history of live on earth

Created by

Sabrina Alho

Cards (16)

Fossilization Process 
1. Death
2. Burial
3. Sedimentation
4. Mineralization
5. Preservation
6. Exposure
Death 
An organism dies and its remains settle in a sedimentary environment
Burial 
The remains are quickly buried by sediment, protecting them from scavengers and decay
Sedimentation 
Layers of sediment accumulate over time, increasing pressure on the buried remains
Mineralization 
Minerals in groundwater seep into the remains, replacing organic material and forming a rock-like fossil
Preservation 
The surrounding sediment hardens into rock, preserving the fossil within it
Exposure 
Geological processes, such as erosion, eventually expose the fossil at the surface
These steps outline the key stages in the fossilization process
Radiometric Dating
Definition: A method used to determine the age of rocks and fossils based on the decay rate of radioactive isotopes.
Process:
Measures the ratio of parent isotopes to daughter isotopes within a sample.
Uses the known half-life of the parent isotope to calculate the absolute age.
Common Isotopes: Carbon-14 (for dating recent organic remains), Uranium-238, Potassium-40.
Relative dating 
A method used to determine the relative age of rocks and fossils by comparing their positions within layers of sedimentary rock
Principles of relative dating
Law of Superposition
Principle of Original Horizontality
Principle of Cross-Cutting Relationships
Law of Superposition 
In undisturbed layers, the oldest layers are at the bottom and the youngest are at the top
Principle of Original Horizontality
Layers of sediment are originally deposited horizontally
Principle of Cross-Cutting Relationships 
Features that cut across layers (e.g., faults or intrusions) are younger than the layers they cut through
Uses of relative dating
Establishes a sequence of events rather than an exact age
These summaries highlight the key aspects of radiometric and relative dating methods