (colobus monkeys) eat leaves and have enlarged large intestines

several kinds of scenarios have been produced for the origin of hominid including

that bipedality is more energy efficient than knuckle-walking and allows the body to dissipate heat faster; for this reason, bipedalism might be favored, especially in a savannah environment OR postural adaptions to particular food resources (from trees, or specialized grasses) might favor bipedalism OR freed hands that can be used to carry infants, weapons, or food may favor bipedalism

One British anatomist (Wilfred LeGros Clark,, 1895-1971) suggested

that primates are best defined in terms of a suite of adaptive trends (These are features that characterize the primate order as a group, although they may not be as fully expressed or present in all primate species. Many of these features are thought to be connected in some way to the demands of living life in the trees - although researchers differ on the details, many of these features are thought to have evolved in response to living and feeding in the arboreal habitat that most primates live in today, and which was most likely the habitat of the earliest primates in the past.)

Ecological theory predicts

that when two or more organisms with similar needs are sympatric (sharing the same space) they will diverge from one another in some critical aspect of their niche (ecological role). Without niche separation, they would drive each other into extinction. Polyspecific groups

how did the climate change from the Paleocene to present?

the Paleocene and Eocene epochs were substantially warmer than today

fitness

the ability to survive and reproduce (As we know from our understanding of natural selection, the environment places pressure on individual organisms. Because of variation in traits, it is inevitable that some individuals are better suited to survive than others. These individuals will pass their genes along to the next generation. These individuals are "fit". So, how does this happen?)

2 hypotheses for the origins of stereoscopic vision in primates include

the arboreal hypothesis- matt cartmill- states that stereoscopic vision, grasping hands, and opposable thumbs are a suite of characteristics that evolved for life in the trees. However, squirrels have incredibly agility and live in trees quite well without most of these features. A revised hypothesis was put forth called the Visual Predation Hypothesis- these adaptations (forward-facing eyes, depth perception, grasping hands) evolved for catching prey.

hominins teeth characteristics

the canine is reduced in size and lacks a functional CP3 honing complex

geological time scale (GTS)

the categories of time into which Earth's history is usually divided by geologists and paleontologists: eons, eras, periods, epochs

vertebral column

the column of bones and cartilaginous disks that houses the spinal cord and provides structural support and flexibility to the body

biped femur condyle

the femoral condyles are enlarged to bear greater weight, and the groove for the patella is deep

lumbar vertebrae

the five vertebrae of the lower back

coccyx

the fused tail vertebrae that are very small in humans and apes

sacrum

the fused vertebrae that form the back of the pelvis

cost of within-group competition will offset the benefits gained in between group competition

the individuals in larger groups will incur those costs. the balance between within and between group competition will be different for different species

infanticide

the killing of infants, either by members of the infants groups or by a member of a rival group (Infanticide occurs in lots of different kind of birds including common ones like sparrows, and swallows. It also happens in rodents like mice and ground squirrels. You also see it in lions. It's a similar sort of situation- females live in matrilineal groups and only the males disperse. A set of several males (usually related) live with the group and enjoy mating privileges until they're driven out and then the new males kill all the babies.There are plenty of infanticidal primates- lemur catta, red howlers, red colobus, silver leaf monkeys. There are several cercopithecine examples- red-tails, blue monkeys among them. A couple of different savannah baboons, and also chimps and gorillas among the apes.)

continental drift

the movements are critical for understanding early primate evolution, particularly the distribution of the Eocene primates and the conundrum of the origin of the South American primates

what is the one defining characteristic of primates, the one feature that all primates share?

the petrosal bulla. the one trait that characterizes all primates, to the exclusion of all other mammals

cervical vertebrae

the seven neck vertebrae

paleontology

the study of extinct organisms based on their fossilized remains

lithostratigraphy

the study of geologic deposits and their formation, stratigraphic relationships, and their relative time relationships based on their lithologic (rock) properties

socioecology

the study of how ecological forces shapes the size and structure of social groups

taphonomy

the study of what happens to organic remains from the time of death until discovery

thoracic vertebrae

the twelve vertebrae of the thorax that holds the ribs

the foundation of the socioecology model is rooted in the concept of reproductive asymmetry

there is asymmetry in the extent to which males and females invest in reproduction and offspring care, and this plays a key role in understanding the nature of primate social strategies and relationships

predation is a major contributor to mortality among wild primates

therefore, natural selection should act on animal behavior to evolve strategies that reduce this source of mortality. Carel van Schaik 1989. Primates hunt other primates. Chimps hunt red colobus, baboons prey on infant vervet monkeys. Rates of predation in primate species can range up to more than 15% of the population per year.

how are the principles of stratigraphy important to the formulation of the geologic time scale

they are critical to understanding the context of a fossil

most mammals have only two types of opsins, short and middle wavelength of light

they are dichromatic (middle), can perceive blues and greens

strepsirhine traits

two grooming claws, insectivore, small-bodied

many orders of mammals are recognized on the basis of very distinctive specializations

unlike these other mammalian orders, however, members of the order Primates are not characterized by such conspicuous traits. this fact has lead to some difficulties concerning how to define the order primates

incisors

usually "spatulate" in form

example of primate that uses alarm calls

vervet monkey (A lot of animals use alarm calls, primates included. How important they are depends on the size of the species. For instance, there are studies on vervet monkeys' alarm calls by Cheney and Seyfarth. Vervets have several different patterns of alarm calls. One call is for airborne predators. When this call is heard, they'll run down from the trees. There is a different alarm call for ground predators, which when heard they run into the trees. The last is for snakes, and they don't run anywhere but instead stand up on their hind legs and look around carefully. Other primates, such as Gorillas for example, have alarm calls too but they are used less often and aren't as specific.)

alarm calls

vervet monkeys distinguish between types of predators. Gombe chimps kill colobus

behavioral traits that characterize the primate order

visually oriented daytime activity, sociality (Diurnal (active during the day; rely on vision) or nocturnal (active during the night; rely on smell). All haplorhines are diurnal except for night monkey Aotus. Sociality: solitary or group-living. Group-living provides animal with ready access to mates, help it find food, and avoid predators. Sleeping, traveling, eating, grooming, playing.)

East African sites are often associated with

volcanic ashes or tephra (because of this 40AR/39Ar chronometric dating is possible, as are relative dating techniques, such as biostratigraphy and tephrostratigraphy, and calibrated relative techniques, such as paleomagnetism)

homeothermy

we can control our body temperature through physiological mechanisms, and we can do this independently of the environment (Reptiles (turtles, crocs, lizards) must derive their heat from the environment, regulate body temperature through behavior. Mammals have hair or fur for insulation, sweat glands for homeothermy)

emigration

when an individual leaves his/her natal community, usually at sexual maturity

when does fossilization occur

when skeletal remains absorb minerals from the surrounding environment

Ultimate

why a species evolved the behavior it has (Named after Nicholast Tinbergen, a dutch ethologist who won a nobel prize for his efforts in understanding individual vs. social behavior in animals. Tinbergen's 4 questions are complementary categories of explanations for behavior)

pelvis shape

wide, basin-shaped pelvis, short, broad, curved iliac blades

primates are also characterized by a tendency to live in social groups

with a permanent association of older juveniles and adult males. permanent association of adult males in the group is unusual for mammals, but is widespread among primates

frugivores

with low rounded cusps. Think of when you eat fruit, you use your back teeth primarily for mashing and grinding, rather than shearing. This mortor and pestle type action is accomplished by teeth with low and rounded cusps

Knuckle- walking

wrist joints are stabilized

Are apes abundant in the early Miocene?

yes

are monkeys abundant in the miocene?

yes

are monkeys are few in the miocene?

yes

how do relative and chronometric dating techniques differ?

• Dating techniques are used in archeology to ascertain the age of old artifacts and a broad classification of these methods bifurcates them in relative dating and absolute dating • Relative dating comes to a conclusion based upon the study of layer formation of rocks. Upper most layers are considered the youngest while the lowermost deposition is considered as oldest. • Relative dating does not tell the exact age, it can only compare items as younger and older. • Absolute dating techniques can tell the exact age of an artifact by employing various techniques, the most popular being C-14 dating.