Understanding primate evolution requires placing fossils in the immense timeline of Earth’s history. This lesson introduces geological time, explains what fossils are, and shows how researchers estimate fossil ages.
Deep time refers to the vast timescale of Earth’s history, extending across billions of years. Geologists organize this history into units such as eras and epochs. Eras are generally distinguished in part by the fossil life forms found in their rocks.
All flashcards
What is deep time?
Deep time is the vast span of Earth's history, extending across billions of years. Geologists organize it into eras and smaller units such as epochs.
Why is the fossil record incomplete?
Most organisms do not become fossils because remains usually decompose. Preservation and later discovery are uncommon, so only a small fraction of past life is represented.
What is the difference between relative and absolute dating?
Relative dating establishes whether a specimen is older or younger than another. Absolute dating estimates its age in years, usually within a range.
What is stratigraphy?
Stratigraphy is the study of successive soil or rock layers. In an undisturbed sequence, lower layers are generally older than those above them.
How does thermoluminescence dating work?
A high-temperature event releases accumulated energy in a material. Energy accumulates again afterward, and measuring it can help estimate the time since the heating event.
Quiz questions
Which dental traits distinguish the early primate fossil Purgatorius in the account of its discovery?Answer: An elongated last lower molar and an enlarged upper central incisor.
What is the postorbital bar described in Eocene primates?Answer: A fully bony ring surrounding the eye orbit.
In a primate dental formula of 2.1.2.3, what does the final 3 represent?Answer: Three molars in each jaw quadrant.
What locomotor pattern is suggested by Proconsul's anatomy?Answer: It likely moved mainly on all four limbs.
What does the thick dental enamel of Sivapithecus suggest about its diet?Answer: It regularly consumed hard foods.
Based on Introduction to Anthropology by Jennifer Hasty, David G. Lewis, Marjorie M. Snipes (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.