BIOL 112 1st EditionLecture 8Outline of Last Lecture I. Condition #2: No MutationsII. Condition #3: No Emigration or ImmigrationIII. Condition #4: Reproductive SuccessIV. Mathematical Models of Natural SelectionV. Different Types of SelectionVI. Allopatric SpeciationVII.Physical Isolation Leads to Genetic IsolationOutline of Current LectureVIII. Observed SpeciationIX. QuestionsX. Shift in Host AvailabilityXI. Divergence of Fly PopulationsXII.Speciation in Action?XIII. Classification and DiversityXIV.Naming OrganismsXV. Carl von LinnéXVI. Systema NaturaeXVII. Binominal System of NomenclatureXVIII. Genus NameXIX. Specific Epithet (Descriptor)XX.Proper Use of BinominalXXI. What is a Species?XXII. Ways of DefiningXXIII. Larger Linnaean CategoriesCurrent LectureI. Observed Speciation Has anyone seen a species emerge?Several cases documented of the generation of genetically isolated populations (species) in the laboratoryBut also a number of examples of what appears to be speciation in action in field populationsDocumented (Therio) example of speciation with intermediate types in fossil recordThese 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.•S. yellowstonensis descendent from S. niagarae•Centric diatom (alga) found only in Lake Yellowstone•Diatom species defined by details of silica cell wall structuresApparent directional selection is to produce new speciesExtremely rapid evolution of an organism: speciation in about 3,000 to 4,000 years, followed by no subsequent changeRapid speciation perhaps driven by rapid climactic shift at the end of the Ice AgeII. Questions Why speciation only in Lake Yellowstone, and not adjacent lakes?Did climactic shift drive rapid speciation? How? What selective pressures?Does this apply to other diatoms/protists?Another Example: Rhagoletis Pomonella•Railroad worm, or apple maggot -- Parasitic fly, native to N. America•Lays eggs on fruit of hawthorn tree•Maggots eat fruit, pupate over winter, and emerge as adult flies to mate and lay eggs on new fruitTiming of mating and egg laying depends on time tree sets fruitsIII. Shift in Host Availability Apples and other domestic fruit trees imported to N. America and planted during expansion European settlements in late 18th-early 19th CenturyApple (Malus domesticus) not a native North American species"Johnny Appleseed," John Chapman (1774 - 1845) went around selling Apple treesBy mid-19th Century, observers noticed that the these maggots (Rhagoletis) were infesting apples, which had not happened beforeIV. Divergence of Fly PopulationsTwo different population of flies ("races") now identified:•Those attacking the hawthorns•Those attacking the applesHawthorn population does not infest apples; apple population does not infest hawthornsTiming of mating, egg laying, and life span of larval stage are all coordinated to specific tree host species, and are very differentV. Speciation in action?Two populations are distinct in behavior, genetic content, and life cycleBlooming and fruiting times of apples and hawthorns are very differentFly populations have shifted their mating/egg laying timing to match host tree speciesPopulations differ at several genetic lociLittle hybridization: perhaps as little as 4-6% genetic exchange between two populations -- very little gene flowTwo populations could be in the process of becoming genetically isolated -- which is in the definition of speciationSystematics/Taxonomy (Chapters 25-26)VI. Classification and DiversityCategorize living things into groups -- but why do we need to do this?Uses for systematics:•Aids understanding of structures and functions of components and organs•Aids understanding of evolution and "family tree" of organisms: good systematics should reflect evolutionary history•Aids rapid identification of relatives of previously unknown organisms•Provides a framework to learn (and remember) different types of organismsTaxonomy -- science of naming organisms and groups of organisms, one part of the larger activity which is systematicsSystematics -- science of developing and evaluating classification schemesVII.Naming OrganismsFrog -- Leopard Frog (used in the North) -- Grass Frog (in other parts of the country)Use of common names gives problems:•Language differences•Different regional namesWe can solve this by giving this particular creature an unambiguous, scientifically significant name.Older Approach: Elaborate Descriptions•Long descriptions in Latin•Example: Honeybee -- Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatis.•Unwieldy system and too many words -- obviously•Needed innovation and reformVIII. Carl von Linné (1707 - 1778)•Carolus Linnaeus (latinized version of name)•Son of Swedish clergyman, grew up poor; was thought to be stupid (because he was more interested in natural sciences than in the standard curriculum - latin/greek); nearly apprenticed to be a shoemaker•1728 -- went to University of Uppsala (sweden) for medical training. Showed outstanding promise and was giving lectures on botany while still a sophomore•1732 -- sent by Academy of Sciences of Uppsala on collecting expedition to Lapland (unexplored territory by the arctic circle). In 6 months, he covered 1,200 miles on foot andby horse, collecting botanical, geological, and anthropological information about country and people (Lap-people/Sámi)•1735 -- received M.D. from University of Hardewyk (Holland)•1735 -- Major scientific contribution first published, Systema Naturae. (First edition was 12pgs. so more like a pamphlet) The 10th Edition (1758) is regarded as definitive (nearly 1,400 pgs.)•1741 -- appointed Professor of Botany at University of Uppsala; scientific work won him world-wide reputation•1761 -- granted title of nobility by Swedish crown (allowed the addition of the "von" to his name)IX. Systema NaturaeOrganized all plants, animals, and rocks into hierarchical scheme of nested categoriesTenth Edition (1758) is regarded as most developed ("definitive") versionEstablished major innovations to the science of systematics, basic set of rules for organization and naming still used todayHis books were originally kept away from students because it was regarded as pornographic because of focus upon sexual life cycles as important identification characters.Linnaean InnovationsLinnaean