Skip to main content Accessibility help
×
Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-26T09:16:32.904Z Has data issue: false hasContentIssue false

8 - Phenotypic Change Documented in Field Studies

Published online by Cambridge University Press:  29 April 2019

Philip D. Gingerich
Affiliation:
University of Michigan, Ann Arbor
Get access

Summary

Analysis of 57 field studies yields a total of 814 independent step rates quantifying change from one generation to the next. The median step rate for field studies is h0 = 0.15 standard deviations per generation on a time scale of one generation. Step rates following directional selection in a laboratory setting have the same range of values as step rates observed in field studies. This consistency shows: (a) experimental selection is not artificial, but represents what we see in field studies; and (b) the change we see in field studies is what we expect for experimental and hence natural selection. Rapid change in a field study is change lying above a line fit to an empirical LRI distribution of step rates and base rates: change lying above Y = −0.784 ∙ X − 0.787, where Y is log10 of the rate r and X is log10 of the corresponding interval i. Empirically, the proportion of zero rates in field studies is 1.34%, mostly due to rounding, and zero rates have negligible effect on the rate statistics presented here. The anthropologist’s ‘secular trend’ of increasing human stature has rates in the range found here for evolution by natural selection.
Type
Chapter
Information
Rates of Evolution
A Quantitative Synthesis
, pp. 157 - 215
Publisher: Cambridge University Press
Print publication year: 2019

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×