Final answer:
The increase of recognizable species from deeper to upper rock layers in the fossil record indicates a long history of biological evolution, supported by Charles Lyell's principle of uniformitarianism.
Step-by-step explanation:
The observation that the number of recognizable species in certain groups increases from deeper layers to upper layers of rock has significant implications for our understanding of geological and biological history. This observation from the fossil record suggests that life on Earth has evolved over time, becoming more diverse and complex. In the mid-19th Century, geologists like Charles Lyell interpreted this to mean that Earth was much older than previously thought and that geological and evolutionary changes occurred gradually over vast stretches of time.
Lyell's interpretation fits with his theory of uniformitarianism, which proposed that the same geological processes we observe today have been occurring in a consistent way throughout Earth's history. This principle, which influenced thinkers like Charles Darwin, implied a much longer timescale for the Earth, allowing for slow but progressive evolution of species as evidenced by the fossil record. Specifically, Lyell would argue that the increase in species diversity seen in newer strata was evidence of this slow evolutionary change over a long period, rather than the result of sudden, catastrophic events.