I. What is Paleontology?

The study of past life.

I1. Paleontologist

□Paleontologist – scientist who studies fossils and plants from past life and other past ecosystems

□ Studies traces left behind by animals and piece together the conditions under which fossils were formed.

III. Uniformitarianism

□Uniformitarianism – the idea that the same geologic processes shaping the Earth today have been at work throughout Earth’s history.

□This takes a LONG time!

Extra Info!

James Hutton was the first to develop the idea of Uniformitarianism in 1788

His theory sparked a scientific debate by suggesting that Earth was much molder than previously thought!

Rocks record geological events and changing life forms of the past.

We have learned that Earth is much older than anyone had previously imagined

Continued

There are two ways that we can determine the age of a rock:

1. Relative Dating 2. Absolute Dating

IV. Relative Dating

Relative dating tells us the sequence in which events occurred, not how long ago they occurred.

Chronological order

- relational

a. Law of Superposition

The law of superposition states that in an undeformed, undisturbed

sequence of sedimentary rocks, each bed is older than the one above it and

younger than the one below it.

Undistrubed Rock Layer

Distrubed Rock Layer

b. Original Horizontality

The principle of original horizontality means that layers of sediment are

generally deposited in a horizontal position.

c. Index fossils

• Index fossils are used to determine approximate age. Index fossils are widespread geographically, are limited to a short span of geologic time, and occur in large numbers.

FOUND IN SEDIMENTARY ROCKS

Index Fossils

d. Geological Column

Geologic column is an ideal sequence of rock layers that

contains all the known fossils and rock formations on Earth arranged

from oldest to youngest.

Ticket out the Door!

What is Uniformitarianis

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