Each species must be a selective force on the other

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Unformatted text preview: March 6, 2012 heterogeneity or sibling competition 2) Interactions with pathogens – progeny unlike parents – Red Queen Hypothesis 2. List the three conditions necessary for co ­evolution to occur (3 points): There must be genetic variation for characters in both species that influence their interaction.    Each species must be a selective force on the other species (i.e., affect the other's fitness).    There must a response to this selection in each species.  3. In a human population in which pyrimethamine is used to treat patients infected with Plasmodium falciparum (causing malaria), you find that the drug is no longer working. You sample Plasmodium and sequence the genomes of this parasite from a number of people. Your genome scan turns up the following result: Describe the pattern you observe, name and define the phenomenon and the mostly evolutionary scenario leading to this pattern (6 points): Reduced heterozygosity at the dhfr locus, due to a selective sweep from the drug, due to evolution of resistance in the Plasmodium. A selective sweep is a local reduction of variation after a new genetic variant is fixed by directional selection. As a new or preexisting mutation increases in frequency due to selection, regions of the genome linked to it are also driven to fixation. This leads to a reduction in variation around the selected variant. Also called hitchhiking. 3 ECOL 335 Evolutionary Biology NAME_____KEY________________ Sect#_____ Exam 2 Spring 2013 March 6, 2012 4. What are the requirements for evolution by natural selection to occur (6 points)? Dif...
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This note was uploaded on 02/02/2014 for the course ECOL 335 taught by Professor Reinthal during the Spring '10 term at University of Arizona- Tucson.

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