Fossil calibration

Definition

Fossil calibration is a method used in paleontology and phylogenetics to assign absolute ages to branches of a phylogenetic tree based on the ages of fossils. This technique helps researchers integrate fossil evidence with molecular data to establish timelines for evolutionary events, which is crucial for understanding the history of life on Earth and its ecological contexts.

5 Must Know Facts For Your Next Test

1. Fossil calibration allows scientists to estimate the timing of evolutionary divergences, improving the accuracy of phylogenetic trees.
2. This technique often relies on well-dated fossil specimens, which can provide a timeframe for the appearance of certain lineages.
3. Integrating fossil data with molecular data enhances the reliability of evolutionary timelines by bridging gaps between genetic information and actual historical records.
4. Fossil calibration can reveal discrepancies between molecular clock estimates and fossil records, prompting further investigation into evolutionary processes.
5. The use of fossil calibration has become increasingly important as researchers work to understand past climate changes and their impacts on biodiversity.

Review Questions

• How does fossil calibration improve the accuracy of phylogenetic trees in relation to evolutionary timelines?
  • Fossil calibration enhances the accuracy of phylogenetic trees by assigning absolute ages to different branches based on fossil evidence. This method allows scientists to integrate fossil data with molecular information, which helps in estimating when specific evolutionary divergences occurred. By providing a chronological framework, fossil calibration assists in creating more reliable representations of evolutionary relationships and timelines.
• Discuss the role of well-dated fossils in the process of fossil calibration and their significance in understanding evolutionary events.
  • Well-dated fossils are essential for fossil calibration because they serve as reference points that help establish absolute dates for branches in a phylogenetic tree. These fossils provide critical information about when certain species appeared and can indicate the timing of diversification events. Their significance lies in their ability to bridge the gap between genetic data and geological time, enabling researchers to construct a more accurate timeline of life's evolution on Earth.
• Evaluate how integrating fossil data with molecular data through fossil calibration can influence our understanding of past climate changes and biodiversity.
  • Integrating fossil data with molecular data through fossil calibration offers valuable insights into how past climate changes impacted biodiversity. By establishing a timeline for evolutionary events, researchers can correlate shifts in species composition with historical climate variations. This evaluation helps illuminate patterns of extinction and adaptation, revealing how organisms responded to environmental pressures over time, ultimately enriching our understanding of resilience and vulnerability within ecosystems.

Related terms

Phylogenetic tree: A diagram that represents the evolutionary relationships among various biological species based on similarities and differences in their physical or genetic characteristics.

Molecular clock: A technique that uses the mutation rates of biomolecules to deduce the time in prehistory when two or more life forms diverged.

Biostratigraphy:

The branch of stratigraphy that uses fossil organisms to establish relative ages of rock layers and to correlate them across different geographic locations.