Natural, Relaxed, and Artificial Selection
- 1. Natural, Relaxed, and Artificial Selection Hasan Mahmud
- 2. Natural Selection Is the basis of the other types of selectionCompetition VariationHeriatble Difference in survivalRelaxed and Artificial Selection are simply natural selection under different Each of the two change different parameters and
- 3. Relaxed Selection Is a selective phenomena that occurs when selective pressures are either elimatedor dramatically reduced Are many new cases as society becomes more and more complex
- 4. Examples of Relaxed Selection When selective pressures are reduced or eliminated they can be biotic or abioticBiotic examples Predation elimination Elimination of pathogenAbiotic examplesChanges in light and temperature and waterChanges soil and mineral composition
- 5. Modern Medicine Modern MedicineElimination of Many diseases that used to be lethalCompensation for Chronic and Genetic DiseasesHelps with common health problemsSight problemsHearing problems
- 6. Other Examples Malaria resistanceWithout the pressure of possible infection there is no heterozygous advantageGalapagos Without the presence of predators and the abundance of food many animals in the Galapagos have become much larger than their main land counterparts
- 7. Problems with Relaxed Selection Many of the problems with relaxed selection only come into play when those pressures are re-introducedWhile some times the organism has come up with new way to deal with the pressures other times can be very costly to the pouplation
- 8. Artificial Selection Usually through intention human involvement the selection of non-essential traits in a populationMany times the means through which selection is done is harmful to the populationArtificial selection is done for two purposesTo increase production such as milk, eggs, meatEnhancement of desired traits e.x dogs horses
- 9. Misconception of Artificial Selection Artificial Selection does and cannot create new traitsUses recessive traits or enhances existing traits to unusual expression Many of the artificially created species can still breed with ancestral species
- 11. Problems with Artificial Selection While some examples of artificial selection are not intentional Initial domestication of AnimalsInitial enhancement of cropsMany examples of Artificial Selection are done through in breeding Purebred dogsRace horses
- 12. Connections Artificial, Relaxed, and Natural Selection are not separate and different forcesEach is just a subset of the larger evolutionary force Artificial selection is taken to the extreme where there is a desired goalRelaxed selection is the absence of pressure and the evolutionary pathways that forms
- 13. Works Cited http://images.google.com/imghp?gbv=2&um=1&hl=en&btnG=Search+Images1 Bryant, Edwin H. "Fitness Decline under Relaxed Selection in Captive Populations." Conservation Biology 13 (2001): 665-69. 2 "Evolution and Natural Selection." Evolution and Natural Selection. 10 Oct. 2008. Universtiy of Michigan. 5 Nov. 2008 <http://www.globalchange.umich.edu/globalchange1/current/lectures/selection/selection.html>. 3 Foster, Susan A., and John A. Endler. "Effects of Relaxed Selection Evolutionary Behavior." Geographic Variation in Behavior. 4 Gayle, Lisa. "Genetic Disorders." Encyclopedia of Childhood and Adolescence 42 (1998).5 Guyon, Isabelle. "An introduction to variable and feature selection." The Journal of Machine Learning Research 3 (2003): 1157-182. 6 Innan, Hideki. "Pattern of polymorphism after strong artificial selection in a domestication event." Biological Science 109 (2004): 106667-0672. 7 "Malaria and the Red Cell." 02 Apr. 2002. Information center for sickle and thalessis Disease. 28 Nov. 2008 <http://sickle.bwh.harvard.edu/index.html>.8 Robertson, A. "A Theory of Limits in Artifical Selection." Proceedings of the Royal Society of London. Series B, Biological Sciences 153 (2000): 234-49.