11u bio 01

Evidence of Evolution:The Fossil Record

The Fossil Record

Fossils are the preserved remains of prehistoric organisms.

Paleontology is the study of fossils.

The Fossil Record

The Fossil Record

Layers of sedimentary rock contain fossils.

New layers cover older ones, creating a record over time.

When fossils are arrayed in the order of their age, a progressive series of changes are seen.

The younger fossils are more similar to existing species than older ones.

The

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The Fossil Record

Fossils may be used to determine information about species:

SizeWeightAgeLocationMigrationCause of extinctionDietCommon origins

The Fossil Record

The Fossil record is incomplete and has many gaps.

Reasons:Species with delicate bodies don’t fossilize.

Species may not have lived in conditions that allow it to fossilize.

Fossils haven't been found.

Transitional Fossils

A transitional fossil is one that represents characteristics between groups of organisms. (the missing link)

It provides a link between past and present species.

Transitional Fossils

Transitional Fossils

Archaeopteryx

Transitional Fossils

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Assumption:Land vertebrates evolved from lobed-finned fishObservations:The first fossils of lobe-finned fish: 390 MYA.The earliest fossils of land vertebrates: 360 MYA.Prediction:The transition to land occurred 390 – 360 MYA.

Transitional Fossils: Tiktaalik

Shrubin discovers Fishapod!Four limbs with webbed fins and sturdy wrist bones Neck and shouldersThick ribsFlattened skull

Transitional Fossils

Transitional Fossils

Tiktaalik

Transitional Fossils

How is the Fossil Record Evidence of Evolution?