Ruddy mobile sex cam free - Fossil dating methods ppt

New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.Darwin and his contemporaries could never have imagined the improvements in resolution of stratigraphy that have come since 1859, nor guessed what fossils were to be found in the southern continents, nor predicted the huge increase in the number of amateur and professional paleontologists worldwide.

fossil dating methods ppt-51

Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation.

Index fossils are fossils that are known to only occur within a very specific age range.

The age of the fossil must be determined so it can be compared to other fossil species from the same time period.

Understanding the ages of related fossil species helps scientists piece together the evolutionary history of a group of organisms.

The Wheeler Formation has been previously dated to approximately 507 million year old, so we know the trilobite is also about 507 million years old.

But, how can we determine how old a rock formation is, if it hasn’t previously been dated?

Despite seeming like a relatively stable place, the Earth's surface has changed dramatically over the past 4.6 billion years.

Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.

Early geologists, in the 1700s and 1800s, noticed how fossils seemed to occur in sequences: certain assemblages of fossils were always found below other assemblages. Since 1859, paleontologists, or fossil experts, have searched the world for fossils.

In the past 150 years they have not found any fossils that Darwin would not have expected.

Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.

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