Primate Origins Chapter 8 – Flashcards

Anthropologists specializing in the study of the nonhuman primate fossil record

found in sedimentary deposits, photosynthetic mats of cyanobacteria, fossil evidence

Taxonomy is the science of classification of organisms. Primates are difficult to classify. Most scientists classify primates, monkeys, and apes in the Kingdom Animalia, the Phylum Chordata (animals with a supporting rod along the back, this also includes sharks and rays), Subphylum Vertebrata (animals with a bony backbone), the Class Mammalia, and the Order Primates. As of 2004, there are 363 species of primates. In addition to monkeys and apes, the order includes prosimians ("premonkeys") such as lemurs and bushbabies as well as humans. As mammals, primates possess the mammalian characteristics of endothermy (internal regulation of body temperature, often known as warm-bloodedness), bearing live young (placental), and feeding their young with milk produced by mammary glands. Not all primates possess the same characteristics—there is no unique characteristic that defines a primate. Most shared characteristics and trends are not derived but instead are a retention of ancestral features, which also adds difficulty to classifying primates. Many of these characteristics are behavioral, or depend on soft tissue anatomy; this does not help in identifying fossil primates. This retention of a fairly generalized body type, unlike hoof stock for example, reflects their diversity of life style. Their unspecialized morphology and highly flexible behavior allows them to fill many niches and adapt to environmental change. There is a number of rather specific primate characteristics, such as details of the bones of the foot and skull. However, these characteristics do not make it easy for scientists to categorize early mammals and primates. There are a few scientists who consider tree shrews primates and bats the closest living relative to primates. Some distinguishing characteristics of primates include: Forward-facing eyes for binocular vision (allowing depth perception) Increased reliance on vision: reduced noses, snouts (smaller, flattened), loss of vibrissae (whiskers), and relatively small, hairless ears Color vision Opposable thumbs for power grip (holding on) and precision grip (picking up small objects) Grasping fingers aid in power grip Flattened nails for fingertip protection, development of very sensitive tactile pads on digits Primitive limb structure, one upper limb bone, two lower limb bones, many mammalian orders have lost various bones, especially fusing of the two lower limb bones Generalist teeth for an opportunistic, omnivorous diet; loss of some primitive mammalian dentition, humans have lost two premolars Progressive expansion and elaboration of the brain, especially of the cerebral cortex Greater facial mobility and vocal repertoire Progressive and increasingly efficient development of gestational processes Prolongation of postnatal life periods Reduced litter size—usually just one (allowing mobility with clinging young and more individual attention to young) Most primates have one pair of mammae in the chest Complicated social organization

Oligocene or possibly near the end of the Eocene.

It was likely a short-limbed, heavily muscled, slow moving arboreal quadruped. It was long viewed as the best candidate from the Fayum to have given rise to Old World monkeys, apes and humans.

Species identified from fossil remains based on their physical similarities and differences relative to other species. species defined from fossil evidence, often covering a long time span.

The earth went from the Oligocene through the Miocene and into the Pliocene as it cooled into a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regional boundaries between the warmer Oligocene and the cooler PlioceneMiocene Epoch (24-5.3 mya) Early in the Miocene, temperatures begin to rise. Extensive mountain building in the Americas and Asia alters air circulation and weather patterns, contributing to drier overall conditions. Antarctica's separation from South America during the Oligocene, however, inhibits the mixing of warm, tropical waters with cool, polar waters. Antarctica freezes, and global climate cools again. Marine mammals like seals and whales flourish as deep, nutrient-rich waters are stirred up in the process.What sort of climatic and geological changes occurred during the Miocene and how would these changes have affected the evolution of the first ape-like primates? During the miocene we see a lot of geogrgraphical changes. Contintental drift was continuing, causing changes in the rock and also changes in weather patterns. During the beginning of the period, there was a lot of movement from the plates that caused lots of rifts in the land - creating volcanoes. In certain places the weather was really warm, while in others became wetter as their was much more rainfall. Another big change was that during this time, the Earth was going through an overall cooling pattern, and the sea level decreased because a lot of water became frozen in ice caps. Because of the sea level going down, there was land exposed that connected Asia and Africa, which gave primates the opportunity to move into previously innaccessible lands. In certain areas during the Miocene, we see that in some places forrests began to be replaced by savvanahs and dry grasslands. There were much less trees in the area at this time. Scientists beleive apes evolved from monkeys during this period, and the fossil record supports this notion - there are many more ape fossils found than monkeys during this time. Since the landscape was changing, and savannas or grasslands were more common than trees, terrestrial primates like apes did well in the new environment. It is beleived that the ancestors of modern humans were around during the miocene, when primates began to adapt to the new life in the savvanas. During the miocene there was a short period of warming, during which scientists beleive that the apes did most of their evolving. By the end of the Miocene there was another cooling trend, which is beleived to have caused the extinction of many species that were left in the Northern areas, which became too cold to inhabit. The primates that were able to migrate down south in places like Africa and East Asia are beleived to be some of our earliest ancestors.

the first true apes , those belonging to the superfamily Hominoidea, appear during the early to middle Miocene 17mya. first in europe, presumably coming from an African proconsuloid ancestor.

shared derived traits

Last Common Ancestor

linked continents of North America, Europe, Asia

oldest primate-like animal with reasonable fossil record from the Paleocene

64-65 may first archaic primates, plesiadapiforms

55-35 mya true prosimians do appear before Europe and North America separated. they probably spread to Africa from Europe. The climate was right by this time for adaptive radiation of primates. first euprimates, early strepsirhines and haplorhines.

now considered a mammal and it does have some primate like characteristics like a long tail, agile limbs, and claws instead of nails

An evolutionary pattern in which many species evolve from a single ancestral species Evolution from a common ancestor of many species adapted to diverse environments

a find from Europe, most intriguing fossil discovered, to date, is 47 mya Darwinius massillae. Interesting for several reasons 1. Ida is a complete skeleton 2. lacks a dental comb and a grooming claw

the incisors and canines on lower jaw that protrude outward for grooming

Strepsirrhine primates have secondarily evolved a claw -- that has replaced the flattened nail -- on the second pedal digit. This claw serves a grooming function.

inhabited Europe and North America, Asia, Africa. most diversified of the Eocene primates. show a close resemblance to the loris and lemur.

know for its forward rotated orbits, grasping hands and big toes, nails vs. claws, and shift forward in the foramen magnum.

Opening in the floor of the cranium where the spinal cord exits the skull.

lived in Europe, North America and Asia. chacteristics similar to tarsiers. forward rotated eyes, that were encased in bone, short snout and an upside down v shaped jaw.

live in south east asia, nocturnal hunter of insects, frogs and reptiles, clinging-leaping, solitary hunters, pair bonds and small groups. classified as an early primate

A small, slow-moving nocturnal primate with a short or absent tail, living in dense vegetation in South Asia.

Madagascar; vertical clinging and leaping, legs built like springs

evolutionary shifts in behavior during this time period, diural vs. nocturnal activity, climbing and quadrupedalism vs. leaping, eating insects vs. just fruits/vegetables. Climate is cooling, forcing the movement of primates to southern areas.

34-24 mya, early catarrhines, precursors to monkeys and apes.

section where the Nile splits and makes a swampy area perfect for preserving things 30 miles outside of Cairo, Egypt. In general the fayum fossils show anthropoid dental features, but lack locomotor characteristics.

size of squirrel, eat fruit and seeds, arboreal quadruped, OLIGOCENE small, arboreal quadrupeds, dental pattern shows an extra premolar, a possible dental pattern of all early anthropoids. with 36 teeth. this characteristic is also found in New World monkeys, which could show a relationship between the two groups.

23-5 mya, monkeys and apes, first humanlike creatures.

continents had drifted apart,

members of the primate suborder Strepsirhini, which includes lemurs and lorises.

members of the primate suborder Haplorhini, which includes tarsiers, monkeys, apes, and humans.

being or having a feature that is not present in the ancestral form.

referring to an upright body position. This term relates to the position of the head and torso during sitting climbing, etc., and doesn't necessarily mean that an animal is bipedal.

a taxonomic group ranking above an order and below a class or subclass.

the relationship of new clades that result from the splitting of a single common lineage.

the final evolutionary link between two related groups.

all of the taxa that come after a major speciation event. Crown groups are easier to identify than stem groups because the members possess the clade's shared derived traits.

a taxonomic group of any rank, species, family or class.

all of the taxa in a clade before a major speciation event. Stem groups are often difficult to recognize in the fossil record since they don't often have the shared derived traits found in the crown group.

the taxonomic category above suborder and below order.

True primates. This term was coined by Elwyn Simons in 1972.

referring to all or part of the skeleton not including the skull. The term originates from the fact that in quadrupeds the body is posterior to the head; the term literally means behind the head.

bone not old enough to have become completely mineralized as a fossil.

referring to molars that have four cusps oriented in two parallel rows, resembling ridges or lophs. This trait is characteristic of Old World monkeys.

anthropologists specializing in the study of the nonhuman primate fossil record.

a method of dating strata that relates the fossil content of an unknown stratum to a like one that has been securely chronometrically dated.

members of Carrhini, a parvorder of Primates, one of the three major divisions of the suborder Haplorhini. It contains the Old World monkeys, apes and humans.

a specific taxonomic category above superfamily and below infraorder, a taxon

a group of one or more populations of an organism or organisms seen by taxonomists to form a unit.

members of Platyrrhini, a parvorder of Primates, one of the three major divisions of the suborder Haplorhini. These include only the New World monkeys.

traveling from one island to the next.

molar that has five cusps with grooves running between them, forming a Y shape. This is characteristic of hominoids.

cheekbones

living and locomotion primarily on the ground.

Epoch-miocene/sites Kenya Africa/the first apelike primate to leave Africa; may have given rise to the European apes; thick-enameled teeth and Y-5 pattern molars.

Epoch-Miocene/Germany, Slovakia, Turkey, Eastern Europe/Western Asia/the first true ape; may have given rise to both the later radiations of European and Asian apes; no tail.

Epoch-late Miocene/Greece, Europe/Fossil great ape; believed by may to have returned to Africa to give rise to the living great apes and humans.

Epoch-late Miocene-early Pliocene/China, Asia/Part of the Asian fossil great ape radiation; stem orangutan.

Epoch-Miocene Pleistocene/China, Vietnam, India, Myanmar, Asia/ The largest ape that ever lived; only great ape to go extinct in the Pleistocene.

sideways facing nostrils, no ear tube, grasping tail

downward-facing nostrils, ear tube, ischial callosities

5.3 to 0.01 may early homo

0.01 to present modern humans

any of a family (Hominidae) of erect bipedal primate mammals that includes recent humans together with extinct ancestral and related forms and in some recent classifications the gorilla, chimpanzee, and orangutan

Oligocene, 30 to 25 myaThe oldest Old World Anthropoids come from a single Oligocene dated area, the Fayum, about 30 miles outside of Cairo, Egypt. The Fayum environment was a combination of tropical forest and swamp. In general, the Fayum fossils show anthropoid dental features, but lack locomotor characteristics. The largest group of Fayum primate fossils are the species Apidium. These small, arboreal quadrupeds existed on a diet of fruits and nuts. Their dental pattern shows an extra premolar (a possible dental pattern of all early anthropoids), with a total of 36 teeth. This characteristic is also found in New World monkeys, which could show a relationship between the two groups.