Quantifying evolution by natural selection

Area of Science:

• Evolutionary Biology
• Population Genetics
• Mathematical Biology

Background:

• Fisher's Fundamental Theorem of Natural Selection (FTNS) is a cornerstone in evolutionary theory.
• The FTNS quantifies the rate of increase in mean population fitness due to natural selection.
• However, the FTNS has recognized limitations in fully capturing selection dynamics in Mendelian populations.

Purpose of the Study:

• To identify and elaborate on the deficiencies of Fisher's FTNS.
• To present a new mathematical theorem for quantifying natural selection.
• To offer an alternative perspective on natural selection's impact on gene frequencies.

Main Methods:

• Comparative analysis of Fisher's FTNS and a newly developed theorem.
• Focus on the algebraic and conceptual differences between the two theorems.
• Examination of how each theorem models changes in gene frequencies versus mean population fitness.

Main Results:

• The paper details specific deficiencies within Fisher's FTNS.
• A new theorem is proposed that focuses on changes in gene frequencies.
• The new theorem offers a different approach and conclusions compared to the FTNS, despite some algebraic similarities.

Conclusions:

• Fisher's FTNS has inherent limitations for quantifying natural selection in Mendelian populations.
• The newly proposed theorem provides a more accurate and comprehensive framework for understanding selection.
• This work offers a novel perspective on the evolutionary implications of changes in gene frequencies.