ANT101 Lecture 13: Primate Origins

Overview of Primate Evolution

• Complexity of Primate Evolution

• Primate evolution reflects a complex interplay between environmental changes and evolutionary adaptations.

• Key Concepts in Primate Paleontology

1. We’re Probably Here Because Dinosaurs Are Not

   • Primates are part of the evolution of placental mammals, which became the dominant mammal type after the extinction of dinosaurs.

2. Different Ways to Calculate the Timing of Splits

   • Divergence estimates can be derived from:
   • Fossil Record: Physical remains of primates.
   • Genetic Data: Employing a molecular clock to calculate divergence times through genetic comparisons.

3. Fossil Data Limitations

   • Many fossil primates known only through dental remains (e.g., "dental apes"). Gaps exist in the fossil record.
   • It is essential to compare morphologies of fossils with living species to trace back evolutionary paths.

4. Uncertain Origins of Some Primate Types

   • Primate evolution spanned the last 65 million years with geographical changes affecting dispersion and evolution.

5. Unresolved Questions on Primate Emergence

   • Several hypotheses exist regarding primate emergence:
   • Visual Predation Hypothesis: Suggests adaptations for hunting in trees.
   • Angiosperm Radiation Hypothesis: Proposes that fruit consumption drove primate evolution.
   • Arboreal Hypothesis: Adaptations for life in trees contributed to their evolution.

Timeline of Primate Evolution

• Paleocene to Pliocene Timeline:

• Paleocene/Eocene: Earliest primates appear.

• Oligocene: First anthropoids emerge.

• Miocene: Apes become prominent.

• Pliocene: Hominins evolve.

• Plesiadapiforms (Paleocene)

• Observed traits suggest they are potential ancestors to modern primates.

• Characterized by a small, insectivorous morphology, which varies from later primate forms.

• Euprimates (Eocene)

• Three primary forms:

  1. Adapoids: Resemble lemurs; medium-sized with a folivorous diet.
  2. Omomyoids: Resemble tarsiers; smaller and insectivorous.
  3. Anthropoids: Ancestors to modern monkeys, apes, and humans; contested origin locations include North Africa and East/Southeast Asia.

• Miocene Era: Known as the "Planet of the Apes"

• Significant period of ape evolution, characterized by diverse adaptations and migrations.

• Early Miocene (24-16 mya): New varieties of hominoids arise.

• Late Miocene (17-5 mya): Discussions on the evolutionary path of Great Apes, likely based in Africa.

• Notable Species in Late Miocene:

• Pierolapithecus catalaunicus: An important discovery from Spain, shedding light on early great ape evolution.

• Sivapithecus: From Pakistan, likely ancestral to orangutans.

• Gigantopithecus: Large jaws suited for bamboo; fossils primarily consist of teeth and jaws.

• Oreopithecus: Specialized dentition indicating adaptations to swampy forests, possibly bipedal.

Conclusion

• Exam preparation will cover topics from the evolution of primates and their origins to key species and evolutionary milestones. Next class: Lecture 14 will focus on early hominins, ensuring a transition into the study of human evolution.