CHAPTER 16 Primate Evolution WHAT IS A PRIMATE

CHAPTER 16 Primate Evolution

WHAT IS A PRIMATE ?

A PRIMATE IS… Humans Apes Monkeys Lemurs Group of Mammals characterized by having nails on their hands and feet, a short snout, and a large brain.

WHAT ARE SOME CHARACTERISTICS OF PRIMATES?

CHARACTERISTICS OF PRIMATES. . • Flexible hands and feet • High level of dexterity ( This allows them to be able to grasp onto objects and move them around in their hands) • Well developed eyesight • Long mobile arms • Large brains (with this comes reasoning)

WHY IS AN OPPOSABLE FIRST DIGIT IMPORTANT? * Opposable digits The hands and feet of all primates have… 5 digits Flat nails Sensitive areas on the end their digits The first digit of the hand or feet are opposable. Thumb or Toe Set apart from other digits Can cross palm and touch other side are what gives primates the ability to grasp objects and move them in their hands.

HOW DO FORWARD LOOKING EYES BENEFIT PRIMATES? • Primates rely more on their vision then any other sense • They have from facing eyes • This creates a overlapping field of vision (binocular vision) • Forward facing eyes allows for better • Depth perception - Judgment of object placement and movement. • Diurnal • Active during the day • Color vision • Nocturnal • Active at night • Black and white vision *Along with these changes came smaller snouts, Flattened faces (binocular vision) , and unspecialized teeth.

HOW DO PRIMATES MOVE? • Primates rely on their hind limbs for movement • On the ground all primates except for humans walk on all four limbs • Some primates live in trees • Along with their flexible limbs (shoulders) they are able to move from branch to branch.

WHAT ARE SOME CHARACTERISTICS OF A PRIMATE WHAT IS THE BRAIN? REPRODUCTI VE RATE OF PRIMATES? Primates have large brains with large areas devoted to. . • vision / few to smell • Memory • Arm to leg movement Because of their brain size they are able to. . • Solve problems • Engage in social behavior • Communicate through complex ways (facial expressions) Female primates have a long pregnancies Give birth to one offspring at a time Infant is very dependent on mother for years ( Social skills )

• Most primates are Arboreal (ar BOHR ee uhl) or tree-dwelling PRIMATE GROUPS CLASSIFIED INTO TWO SUBGROUPS • Live in tropical and subtropical rain forest STREPSI RRHINES • “Wet nosed” primates • Earliest and most basic primates • Lemurs (most members) HAPLOR HINES • “Dry nosed” primates • Human like primates • Tarsier ( unique primate)

STREPSIRRHINES • Rely mostly on smell for hunting and social interactions • Have large eyes and ears • Live in tropical Africa and Asia ( Madagascar and islands) • Scientist believe that these animals evolved in isolation when the island of Madagascar drifted from the content of Africa. Strepsirrhine Lemurs s group Aye-ayes Lorises Galagos Active period Large-diurnal Smallnocturnal Nocturnal Mostly nocturnal Range Madagascar Africa and southeast Asia Africa Features • Vertical leaper • Uses tail for balance • Herbivores and Tap bark, • Small, slow listen, fish on climbers; grubs with solitude long third • Lack tail finger. • Some have toxic

Tarsiers Monkeys HAPLORHINES Apes Tarsiers • • Gibbons Orangutans Gorillas Chimpanze es • humans • Live in Borneo and the Philippines • Nocturnal • Large eyes • Lives in trees *can turn its head 180 degrees

ANTHRO POIDS • larger than Strepsirrhines • larger brains for their body size • Diurnal- color vision • Complex social interactions NEW WORLD MONKEYS The Americas OLD WORLD MONKEYS Africa Asia Europe

WHAT TRAITS DO NEW WORLD MONKEYS SHARE? • Live in the tropical forests of Mexico, Central America, and South America • Include • Marmosets • Tamerins *No nails or opposable digits *Some squirrels and spider monkeys have • Diurnal • Live in social bands • Have prehensile tails (work as a fifth limb) • Can grasp trees and support entire

WHAT FEATURES DISTINGUISH OLD WORLD • Live in a wide variety of habitats throughout Asia and Africa MONKEYS? • Two subgroups 1. Macaques and baboons 2. Colobus and proboscus • Diurnal • Live in social groups • Narrow noses • Larger bodies • Spend more time on the ground • Some do not have tails • Most have opposable digits

HOW DO APES DIFFER FROM MONKEYS? Classified into two groups: 1. Lesser apes ( gibbons • Larger brains and siamangs) • Arms are longer than legs 2. Greater apes (orangutans, • Barrel-shapped chests gorillas, chimpanzees, and • No tails humans) • Flexible wrists • Highly sociable • Make complex sounds

HOW DO LESSER APES TRAVEL THROUGH THE TREES? Brachiation – using a hand-over-hand swinging motion

HOW DO GREAT APES WALK? Orangutans Largest arboreal primates Large males spend more time on the ground Live exclusivity In Asia Gorillas • Largest primates • Spends most of its time on ground • Walk on all four limbs Chimpanzees and bonobos Knuckle walkers Well-developed communication and social systems More like human in physical structure and behavior than other primates

TO WHAT CATEGORY DO HUMANS BELONG TO ? • Humans are part of the greater apes family • Classified as hominins Hominins are human like primates that appear to be closely related to present day humans than they are to present-day chimpanzees and bonobos Humans are the only species of hominins that exist today, others extinct

PRIMATE EVOLUTION As we discussed in earlier slides most primates today have some common traits • Are arboreal • Have prehensile tails • Long limbs • Binocular vision • Brachiation • Opposable toes and thumbs * with these traits primates are better adapted to live in trees

HOW MIGHT HAVE PRIMATES BECOME ARBOREAL? • Scientist suggest that primates have evolved from land-living animals that gathered their food from the top branches of various shrubbery. • This suggest that the opposable thumbs and flexible hands of primates may have evolved to catch food rather than to hold onto tree branches. • Other scientist suggest that the rise of flowering plants provided new niches for primes to evolve to. • Arboreal adaptations enabled primates to gather fruits and flowering trees. *A niche refers to the way in which an organism fits into an ecological community or ecosystem. Through the process of natural selection, a niche is the evolutionary result of a species' morphological (morphology refers to an organism's physical structure), physiological, and behavioral adaptations to its surroundings.

WHEN DID THE FIRST PRIMATES APPEAR? • It is believed that the first primates lives alongside the dinosaurs about 85 mya. • One of the earliest fossil primates, called Altiatlasius (al tee aht lah SEE us), was a small, nocturnal animal that used its hands and feet for grasping. • About 50 mya, anthropoids branched off from tarsiers. At the end of the Eocene, 35 to 30 mya, anthropoids had evolved widely.

WHEN DID DIFFERENT LINES OF MONKEYS DIVERGE? • Monkeys first appeared at the end of the Eocene between 35 and 25 mya. • By this time, Africa and South America had separated into two continents. • Some scientist believe that New world monkeys evolved from a group of old world monkeys that drifted to S. America on rafts of vegetation. • Other scientists believe that new world monkeys branched from anthropoids that traveled to S. America earlier when sea levels were low.

WHAT ANIMAL MIGHT HAVE GIVEN RISE TO APES? • Many anthropoids fossils have been found in the fayum basin in Egypt. • Aegyptopithecus (ee gypt oh PIH thuh kus) or the dawn ape, is the largest (size of house cat) • Some scientist believe that this animal was part of the anthropoid line that splits from old world monkeys. • This line led to orangutans, gorillas, chimps, and

HOMINOIDS TO HOMININS

HOMINOIDS • By comparing DNA of living hominoids species, researchers conclude that gibbons likely branched from anthropoids first. • Next to the branch were orangutans, gorillas, chimps, and bonobos, and finally humans. • *chimps and bonobos are the closest living relatives to humans. *Include all nonmonkey anthropoids: gibbons Orangutans Chimps Gorillas Humans.

WHAT CHARACTERISTICS TO HOMINOIDS SHARE ? • Largest primates • Largest brains for body size • Broad pelvis • Long fingers • No tail • Flexible arm and shoulder joints • Upright posture • All but hominins have longer arms and legs • Less specialized teeth ( can eat a variety of food)

HOMININS • Include humans and all their extinct relatives. • Split from other African apes between 8 and 5 mya. • Larger than those of other hominoids and have more capacity for high-level thought. • Faces are thinner and flatter • Teeth are smaller • Longer thumbs and more flexible wrists (inc. manual dexterity)

WHAT STRUCTURES SUPPORT UPRIGHT WALKING? Bipedal- Walk upright on two legs * notice the shape of the spine , arms, pelvis, and legs. Why did hominins become bipedal? • Scientist suggest this was an adaptation to the new savanna environment. Individuals now could hold thing in their arms and travel longer distances and reach food better.

HUMAN ANCESTRY

THE HOMO GENUS • The genus Homo includes all humans living and extinct • Members of this genus first appeared in Africa between 3 and 2. 5 mya. • Scientist think they evolved from an australopithecine ancestor. • Homo species had bigger brains than australopithecines along with • bigger skeletons • Flatter faces • smaller teeth. Homo was the first genus to • Control fire • Use stone tools • Develop language and culture.

HOW DID HOMO HABILIS DIFFER FROM ITS ANCESTORS? • Was the first homo species for which fossils exist. • Means “handy man” • They used stone tools. • Homo traits of H. habilis included • Larger brains • Smaller brow and jaw • Flatter face • Human like teeth • Like its australopithecine ancestors it was small, had long arms, and could climb trees. Another species Homo Rudolfensis, might have lived at the same time. *however few fossils of this species exist and they are uncertain how this species is related to the homo line.

*This species only existed briefly in the fossil record. WHY IS HOMO ERGASTER IMPORTANT? Tools • It had a large brain than H. Habilis and was • Taller • Lighter • had longer legs and shorter arms • Scientist believe that H. Ergaster had the first human like nose (nostrils facing downward) • H. Ergaster made hand axes and other tools • Might have been a hunter or a scavenger *Tools might have been used to scrape meat off bones. Migration • H. Ergaster appeared to be the first African Homo species to migrate to Asia and Europe ( maybe following migrating animals) • Forms of H. Ergaster in Erope and Asia are called Homo Erectus.

WHAT SKILLS DID HOMO ERECTUS HAVE? *In Europe and Asia this species evolved from H. Ergaster. This species included “Java Man” discovered in Indonesia, and “Peking Man” discovered in China. This species adapted to many environments. Erectus as taller than habilis Had a bigger brain and more human like teeth Java man Featured a longer skull, low forehead, and a thick brow ridge. Made advanced tools, used fire, and lived in caves. Peking man

WHAT IS THE SIGNIFICANCE OF HOMO FLORESIENSIS? Scientist believe that H. Erectus went extinct about 400, 000 years ago. * fossils discovered in Indonesia suggest otherwise. (2004) This species, called H. floresiensis (flor eh see En sus) descended from H. erectus or another hominin. Existed till about 12, 000 years ago. Nicknamed “ the hobbit” H. Floresiensis was only about 1 m tall. *basic stone tools was found with its fossils

WHAT TRAITS DID HOMO HEIDELBERGENSIS DISPLAY? Transition from H. ergaster to modern humans occurred gradually. Some fossils display a mix of traits of H. ergaster and modern day humans. * scienctist classify these as Homo Heidelbergensis , others place them in a broad category called Homo sapiens. These humans had larger brains and thinner bones than H. ergaster, but still had think brow ridges and small chins.

ARE NEANDERTHALS OUR ANCESTORS? • Likey evolved from H. erectus or a homo species of the transitional period. • Lived about 30, 000 years ago. • They were larger than humans and had large brains • Had thick skulls and brow ridges, large noses, and heavy muscles attached to their thick bones. • Lived near the end of the Pleistocene ice age. • Hunted, used fire, and made complex shelters for themselves. • Evidence shows that they cared for their sick and buried their dead. • Some evidence suggest that Neanderthals overlapped with modern humans. • DNA tests on fossil bones show that Neanderthals were not part of the human gene pool. They actually were not part of the human gene pool at all and were an entirely different species. *Neanderthals (H. Neanderthalensis) were a species that only evolved in Europe and Asia.

EMERGENCE OF MODERN HUMANS

HOMO SAPIENS Characteristi cs: • Thinner skeletons ( more slender appearance) • Rounder skulls • Smaller faces (w/ obvious chin) • First appeared in what is now Ethiopia about 195, 000 millions of years ago. • Early members of this species chips stones to make hand axes and other tools.

WHAT IS THE “OUT OF AFRICA” HYPOTHESIS • ? Many hominin species overlapped until about 30, 000 years ago. Then, only modern humans remained. • The out of Africa hypothesis suggest that humans evolved only once, in Africa, and then migrated to all the parts of the world, replacing other hominins.

HOW DID DNA SUPPORT THIS HYPOTHESIS ? • Mitochondrial DNA analysis of today’s humans supported this hypothesis. • As a result, scientist reasoned that populations with the most variation in this DNA must have exists the longest time. • The widest variation was found among Africans. • Mitochondrial DNA is only inherited from the mother. • Therefore, this analysis suggest that H. Sapiens emerged in Africa about 200, 000 years ago from a hypothetical “mitochondrial eve” *Mitochondrial DNA changes very little over time.

WHAT EVIDENCE OF HUMAN CULTURE ? • Unlike Neanderthals, modern APPEARED humans expressed themselves using symbols and art. • They drew on cave walls and decorated objects • Developed complex tools and weapons. • They were the first to fish, make clothes, and raise animals. • These expressions marked the first fully modern humans. *some people consider Cro-Magnons to be the first hunter-gatherers.