11u bio 01

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Evidence of Evolution: The Fossil Record

Transcript of 11u bio 01

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Evidence of Evolution:The Fossil Record

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The Fossil Record

Fossils are the preserved remains of prehistoric organisms.

Paleontology is the study of fossils.

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The Fossil Record

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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.

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The

Foss

il Re

cord

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The Fossil Record

Fossils may be used to determine information about species:

SizeWeightAgeLocationMigrationCause of extinctionDietCommon origins

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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.

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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.

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Transitional Fossils

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Transitional Fossils

Archaeopteryx

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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

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

Transitional Fossils

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Transitional Fossils

Tiktaalik

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Transitional Fossils

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How is the Fossil Record Evidence of Evolution?