PPT-Genetic signatures of natural selection

Jamie Winternitz Institute of Botany and Vertebrate Biology Czech Academy of Sciences Outline of talk The Chimp and the River Negativefrequency dependent selection Phylogenetic methods The Island Fox. and Evolution. DNA and Heredity . As seen in the section on Taxonomy, modern classification of organisms is being shaped by our understanding of genetics; of DNA.. DNA is a polymer (many molecules attached to one another) of nucleic acids. A nucleic acid is monomer (one molecule) that contains three parts:. A) Directional selection. Chance events . Stabilizing selection . Disruptive selection. Answer Key – LO 1.2. Directional selection is most common wen a population’s environment changes or when members of a population migrate to a new habitat with different environmental conditions than their former one. Stabilizing selection acts against extreme phenotypes and favors intermediates variants. Disruptive selection occurs when environmental conditions favor individuals on both extremes of a phenotypic range over intermediate phenotypes. An example of directional selection is that black bears in Europe increase with size during the colder weather, only to decrease during the warmer weather. An example of stabilizing selection is the birth weights of most human babies lie in the range of 3-4 kg; babies who are much smaller or larger suffer higher rates of mortality. An example of disruptive selections is black- bellied seed cracker finches have two different beak sizes for cracking different types of seeds. . Natural Selection does not always proceed in the expected direction, because several forces could interfere with the action of Natural Selection. Constraints on Natural Selection. Genetic . Variation. EVOLUTION. What is Evolution?. . What is Evolution?. A process of biological change over generations that makes descendants become gradually . different. from their ancestors. Charles Darwin. gets much of the credit for the theory of evolution . The Smallest Unit of Evolution. A common misconception is that organisms evolve during their lifetimes. Natural selection acts on individuals, but only populations evolve. Consider, for example, a population of medium ground finches on Daphne Major Island. process. Written in the genetic code of species alive today. Story of life on earth is the story of the molecule of life---DNA---and the various ways in which it manifests itself, in the form of living species in order to survive. Edition. AP Biology. Chapter 23. The Evolution of Populations. Individuals do not evolve, . populations do over time. Individuals . do not evolve. , populations do. Medium Ground Finch from island of Daphne Major in Galápagos Islands. What is natural selection?. It’s the . process whereby organisms better adapted to their environment tend to survive and produce more offspring. . The . theory. of its action was first fully . explained . March 5, 2014. 1. Evolutionary Computation (EC). 2. Introduction to Evolutionary Computation. Evolution is this process of adaption with the aim of improving the survival capabilities through processes such as . Motivation. Most powerful mode of evolution. Explains observation of Descent with Modification. Nonrandom survivorship/reproduction of individuals based on particular features of their phenotype. . Any environmental agent may be the cause of natural selection. Golden Girls Plus Alex Media Room B Group. Presentation Date: 140523. Presenters: Alex Bentley. . 288531. Nancy . Bocanegra. 320379. Cathy Odom 128180. . Golden Girls Plus Alex Media Room B Group. Presentation Date: 140523. Presenters: Alex Bentley. . 288531. Nancy . Bocanegra. 320379. Cathy Odom 128180. . Recent Evolution in Humans. Evolution is very much still happening today — and it's happening to us.. Right here, right now.. Our genes constantly change over time thanks to the power of selection.. A) Directional selection. Chance events . Stabilizing selection . Disruptive selection. Answer Key – LO 1.2. Directional selection is most common wen a population’s environment changes or when members of a population migrate to a new habitat with different environmental conditions than their former one. Stabilizing selection acts against extreme phenotypes and favors intermediates variants. Disruptive selection occurs when environmental conditions favor individuals on both extremes of a phenotypic range over intermediate phenotypes. An example of directional selection is that black bears in Europe increase with size during the colder weather, only to decrease during the warmer weather. An example of stabilizing selection is the birth weights of most human babies lie in the range of 3-4 kg; babies who are much smaller or larger suffer higher rates of mortality. An example of disruptive selections is black- bellied seed cracker finches have two different beak sizes for cracking different types of seeds. .