{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter 5 Apes and Other Ancestors.Prehominin Evolution

Chapter 5 Apes and Other Ancestors.Prehominin Evolution -...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 5 – Apes and Other Ancestors: Prehominin Evolution Dating Procedures - Fossilization occurs when dead organisms are covered with sediment at the bottom of a sea or lake or at the bend of a river - Fossils also accumulate in caves and sinkholes - Within geology, stratigraphy (sequence of rock layers formed over time) allows for relative dating of fossils, comparing them to the layers that they are buried in - This comparative method of dating also applies to faunal correlation , where a site can be dated by the similarity of surrounding fossils that have a known absolute date - Methods of absolute dating measure the age of a fossil using radioactive material - In addition to carbon 14, other methods are used for dating, including; 1. fission-track dating – dating rocks from tracks left by splitting uranium 238 atoms 2. thermoluminescence – dating pottery and stone tools by heating them to release electrons, which produce a measurable light 3. optically stimulated luminescence – same as thermoluminescence, but measures the release of electrons from sediments 4. paleomagnetism – measures the fossilized magnetism in a rock sample and matches it with a dated history of global magnetic reversals The Earliest Primates - The first primates appeared nearly 55 mya, during the Eocene epoch , some estimates date primates back to 82 mya during the Paleocene epoch - The first euprimates had grasping hands and feet, orbital convergence, and postorbital bars - The oldest known primates were the semiorder plesiadapiforms , resembling tree shrews - Plesiadapiforms were rodentlike, and unlike euprimates, they lacked postorbital bars and orbital convergence, had claws on semiprehensile digits, and had specialized front teeth - They were probably not ancestral to modern primates, but a sister group to euprimates, which gave rise to modern primates Undoubted Primate Fossils - Euprimates came into existence during the Eocene epoch, with sites in North America, Europe, and Asia - The suggestion that euprimates originated from African was based on the fossil Altiatlasius , but recent reanalysis suggest that it may be a plesiadapiform that dispersed
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 4

Chapter 5 Apes and Other Ancestors.Prehominin Evolution -...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online