11u bio 01
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Transcript of 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
Foss
il Re
cord
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?