BIOL 1108 Edition 1nd Lecture 4 Outline of Last Lecture I In the News II Gene Duplication and Divergence A Genetics B Hemoglobin C Types Subfunctionalization Pseudogenes and Neofunctionalization III Do monotremes and marsupials have the genes for fetal hemoglobin IV Extinction A Causes B Mass Extinction V Evolution A Macro vs Micro B Species C Types of Speciation Outline of Current Lecture I Learning objectives II Speciation A Allopatric B Sympatric III Bacterial Species A Classify These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute B Genetics C Definition IV Richard Lenki s Experiment Current Lecture I II III Learning objectives What is the textbook definition of a biological species and how might this species definition differ for a microbiologist What are the qualities of prokaryotes that make them difficult impossible to fit within the classic biological species concept Give examples of allopatric and sympatric speciation and describe the differences Be able to interpret a speciation event and to characterize it in terms of allopatry and sympatry What is the significance of Rich Lenski s work How does gradualism differ from punctuated equilibrium Speciation A Allopatric A physical geographic barrier that prevents interbreeding and leads to genetic isolation To create different species genetic diversity environmental changes and time to evolve B Sympatric Genetic isolation occurs within a population despite the lack of a physical barrier Ex Cichlid fish in Lake Victoria Specialize in niche food reproduction ect Overtime Bacterial Species Bacteria do not undergo meiotic sex A Classify 1 Appearance 2 Physiology 3 Habitat 4 Genetics B Genetics Bacterial species are defined by how tightly their hybridized DNA holds together If DNA of both species are similar then the amount of heat to break down the hybridized DNA is less C Definition a prokaryotic species is considered to be a group of strains that are characterized by a certain degree of phenotypic consistency showing 70 of IV DNA DNA binding and over 97 of 16S ribosomal RNA rRNA genesequence identity Richard Lenki s Experiment The E coli long term evolution experiment was begun in 1988 A dozen identical populations of asexual bacteria were grown collected and evaluated for accumulated differences Cultures in a minimal growth medium low glucose but with an excess of citrate Since E coli cannot transport citrate across its membrane it cannot use this carbohydrate as an energy source Cultures were placed in cryogenic preservation from which they could be thawed and regrown decades later Isolated a naturally occurring population that was able to metabolize citrate Cit Results from previous mutations that pre disposed the Cit strain to evolve This is referred to as Historical Contingency New species
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