1. Primate Evolution

2. Today’s Objectives:
investigate and understand how primates have changed through time, including:
Examining fossil records
Recognizing how adaptations lead to natural selection

4. Primates are mammals that have:
Opposable thumbs
Large brain
Good, stereoscopic vision
Ability to brachiate
Flexible elbows for hand rotation
Grasping feet

5. Early Primates Appeared 60-65 million years ago Prosimian Anthropoids
Small bodies
Lemurs, Tarsiers
Anthropoids
Human-like primates
Evolved in Africa
Primates are remarkably recent animals.  Most species of living things had become extinct long before the first monkeys and their prosimian ancestors evolved.  While the Earth is about 4.55 billion years old and the first life dates to at least 3.5 billion years ago, the first primates did not appear until around 60 million years ago.  That was after the dinosaurs had become extinct.

6. Transitional primate-like creatures were evolving by the end of the Mesozoic Era (ca. 65 million years ago).   At that time, the world was very different from today.  The continents were in other locations and they had somewhat different shapes.  North America was still connected to Europe but not to South America.  India was not yet part of Asia but heading towards it.  Australia was close to Antarctica.  Most land masses had warm tropical or subtropical climates.

7. Small Insectivore from the end of the Mesozoic Era
The flora and fauna  at the end of the Mesozoic Era  would have seemed alien since most of the plants and animals that are familiar to us had not yet evolved.  Large reptiles were beginning to be replaced by mammals as the dominant large land animals.  Among the mammals, there were a few archaic egg-layers (monotremes) like the ancestors of the platypus and echidna.  There were larger numbers of pouched opossum-like mammals (marsupials).  The few placental mammals that existed at that time mainly consisted of the Insectivore ancestors of primates.  The large grass-eating placental mammals, such as cattle and wildebeest,  were absent as were the vast grasslands that would later develop.  Rodents and small-seed eating birds were also absent.  The great proliferation of flowering plants had not taken place yet, however, forests of broad-leafed trees were developing over much of the earth.
 Small Insectivore from the  end of the Mesozoic Era

8. Proto-primates
The first primate-like mammals, or proto-primates , were roughly similar to squirrels and tree shrews in size and appearance.  The existing, very fragmentary fossil evidence (mostly from North Africa) suggests that they were adapted to an arboreal  way of life in warm, moist climates.  They probably were equipped with relatively good eyesight as well as hands and feet with pads and claws for climbing.  These proto-primates will remain rather shadowy creatures for us until more fossil data becomes available.
Early primate-like mammals do not seem to have played an important role in the general transformation of terrestrial animal life immediately following the massive global extinctions of plants and animals that occurred approximately 65,000,000 years ago.  The most dramatic changes were brought about by the emergence of large grazing and browsing mammals with tough hoofs, grinding teeth, and digestive tracts specialized for the processing of grass, leaves, and other fibrous plant materials.  The evolution of these herbivorous mammals provided the opportunity for the evolution of the carnivorous  mammals specialized to eat them.  These new hunters and scavengers included the dogs, cats, and bears.  Adaptive radiation was resulting in the evolution of new species to fill expanding ecological niches, or food getting opportunities.  Most of these new animals were placental mammals.  With the exception of bats, none of them reached Australia and New Guinea.  This explains why they did not exist there until people brought them in recent times.  South America had also drifted away from Africa and was not connected to North America after 80,000,000 years ago.  However, around 20,000,000 years ago, South America reconnected with North America and placental mammals streamed in for the first time, resulting in the extinction of most of the existing marsupial fauna there.

9. Smilodectes (lemur-like family Adapidae from the Eocene Epoch)
Early Prosimians
The first primates may have evolved during the last part of the Paleocene Epoch .  These were members of the genus Altiatlasius .  Their bones have been found in 60,000,000 year old geological deposits in Morocco, but they probably lived in other areas at this time as well.  They looked different from the primates today.  They were still somewhat squirrel-like in size and appearance, but apparently they had grasping hands and feet that were increasingly more efficient in manipulating objects and climbing trees.  It is likely that they were developing effective stereoscopic vision.    
Smilodectes    (lemur-like family Adapidae    from the Eocene Epoch)  

10. The beginning of the Eocene Epoch  coincides with the appearance of early forms of most of the placental mammal orders that are present today.  Among them were primate species that somewhat resemble modern prosimians such as lemurs, lorises, and possibly tarsiers.  This was the epoch of maximum prosimian adaptive radiation.  There were at least 60 genera of them that were mostly in two families--the Adapidae (similar to lemurs and lorises) and the  Omomyidae  (possibly like galagos and tarsiers).  This is nearly four times greater prosimian diversity than today.  Eocene prosimians lived in North America, Europe, Africa, and Asia.  It was during this epoch that they reached the island of Madagascar.  The great diversity of Eocene prosimians was probably a consequence of the fact that they did not have competition from monkeys and apes since these latter more advanced primates had not yet evolved.

11. Early Monkeys and Apes
The Oligocene Epoch was largely a gap in the primate fossil record in most parts of the world.  This is especially true for prosimian fossils.  Most of what we know about them came from the Fayum  deposits in Western Egypt.  While this area is a desert today, million years ago (during the early and mid Oligocene) it was a tropical rainforest.  Other Oligocene deposits containing some fossil primate bones have been found in North and West Africa, the southern Arabian Peninsula, China, Southeast Asia, as well as North and South America.
Monkeys evolved from prosimians during the Oligocene or slightly earlier.  They were the first species of our suborder--the Anthropoidea .  Several genera of these early monkeys have been identified--Apidium  and Aegyptopithecus  are the most well known.  The former was about the size of a fat squirrel (2-3 pounds), while the latter  was the size of a large domestic cat (13-20 pounds).  Both were probably fruit and seed eating forest tree-dwellers.  Compared to the prosimians, these early monkeys had fewer teeth, less fox-like snouts, larger brains, and increasingly more forward-looking eyes. 
Due to the comparative scarcity of Oligocene Epoch prosimians, it is generally believed that the monkeys out-competed and replaced them in most environments at that time.  Supporting this hypothesis is the fact that modern prosimians either live in locations where monkeys and apes are absent or they are normally active only at nighttime when most of the larger, more intelligent primates are sleeping.

12. Great Rift Valley system (shown in green)   
Great Rift Valley system    (shown in green)  
The Oligocene was an epoch of major geological change with resulting regional climate shifts that likely affected the direction of evolution and altered fossil preservation conditions.  By the beginning of the Oligocene, North America and Europe drifted apart and became distinct continents.  The Great Rift Valley system of East Africa also was formed during the Oligocene along a 1200 mile long volcanically active fault zone between large tectonic plates.  

13. India Forcing up the Himalayas and the Tibetan Plateau
During the early Eocene Epoch, about 55,000,000 years ago, India finally crashed into Asia and began forcing up the Himalayan chain of mountains and the Tibetan Plateau beyond.   By the Oligocene, the progressive growth of this immense barrier very likely altered continental weather patterns significantly by blocking the summer monsoonal rains.  These and other major geological events during the Oligocene triggered global climatic changes.  The cooling and drying trend that had begun in the late Eocene Epoch accelerated, especially in the Northern Hemisphere.  A result was the general disappearance of primates from these northern areas.  However, global climates were still warmer than today.

15. Hominid Evolution Hominids developed 5-8 million yrs ago
Hominids are bipedal
First hominids were in
genus Australopithecus
“Lucy” most famous fossil hominid
More modern hominids were in genus Homo

16. More recent humans Homo sapiens (developed 400,000 years ago)
Neanderthals
Europe arrival (100,000 years ago)
Cro-Magnon
Europe arrival (40,000 years ago)
Americas arrival (12,000 years ago)
Humans (known taxonomically as Homo sapiens,[3][4] Latin for "wise man" or "knowing man")[5]are the only living species in the Homo genus. Anatomically modern humans originated in Africaabout 200,000 years ago, reaching full behavioral modernity around 50,000 years ago.[6]

17. A schematic showing the spreading of humans in history

18. The Spreading of early modern man (red) from Africa, based on genetic studies. 

19. Up to 37 500 YBP

20. Up to 35 000 YBP

21. Up to 32 500 YBP

22. Up to 30 000 YBP

23. To put Human History into prospective

24. The Earth forms and is bombarded by meteorites and comets.
130 million Years ago
As the continents drift toward their present positions, the earliest flowers evolve, and dinosaurs dominate the landscape. In the sea, bony fish diversify.
500 million Years ago
Fish-like vertebrates evolve. Invertebrates, such as trilobites, crinoids, brachiopids, and cephalopods, are common in the oceans.
248 million Years ago
Over 90% of marine life and 70% of terrestrial life go extinct during the Earth's largest mass extinction. Ammonites are among the survivors.
4 million Years ago
In Africa, an early hominid, affectionately named "Lucy" by scientists, lives. The ice ages begin, and many large mammals go extinct.
130,000 Years ago
Anatomically modern humans evolve. Seventy thousand years later, their descendents create cave paintings — early expressions of consciousness.
65 million Years ago
A massive asteroid hits the Yucatan Peninsula, and ammonites and non-avian dinosaurs go extinct. Birds and mammals are among the survivors.
555 million Years ago
Multi-cellular marine organisms are common. The diverse assortment of life includes bizarre-looking animals like Wiwaxia.
250 million Years ago
The supercontinent called Pangea forms. Conifer-like forests, reptiles, and synapsids (the ancestors of mammals) are common.
360 million Years ago
Four-limbed vertebrates move onto the land as seed plants and large forests appear. The Earth's oceans support vast reef systems.
450 million Years ago
Arthropods move onto the land. Their descendants evolve into scorpions, spiders, mites, and millipedes.
3.5 billion Years ago
Unicellular life evolves. Photosynthetic bacteria begin to release oxygen into the atmosphere.
420 million Years ago
Land plants evolve, drastically changing Earth's landscape and creating new habitats.
4.6 billion
The Earth forms and is bombarded by meteorites and comets.
3.8 billion Years ago
Replicating molecules (the precursors of DNA) form.
225 million Years ago
Dinosaurs and mammals evolve. Pangea has begun to break apart.
Years ago Event
130,000 Years ago
Anatomically modern humans evolve. Seventy thousand years later, their descendents create cave paintings — early expressions of consciousness.
4 million Years ago
In Africa, an early hominid, affectionately named "Lucy" by scientists, lives. The ice ages begin, and many large mammals go extinct.
65 million Years ago
A massive asteroid hits the Yucatan Peninsula, and ammonites and non-avian dinosaurs go extinct. Birds and mammals are among the survivors.
130 million Years ago
As the continents drift toward their present positions, the earliest flowers evolve, and dinosaurs dominate the landscape. In the sea, bony fish diversify.
225 million Years ago
Dinosaurs and mammals evolve. Pangea has begun to break apart.
248 million Years ago
Over 90% of marine life and 70% of terrestrial life go extinct during the Earth's largest mass extinction. Ammonites are among the survivors.
250 million Years ago
The supercontinent called Pangea forms. Conifer-like forests, reptiles, and synapsids (the ancestors of mammals) are common.
360 million Years ago
Four-limbed vertebrates move onto the land as seed plants and large forests appear. The Earth's oceans support vast reef systems.
420 million Years ago
Land plants evolve, drastically changing Earth's landscape and creating new habitats.
450 million Years ago
Arthropods move onto the land. Their descendants evolve into scorpions, spiders, mites, and millipedes.
500 million Years ago
Fish-like vertebrates evolve. Invertebrates, such as trilobites, crinoids, brachiopids, and cephalopods, are common in the oceans.
555 million Years ago
Multi-cellular marine organisms are common. The diverse assortment of life includes bizarre-looking animals like Wiwaxia.
3.5 billion Years ago
Unicellular life evolves. Photosynthetic bacteria begin to release oxygen into the atmosphere.
3.8 billion Years ago
Replicating molecules (the precursors of DNA) form.
4.6 billion Years ago
The Earth forms and is bombarded by meteorites and comets.