PE3 Oligocene

Summary

The Oligocene epoch marked a significant era in primate evolution, with the emergence of the first monkeys, or anthropoids. As Earth's climate cooled due to continental drift affecting ocean currents, new habitats and selective pressures led to the development of these primates. Fossil evidence from Fayum, Egypt, reveals the earliest monkeys, the Oligopithicids, dating back 35 million years. These primates dispersed globally, with some, the Parapithecids, migrating to South America to become New World monkeys, while others evolved into Old World monkeys, apes, and humans. Dental formulas differentiate these groups, with 2-1-3-3 for New World monkeys and 2-1-2-3 for Catarrhines, including humans.

Takeaways

• 📅 The Oligocene epoch saw rapid development of new primate adaptations and the first appearance of monkeys.
• 🌍 The Earth's climate changed dramatically during the Oligocene due to continental drift affecting ocean currents.
• ❄️ Cooling of the Earth during the Oligocene led to new habitats and natural selective pressures, resulting in new adaptations.
• 🐒 Monkeys, or anthropoids, emerged during the Oligocene and replaced many prosimians.
• 🦴 Fossil evidence from the Fayum region in Egypt shows the earliest monkeys appeared around 35 million years ago.
• 🌊 Monkeys rapidly dispersed across the Old World and to South America within 10 million years of their emergence.
• 🚢 Some Oligopithicids rafted across the Atlantic Ocean to South America, evolving into Platyrrhines, or New World monkeys.
• 🦍 Most Oligopithicids remained in Africa and evolved into Propliopithecids, leading to Old World monkeys, apes, and humans.
• 🔬 Aegyptopithecus, dating to about 30 million years ago, is the earliest example of a Catarrhine with a 2-1-2-3 dental formula.
• 🦷 New World monkeys retained the primitive 2-1-3-3 dental formula, while Old World monkeys, apes, and humans have the derived 2-1-2-3 dental formula.

Q & A

What significant primate adaptation emerged during the Oligocene epoch?

The first monkeys, or anthropoids, emerged during the Oligocene epoch.

How did continental drift impact the Earth's climate during the Oligocene?

Continental drift altered the distribution of ocean currents, which affected the Earth's climate by redistributing heat and cold, leading to a cooler global climate.

What was the impact of the Oligocene climate change on land habitats and primate evolution?

The cooler climate during the Oligocene changed land habitats, leading to new environmental pressures and the emergence of new primate adaptations, including the first monkeys.

Where is one of the best places to find fossil primates from the Oligocene period?

One of the best places to find fossil primates from the Oligocene period is the Fayum region in Egypt.

What does the fossil record from Fayum tell us about primate evolution during the Oligocene?

The Fayum fossil record shows that monkeys first appeared around 35 million years ago and that they quickly dispersed to different parts of the world, including South America.

What are Parapithecids, and what is their significance in primate evolution?

Parapithecids are an early group of monkeys that migrated to the Americas and evolved into the modern New World monkeys (Platyrrhines) found in Central and South America today.

What distinguishes Platyrrhines from other primates?

Platyrrhines, or New World monkeys, are distinguished by their primitive dental formula of 2-1-3-3.

Who were the Propliopithecids, and what did they evolve into?

Propliopithecids were a group of early monkeys that stayed in the Old World and eventually evolved into Old World monkeys, apes, and humans.

What is the significance of Aegyptopithecus in primate evolution?

Aegyptopithecus, dating to about 30 million years ago, is the earliest example of a Catarrhine monkey with the derived dental formula of 2-1-2-3, indicating a different evolutionary branch from New World monkeys.

How do the dental formulas of New World and Old World monkeys differ?

New World monkeys (Platyrrhines) have a primitive dental formula of 2-1-3-3, while Old World monkeys, apes, and humans (Catarrhines) have a derived dental formula of 2-1-2-3.