1. African forms (23 14 mya)

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2 1. African forms (23 14 mya) These hominoids are, in many ways, primitive or ancestral Proconsul has monkey and ape characteristics 2. European forms (16 11 mya) Most are quite derived (changed from ancestral form) Dryopithecus Ouranopithecus 3. Asian forms (16 7 mya) The largest and most varied group - most are highly derived (changed from ancestral form) Sivapithecus

3 Ape like features Did not have tail Shoulders and elbows like apes Skull is large relative to overall size Teeth like hominoid, shape of lower premolar Monkey-like features Limb proportions more like monkey s, arms and legs same size mya - Classified as an early hominoid because overall structure is more like an ape than a monkey, but still retains primitive traits or monkey-like features.

4 Dates back early Miocene 12 mya First species found in 1856 in France Ape and monkey characteristics

5 Dates back to early Miocene 9 mya Ouranopithecus macedoniensis - Greece and Bulgaria Ouranopithecus turkae - Turkey

6 Date back to 12.5 mya Previously known as Ramapithecus Pakistan, 1970s Parabolic-ish? dental arcade Thick enamel Was thought to be possible hominin, but debated? We later learned: ASIAN apes also have thick enamel Only African apes have thin enamel Ramapithecus, renamed Sivapithecus Is orangutan (not human) ancestor

7 Shape of skull, teeth, and oval shaped eye sockets and eyes set close together are similar to modern-day orangutans Sivapithecus (L) modern orangutan (R)

8 Comparison of a modern chimpanzee (left), Sivapithecus (middle), and a modern orangutan (right) Both Sivapithecus and the orangutan exhibit a dished face, broad cheekbones, and projecting upper jaw and incisors

9 Miocene Apes in China 1. Lufengpithecus (genus) Miocene ape from China Find all the way through Pliocene (1 mya) Fossil is squashed flat Oldest consists of single mandible (jaw)

10 Miocene Apes in China 2. Gigantopithecus 2 species: A)Gigantopithecus bilaspurensis 8-10 mya India/China B) Gigantopithecus blacki

11 Gigantopithecus blacki Largest primate that ever lived Estimated to be ~600 lbs Separated from G. bilaspurensis by 7 million years ago 8 mya 100 kya - Spanned the Miocene into the Pliocene all the way to the Pleistocene in China, India, Vietnam Pictured: Far left: G. blacki Middle: Modern Gorilla Far Right: Modern Human

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13 Very few hominoid species (apes and humans) remain Even if Miocene fossils have some characteristics that resemble living orangutans or other apes, we cannot assume the fossil forms are closely related to living species We should assume that most lines vanish without descendants We can, however, note possibilities and patterns of change over time New fossil finds are constantly giving us more information about these early hominins

14 Date Hominoid Significance 55 8 mya Adapidae (Adapids) Eocene - Lemur-like, but NOT lemurs, NOT lemur ancestors 1 lb+ (but not huge); Diurnal? Binocular vision, Nails, Increasing brain size mya Omomyidae (Omomyids) Eocene - Tarsier-like 0.5 lbs; Smaller, but overlap with Adapids Nocturnal? Insectivorous mya Apidium Oligocene Primates from Fayum Primitive dental arrangement suggests near or before evolutionary divergence of Old and New World anthropoids Small, squirrel-like, arboreal quadruped, fruit and seed eating, adept at leaping and springing mya Aegyptopithecus Oligocene - Largest of Fayum anthropoids, about the size of a modern howler monkey (13-18 lbs) Short-limbed, slow-moving mya Proconsul heseloni Miocene - Nicknamed the Dental Ape. Classified as an early hominoid because overall structure is more like an ape than a monkey, but still retains primitive traits or monkey-like features 12 mya Dryopithecus Miocene - Ape and monkey characteristics 9 mya Ouranopithecus Miocene Evidence that they may be closely related to Dryopithecus 12.5 mya Sivapithecus Miocene - Previously known as Ramapithecus Was thought to be possible hominin ancestor, but later discovered to be orangutan ancestor 23 1 mya Lufengpithecus Miocene ape from China. Found right into the Pliocene 9 mya 100 kya Gigantopithecus blacki Largest primate that ever lived - Estimated to be ~600 lbs Spanned the Miocene into the Pliocene all the way to the Pleistocene in China, India, Vietnam

15 First bipedal hominins appeared in Africa 6-7 mya Marks divergence of hominins and African apes Derived trait bipedal Ancestral traits - apelike teeth, ape-sized brains

16 East African sites along the Great Rift Valley where more than 2,000 hominin fossils have been found

17 The earliest possible hominins based on derived trait of bipedalism Sahelanthropus Tchadensis Orrorin tugenensis Ardipithecus ramidus

18 Three possible Pre-Australopithecine candidates Sahelanthropus (oldest - 7 Mya) found 2002 Position of foreman magnum suggests bipedalism Orrorin tugenesis (6 Mya) found 2001 Fossil evidence indicates that Orrorin was possibly capable of bipedalism, but not necessarily that Orrorin routinely walked bipedal Ardipithecus ramidus ( Mya) found 1995 Toe bone indicates evidence of bipedalism All three are more apelike than human, but possible evidence of bipedalism places them on human ancestral line

19 The earliest bipedal hominins earliest possible human ancestors. Living at about the same time. Sahelanthropus tchadensis was found in Chad. Orrorin and Ardipithecus were found in Kenya and Ethiopia. (Scientific American, 8/25/2003)

20 Earliest hominin fossil found in Chad 1600 miles from Eastern Rift Valley Bipedal? Foramen magnum says yes Has unusual combination of traits: Ancestral apelike features Small braincase (350 cc) Massive build Huge brow ridges supraorbital tori Sagittal Crest Derived features (more human-like) Smallish vertical face teeth very unlike that of apes face not protruding reduced, non-honing canine teeth

21 Compare an Eocene primate and modern human skull The position of the foramen magnum indicates the angle of the spinal column to the head and indicates whether the body is habitually horizontal (quadrupedal like most primates) or vertical (bipedal like humans)

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23 6 mya Found 2001 Western Kenya Fragmentary Bipedal femur, non-honing canines Curved fingers (ape-like) Smaller teeth than australopithecines Thin enamel

24 Ardipithecus (2 types) A) Ardipithecus kadabba B) Ardipithecus ramidus Ardi mya Middle Awash, Ethiopia ~ 4 ft tall, 110 pounds Non-honing dentition Primitive polishing Only hominin with thin enamel Brain size: cc

25 Ardipithecus ramidus Ardi foramen magnum indicates bipedalism mya ape-like dentition bipedal locomotion overall hominid-like skeleton small cheek teeth with thin enamel and large canines arm bones are hominin-like

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27 Taphonomy is the study of how bones and other materials come to be buried in the earth and preserved as fossils It is the study of the process of burial, decay, and fossilization

28 What is Required for Fossilization? 1. Possess hard parts bone, teeth, shell 2. Get buried rapidly to avoid scavengers and/or exposure to elements that speed decay 3. Become preserved over the long term little to no disturbance 4. Avoid dissolution into other matter 5. Become exposed over the long term - Tectonic uplift essential to expose the long preserved fossil 6. Get discovered!

29 After millions of years, most organic matter is either destroyed or broken. While there are forms of fossilization that will provide unaltered organic material, most fossils found are changed from their original composition. Permineralization Mold Replacement Recrystallization Carbonization Desiccation Amber

30 Permineralization occurs when organic material, such as bones or wood, absorb and hold minerals before decaying themselves. This results in a drastically different and more stable composition of fossil than the original organic material. These are the kinds of fossils people are most familiar with, largely due to the fact that most dinosaur bones are a result of Permineralization. Petrified Wood is another great example of Permineralization.

31 A mold occurs when organic material is buried by sediment. Eventually, the organic material decays, leaving a trace outline of the original organism. In this manner, no organic material remains. These also include fossils of footprints or of textures from things such as feathers or leaves. Sometimes sediment inside a clam will fossilize, giving an imprint of the clam s insides. These are called Steinkerns.

32 Replacement fossilization is similar to Permineralization in that a foreign mineral assumes the shape of the organic material. However it is also similar to Mold fossilization in that the organic matter is already deteriorated. The result is a foreign mineral being molded into the shape of the original organism. Some of the most interesting examples involve metals such as iron pyrite replacing the form of an invertebrate s shell mold.

33 Recrystallization occurs when organic material isn t chemically stable enough after deposition to maintain it s composition. This is most often found amongst invertebrate shells, which will change from aragonite to calcite.

34 Carbonization occurs when enough pressure is placed upon organic material that the carbon is left behind in the rock. Examples are characteristically black and in the shape of the animal that was deposited.

35 Desiccation occurs when an animal dies in extremely dry and arid locations, such as deserts or some caves. Essentially, these conditions create an aseptic environment, where it is highly unlikely that it will be able to decay. These fossils are very rare, due to the fact that they require that the remains be undisturbed by scavengers and that the environmental factors leading to desiccation remain constant. Desiccation is almost identical to mummification, although it is conducted by natural conditions and are typically from further back in time.

36 Essentially, Amber is tree sap that has hardened after many millions of years. Occasionally, insects and small animals would manage to get themselves caught in the sap, and would be preserved in almost pristine condition. You may be familiar with this method of fossilization due to the movie Jurassic Park, where dinosaur DNA was extracted from parasitic insects trapped in Amber. In real life though, this is impossible, due to the fact that the half life of DNA is about 521 years.

37 This animal s bones still have traces of its original organic matter. Also, markings around it s body indicate that it at one point had fur. A. Carbonization and Recrystallization B. Permineralization and Mold C. Permineralization and Carbonization D. Replacement and Mold E. Desiccation and Carbonization

38 Relative dating methods tell you that something is older or younger than something else, usually gives a range of dates Chronometric (Absolute) dating methods are based on calendar years, gives specific dates

39 Stratigraphy based on the law of superposition, which states that a lower layer is older than a higher one Biostratigraphy based on regular changes seen in dentition and other anatomical structures in groups of pigs, rodents, and baboons Paleomagnetism based on the shifting of earth s geomagnetic pole; by examining magnetically charged particles Fluorine Dating Fluorine absorption dating is a method used to determine the amount of time an object has been underground. Fluorine absorption dating can be carried out based on the fact that groundwater contains fluoride ions. Items such as bone that are in the soil will absorb fluoride from the groundwater over time

40 Relative dating methods Stratigraphy The horse skulls on the left are arranged according to the dates of the geological strata/layer of earth.

41 Relative dating methods Stratigraphy Law of Superposition Defined: In an undisturbed series of sediments, the younger layers are on top of the oldest ones Sediments have constant layering and build up over time The oldest ones got laid down later in time The more recent ones were laid down subsequently

42 Relative dating methods Biostratigraphy Layers of the Earth Names each layer based on the organisms that are fossilized within. E.g. Miocene: 23-5 mya

43 Relative dating methods Paleomagnatism Certain minerals in rocks lock-in a record of the direction and intensity of the magnetic field when they form. Paleomagnetic studies of rocks and ocean sediment have demonstrated that the orientation of the earth's magnetic field has frequently alternated over geologic time. Periods of "normal" polarity (i.e., when the north-seeking end of the compass needle points toward the present north magnetic pole, as it does today) have alternated with periods of "reversed" polarity (when the north-seeking end of the compass needle points southward).

44 Fluorine Fluorine is an element that is found in most ground water around the world. It can be used as a relative dating technique. Skeletal remains buried in the earth are subject to a wide range of chemical changes. One of these changes can occur when ground water comes into contact with the remains. The ground water inundates the bone remains with a solution of minerals drawn from local soils. Fluorine dating is chiefly of value in determining whether bone implements or human skeletal remains found in association with other bones were buried at the same time. It was fluorine dating that was instrumental in the debunking of Piltdown Man.

45 The potential flaws in relative dating are obvious. Simply assuming that an object is older because it was found at a lower depth in the record is only subjective science. There are many instances of deep holes being dug for rubbish pits or to locate well water that protrude into the record of older strata injecting more modern material as they are filled in over time. Landslides and slips can completely change the topography of an entire site burying what was once on top by that which is much older, hence reversing the strata layers

46 Based on Radioactive decay Radiometric Dating Radioactive isotopes of certain elements are unstable and decay to form isotopic variants Decay rates follow a predictable mathematical pattern Accurate Geological Clock

47 K/Ar Method Potassium Argon method used to date materials in the 5-1 mya range Potassium-40 has a half life of 1.25 million years Potassium isotopes produce Argon-40 Cannot date organic material, but good for dating rock containing fossils By comparing the amount of K-40 to Ar-40 in the volcanic rock, the date that the rock formed can be determined

48 U/Pb Method Uranium lead (U Pb) dating is one of the oldest and most refined of the radiometric dating Uranium half life is 4.47 Billion years - Produces lead Good for dating very old rock materials 1 mya to 4.5 bya

49 Carbon-14 method Half life of carbon-14 is 5,730 years Used to date organic material extending back to 50,000 years

50 Fission Track Dating 238 U can decay by spontaneous fission Small tracks are created on crystals (zircon, apatite, titanite) and volcanic glass Track density is proportional to U-content and to time since the crystal formed Useful for dating volcanic rocks (>200 kyr) Problem: tracks can heal over time

51 Thermo-luminescence Detects the luminescence of heat released from stone materials once they have been struck or altered Good for dating stone tools and ceramic artifacts

52 Electron Spin Resonance (ESR) Measures number of electrons excited to higher energy levels by natural radiation & trapped at those levels, dates teeth & cave deposits from about 1000 ya to 1 mya

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