HISTORY OF EVOLUTIONARY

THOUGHT

Unit Objective #1

I CAN COMMUNICATE SCIENTIFIC

INFORMATION THAT COMMON ANCESTRY

AND BIOLOGICAL EVOLUTION ARE SUPPORTED BY

MULTIPLE LINES OF EMPIRICAL EVIDENCE.

LIFE CHANGES OVER TIME

Earth formed 4.6 byaLife began 3.5 byaMost life as we know it

has been here a relatively short amount of time on the geologic scale (~600 million years)

What is a fossil: Preserved remains or traces of an organism from the past

How to make a fossil: Organism lives Organism dies Immediately, remains are buried to prevent rapid

decomposition Slowly remains (usually hard parts) are replaced w/ another

material

FOSSILS: OUR CLUES TO LIFE’S HISTORY

Layers of the Earth show a consistently aging planetOrganisms living during the past have been preservedNearly all fossilized species are extinctTherefore: life evolves as the environment changes

BIG PICTURE

Scientists have questioned how life came to be since BC

Scientists have formed theories for evolution for centuries

The widely accepted theory of evolution by natural selection explains…

BIG PICTURE

PAST: ORGANISMS HAVE GONE EXTINCT

PRESENT: DIVERSITY OF LIFE ON EARTH

FUTURE: SPECIES CONTINUE TO EVOLVE