* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download 11.3 Other Mechanisms of Evolution TEKS 7D, 7F Genetic drift is a
Behavioural genetics wikipedia , lookup
Gene expression programming wikipedia , lookup
Adaptive evolution in the human genome wikipedia , lookup
Genetic testing wikipedia , lookup
Inbreeding avoidance wikipedia , lookup
History of genetic engineering wikipedia , lookup
Public health genomics wikipedia , lookup
Heritability of IQ wikipedia , lookup
Genetic engineering wikipedia , lookup
Genome (book) wikipedia , lookup
Group selection wikipedia , lookup
Designer baby wikipedia , lookup
Dual inheritance theory wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Human genetic variation wikipedia , lookup
Koinophilia wikipedia , lookup
Genetic drift wikipedia , lookup
11.3 Other Mechanisms of Evolution The student is expected to: 7D analyze and evaluate how the elements of natural selection, including inherited variation, the potential of a population to produce more offspring than can survive, and a finite supply of environmental resources, result in differential reproductive success and 7F analyze and evaluate the effects of other evolutionary mechanisms, including genetic drift, gene flow, mutation, and recombination TEKS 7D, 7F 11.3 Other Mechanisms of Evolution TEKS 7D, 7F KEY CONCEPT Natural selection is not the only mechanism through which populations evolve. 11.3 Other Mechanisms of Evolution Gene flow is the movement of alleles between populations. • Gene flow occurs when individuals join new populations and reproduce. • Gene flow keeps neighboring populations similar. • Low gene flow increases the chance that two populations will evolve into different species. bald eagle migration TEKS 7D, 7F 11.3 Other Mechanisms of Evolution TEKS 7D, 7F Genetic drift is a change in allele frequencies due to chance. • Genetic drift causes a loss of genetic diversity. • It is most common in small populations. • A population bottleneck can lead to genetic drift. – It occurs when an event drastically reduces population size. – The bottleneck effect is genetic drift that occurs after a bottleneck event. 11.3 Other Mechanisms of Evolution TEKS 7D, 7F • The founding of a small population can lead to genetic drift. – It occurs when a few individuals start a new population. – The founder effect is genetic drift that occurs after start of new population. 11.3 Other Mechanisms of Evolution TEKS 7D, 7F • Genetic drift has negative effects on a population. – less likely to have some individuals that can adapt – harmful alleles can become more common due to chance 11.3 Other Mechanisms of Evolution TEKS 7D, 7F Sexual selection occurs when certain traits increase mating success. • Sexual selection occurs due to higher cost of reproduction for females. – males produce many sperm continuously – females are more limited in potential offspring each cycle 11.3 Other Mechanisms of Evolution TEKS 7D, 7F • There are two types of sexual selection. – intrasexual selection: competition among males – intersexual selection: males display certain traits to females