UC Berkeley
Image Caption
This population of fish exhibits variation in body size. Some have genes for large size and some have genes for small size. This represents genetic variation in the population.
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 »
To save: 1) Click on image for the full-size version, 2) right-click (Windows) or control-click (Mac) on the image, and 3) select "Save image."
This image is part of a series:
Artificial selection (2 of 5) Fish example
When the population is fished, many of the largest fish are removed, so more of the small-bodied fish (and their small-bodied genes) remain.
Artificial selection (3 of 5) Fish example
The population reproduces. Each individual passes their genes on to their offspring; however, since there are more small-bodied parents, there are also more small-bodied offspring.
Artificial selection (4 of 5) Fish example
In the next generation, the population has evolved: average body size in the population is smaller than it used to be and small-bodied genes are more common than they used…