CAREER: Empirical Tests of the Fundamental Theorems of Evolution and Natural Selection

This project will be the first to experimentally test the long-standing theory that change in average individual fitness within a population due to the effects of natural selection sets the rate by which traits of organisms evolve and populations adapt to their environments. Darwinian fitness, or individual survival and reproduction, is a foundational concept in biology. Scientists have hypothesized that the rate at which a population adapts is predicted by the genetic inheritance of individual fitness. Such a hypothesis could enable the forecasting of evolution and population dynamics, allowing scientists the ability to predict how natural populations respond to future environmental changes and if populations will persist or go extinct. The goals of this project are to establish a research program to (1) improve evolutionary predictions and (2) integrate education programs that train students and teachers to conduct hypothesis-driven research. The education component will teach high school teachers and students about evolution by natural selection while training them to conduct their own scientific research through independent projects that will further the project’s overall research goals. These plans involve students at the high school and undergraduate levels and seek to train high school teachers from throughout Alabama. Through involvement of several thousand students from across Alabama, this project’s activities address basic science literacy, engagement in STEM, and development of STEM educators and educational resources. Fisher’s fundamental theorem of natural selection expresses the rate of population mean fitness change due to natural selection as a function of the additive genetic variance for fitness. The fundamental theorem of evolution is a broader statement about fitness change that includes the response due to natural selection and additional forces acting on population mean fitness. Despite a long history of theoretical development, there has been little empirical testing of either the fundamental theorems of evolution or natural selection. This project is a first-of-its-kind study to experimentally manipulate additive genetic variance for fitness among replicate populations of seed beetles (Callosobruchus maculatus) to test the theory that this genetic variance is the key quantity predicting the rate of change in population mean fitness. The project will then connect estimates of genetic variance in fitness with genetic covariance quantifying environmental deterioration for fitness arising from conspecific interactions. The impacts of conspecific competition and sexual conflict on fitness evolution address a long-standing, but unresolved debate whether sexual selection provides net costs or benefits to populations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.