Image Caption
The marble-drawing scenario also illustrates why drift affects small populations more. Imagine that your bag is only big enough for 20 marbles (a tiny bag!) and that you can only draw four marbles to represent gene frequencies in the next generation. Something like this might happen:
Image use policy: For non-commercial, educational purposes, this image may be used with a Creative Commons CC BY-NC-SA 4.0 license. Please credit as follows: © University of California Museum of Paleontology, Understanding Evolution, www.understandingevolution.org
See where this image appears on the Understanding Evolution website »