Experimental Evolution
Laboratory evolution experiments allow researchers to observe populations over many generations and identify genetic changes associated with adaptation and new traits.
The Investigative Question
What has experimental evolution actually shown evolutionary processes to accomplish?
What We Observe
Microorganisms can reproduce rapidly enough for researchers to observe thousands or tens of thousands of generations. Populations can be frozen, revived, compared with their ancestors, and genetically analyzed.
Scientific Background
Experimental evolution combines controlled environments with genomic and phenotypic measurements. Researchers can identify mutations, measure fitness effects, replay portions of evolutionary history, and test proposed mechanisms.
Why It Matters
These experiments provide unusually direct evidence about evolutionary processes because researchers can observe change as it occurs rather than relying entirely upon historical reconstruction.
What Is Known
Experimental populations have evolved changes in fitness, metabolism, resistance, regulation, morphology, and ecological interactions. Researchers can often identify genetic changes associated with these adaptations.
What Is Proposed
Results from laboratory populations are used to investigate general evolutionary principles and mechanisms that may also operate in natural populations.
What Remains Uncertain
Laboratory experiments occur under particular conditions and over limited periods. How directly particular experimental results correspond to major innovations in deep biological history must be evaluated case by case.
Design Relevance
Experimental evolution provides an important test for claims about what unguided evolutionary mechanisms can accomplish. It should therefore be examined carefully rather than either dismissed or extrapolated without limit.
Assessment
Experimental evolution gives us direct evidence of evolutionary change and should form an important part of any investigation into the creative capacity of evolutionary mechanisms.