BIOLOGY 152 Lecture Notes - Lecture 7: Small Population Size, Genetic Drift, Stabilizing Selection

17 views2 pages
18 Feb 2017
Department

Document Summary

Directional selection: only a certain trait survive and reproduce. A trait has to be heritable for a population to respond to selection to evolve. Evolution by natural selection can only change with genetic change because evolution is a change in allele frequency over generations. However, pure natural selection can happen without genetic change. Also known as migration- always bring alleles into or out of a population. Loss of alleles/influx of alleles causes evolution in gene flow. One allele will be fixed over time (until new alleles arise through mutation) Sampling error in drawing of gametes to make zygotes. Frequency of only one allele shown for a gene with the alleles in the population. Founders effect- small population size= strong effects of genetic drift. Genetic bottleneck makes a recovery when avoiding extinction in a small population. Alleles may be fixed in a population or may be lost as a consequence of this process.

Get access

Grade+
$40 USD/m
Billed monthly
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
10 Verified Answers
Class+
$30 USD/m
Billed monthly
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
7 Verified Answers

Related Documents

Related Questions