Exam 2 Lecture Outline Special Lecture Observed Examples of Evolution Stephanodiscus yellowstonensis Diatom From Stephanodiscus niagarea Evolution caused by rapid shifts from 14 000 to 10 000 years ago o Cold grasslands to warm forests o Drier climate Started with S niagarea and evolved into S yellowstonensis over 13 000 10 000 years ago o Lower number of spines Punctuated equilibrium Directional selection Rhagoletis pomella apple maggot Lays eggs on the Hawthorne tree larvae eat the fruit o Life cycle dependent on when the tree sets fruit 17th and 18th century apples brought to and distributed across north America 19th Rhagoletis pomonella reported infesting apples Not a separate species although the populations have changed their life cycles and often don t interbreed still 4 gene flow o In the process of speciation Mayr definition Lecture 1 Systematics Taxonomy Taxonomy science of classifying and naming organisms Systematics science of creating and evaluation classification schemes Carl Von Linne Linnaeus o Uppsala for medical training Surveyed Lapland anthropology on the Sami people drums for spirit world o MD from Hardewyk o Systema Naturae organized plants and animals in a hierarchical scheme Established systematics basic classification and naming still used today o Binominal Nomenclature Italicized underlined 2 Latinized Greek words Genus noun capitalized refers to a group of organisms Specific epithet adjective never capitalized characteristic might apply to other organisms Proper use Can abbreviate the genus Might include namer and date of discovery Defining a species o Linnaean definition morphotype species all organisms in a species have shared characteristics Doesn t account for Behavior biochemistry or differences among populations o Modern definitions of species accounts for genetics Mayr biological species genetically isolated set of populations that share a common gene pool in their natural environment and are isolated from other such groups Effective gene pool Limitations fossils asexual species allopatric species geographically isolated Must have sexual lifestyle o Other definitions of species Recognition species based on mate identification and selection behavioral Cohesion species expansion of recognition to include the post zygotic barriers Ecological based on the niche they occupy Phylogenetic species sequence of ancestral descendant populations species is the smallest group of individuals with a common ancestor Folk species how local cultures identify a species Larger Linnaean categories o Species genus family order class phylum kingdom domain Creating phylogenies o Monophyletic group ancestor and all descendants o Paraphyletic group ancestor and not all descendants o Polyphyletic group more than 1 ancestral line o Methods Moved from classical fighting over classification to phenetics ignored analogies to cladistics evolutionary developments o Cladistics identify pleismorphies ancestral characters and show evolution of apomorphies derived evolutionary novelties Molecular cladistics compares genetic data Make phylogenetic trees hypotheses Kingdoms o Linnaean 2 Plantae and Animalia o Margulis 5 Plantae Animalia fungi Monera Protista Monera and Protista were polyphyletic Monera included all prokaryotes o Now 3 domains with lots of kingdoms Bacteria Achaea more related to Eukaryotes None None Pseudopeptidoglycan n acetylosaminuronic acid Branched Monolayer Ether linkages Several types No Yes Yes Some Eukarya Present Present None Unbranched Bilayer Ester linkages Several types Neo No no Yes Nuclear envelope None None Membrane bound organelles Peptidoglycan in cell walls Membrane lipids Unbranched Present n acetyl muronic acid Bilayer Ester linkages RNA polymerase 1 type Yes Yes No No Antibiotic sensitive Circular DNA Extremophiles Histones associated with DNA Initiating amino acid Formyl methionine Methionine methionine Lecture 2 Prokaryotic Domains 4 5 billion years ago life arose 750 million years ago fossil record starts Miller Urey Experiment o Simulated the formation of organic molecules in a reducing atmosphere o Added o What they did o Got out Water Methane Hydrogen gas Ammonia Simulated the water cycle Had electrodes to simulate lightning Organic molecules Amino acids 13 22 predominantly glycine Change in atmosphere from reducing to oxidizing o Ferrous Fe2 to ferric Fe3 o Ferrous is soluble Ferric is insoluble iron ore deposits o Caused by photosynthetic organisms raising the atmospheric oxygen LUCA last universal common ancestor o Unclear because of all the horizontal gene transfer Prokaryotic cells o Shapes Bacillus rods Vibrio commas Coccus spheres Spirilli helical external flagella Spirochetes long helical with axial filaments o Cell wall prevents osmotic swelling in a hypotonic environment Mycoplasmas no cell walls live in isotonic environments Peptidoglycan amino sugar and short amino acids covalently cross linked into 1 large macromolecule Peptides n acetyl glucosamine n acetyl muronic acid Gram staining Gram positive o Thicker cell wall 20 nm 90 peptidoglycan o Penicillin sensitive o purple o Outside the cell membrane Flagellum made of protein flagellin Fit into socket in cell surface Cell movement Gram negative o Thinner cell wall 10 15 nm 20 peptidoglycan o High lipid content o Pink gram stain Pilus fimbria shorter rigid and nonmotile Sex pili used for bacterial conjugation Capsule goopy polysaccharide coat outside the cell wall Helps evade host defenses phagocytosis Most bacteria with capsules are pathogenic o Inside the cell membrane Cell membrane 7 nm thick No cholesterol Phospholipid bilayer Mesosome doesn t really exist folded looking part of membrane probably a remnant of microscopy Cytoplasm nothing fancy Photosynthetic cyanobacteria have photosynthetic lamellae Nucleoid genophore compact mass of DNA circular DNA attached to cell membrane at some point Plasmid rings of DNA 2 30 nucleotides long Ribosomes 24 nm sensitive to antibiotics Spores dormant stage Heavy cell wall and dehydrated cytoplasm Resistant to drying chemicals and heat Metabolically inactive o Reproduction of Prokaryotes Binary fission split in two Asexual Only to increase numbers no genetic variation is created clones Sexual exchange methods Conjugation F to F transfer of genetic material between bacteria through o Iron bacteria sex pili Transduction genes carried by bacteriophages Transformation taking up plasmids o Metabolism and nutrition Autotrophy doesn t need an
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