The fossil record provides a historical timeline of life on Earth, showcasing a variety of organisms that existed at different periods. This collection of fossils offers critical evidence that supports the theory of evolution in several ways.
Firstly, fossils demonstrate change over time. When we analyze layers of sedimentary rock, we find that older layers contain simpler life forms, while newer layers show more complex organisms. For example, fossils of early fish appear in older rock layers, while mammal fossils are found in much more recent layers, indicating a gradual evolution of species.
Secondly, the existence of transitional fossils, which showcase characteristics of both ancestral and descendant species (like the famous Archaeopteryx, which shows features of both dinosaurs and birds), provides clear evidence of the evolutionary process. These fossils fill in the gaps and show how species have split and evolved over millions of years.
Additionally, the geographical distribution of fossils supports the idea of common descent. Similar fossils found in widely separated locations (like the fossils of marsupials in both Australia and South America) suggest that these species share a common ancestor and have diverged over time due to geographic isolation.
In summary, the fossil record is like a book documenting the history of life, revealing a narrative of change, adaptation, and diversification that aligns with the principles of evolution. This substantial body of evidence across various disciplines confirms that life on Earth has evolved and continues to do so through natural processes.