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Human Evolutionary Development

Explore the fascinating journey of human evolution from the Eocene to Miocene epochs. The Eocene epoch (55-35 million years ago) saw the emergence of primitive primates like adapids and omomyids, while the Oligocene (35-25 million years ago) introduced early anthropoids such as Aegyptopithecus, a crucial link to modern monkeys. The Miocene epoch (25-5 million years ago), known as the "Golden Age of Apes," revealed significant hominoid radiations, notably the dryopiths and ramapiths. This overview highlights key genera and evolutionary transitions essential for understanding our ancestral lineage.

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Human Evolutionary Development

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  1. Human Evolutionary Development Eocene Epoch Oligocene Epoch Miocene Epoch

  2. Geologic Time & Human Evolution

  3. The Eocene epoch (55-35 mya) • Eocene warmest epoch of Cenozoic • NW Tenn., trop. rain forest, like Panama • First appearance of many modern orders of mammals • As mentioned, rodents • First bats, whales, modern ungulates and carnivores • Most important for us, the first P.O.M.A. • Primates of Modern Aspect • Two major groups: the adapids and omomyids • Both groups at the most primitive grade of adaptation

  4. The Adapids • First appear in early Eocene (50-55 mya) • Possibly in Asia in late Eocene • Found in both Europe and N. America • Early forms more numerous in Europe • Three important genera: • Cantius - earliest adapid • Only early Eocene genus from N. Am. & Eur. • Adapis - lemur-sized European form • Named & described by Cuvier (1821) • Notharctus - lemur-sized American form • Very lemur like

  5. The Omomyids • First appear in early Eocene (50-55 mya) • Found in Europe, N. America and Asia • Early forms more numerous in N. America • Important genera: • Teilhardina - earliest omomyid • From Belgium • Rooneyia - from late Eocene of N. America • they were very Tarsier or galago like

  6. Adapids vs. Omomyids

  7. The big question: Which group gave rise to the Anthropoids (Human and Great Ape Line)? Most fossil features point to the adapids Omomyids are good ancestors for tarsiers

  8. The Oligocene epoch (35-25 mya) - the first Anthropoids • The Fayum depression - Egypt, 60 mi. SW of Cairo • Early Oligocene (ca. 33 mya) 2 genera: • Apidium - squirrel-sized arboreal quadruped • Dental formula: 2-1-3-3 • Could be ancestor to both N.W. and O.W. • Aegyptopithecus - most important of Fayum finds • Dental formula: 2-1-2-3 • relatively large brain • Large bodied, ~12 lbs. on average • Substantial canine sexual dimorphism • Heavily-muscled, arboreal quadruped

  9. Aegyptopithecus

  10. Aegyptopithecus Reconstruction

  11. Old and New World Monkeys • Aegyptopithecus is best candidate for ancestral Old World Monkeys • Adaptation: like modern monkeys • What about the New World Monkeys? • Earliest fossil evidence from Bolivian Oligocene • Geologically same time as Fayum, ~33 mya

  12. Miocene Primate Evolution • The Miocene epoch (25-5 mya) - "The Golden Age of Apes" • Two major hominoid radiations • The dryopiths - Early to Middle Miocene (25-15 mya) • The ramapiths - Middle to Late Miocene (15-5 mya)

  13. The Dryopiths • Distribution (geographic and temporal) • Most forms from E. Africa • Some Mid-Miocene forms from Europe • Important genera • Proconsul - Early Miocene, E. Africa • Dryopithecus - Mid-Miocene, W. Europe • Morphology • Cranial features • Generalized • No major chewing specializations • Post-cranial ("below the head") features • Body size: monkey to _ gorilla-sized • Limb proportions - monkey-like • Fore-limbs not elongate • relatively short fingers & toes

  14. Dryopithecus

  15. Dryopithecines Reconstruction

  16. The Ramapiths • Distribution (geographic and temporal) • Most widespread hominoids ever (until us) • Turkey, Hungary, Greece, Pakistan (14-8 mya) • Later in China and mainland SE Asia (~8-0.5 mya) • Ancestors? • Probably a Middle Miocene, E. African form • Kenyapithecus: a good ancestor, ~14 mya • big powerful jaws • thick molar enamel • Most important genus • Sivapithecus (includes Ramapithecus)

  17. General Ramapith Morphology • Dentition similar to Dryopiths • One major dental character is thick molar enamel • Cranial features • More ape-like, chewing specializations • Post-cranial features • Not much evidence; seemingly more ape-like • More mobile shoulder joint • Possibly more terrestrial than Dryopiths

  18. Specific Sivapithecus Morphology • "What great ape would it resemble?" • Later Asian forms • Cranial features mirror Orangutan • Sloping lower face/jaw • It's best interpreted as ancestor of Pongo (Orangutan)

  19. Sivapithecus

  20. One other interesting ramapith genus: Gigantopithecus • Found in Pakistan and China • Dates to 9-0.5 mya, latest surviving Ramapith • Huge jaws and teeth; only parts found • May have been 6-9 ft. tall, >600 lbs! • What caused its extinction? • Maybe early humans • More mundane: Giant Panda • Same niche, large-bodied bamboo eater • Maybe NOT extinct! • Abominable Snowman & Sasquatch ???

  21. Gigantopithecus

  22. Last Common Ancestor? • Unable to determine exact specimen as yet. • Molecular data suggests split occurred between 6 and 5 million years ago. • Extensive genetic diversity in hominoids during the Miocene.

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