BIOL 152 1st Edition Lecture 7 Outline of Last Lecture I. Reconstructing Evolutionary Historya. Darwin proposes “Descent with Modification”i. Insight from others1. Hutton’s Gradualism2. Lyell’s uniformitarianism3. Lamark’s perspectives on fossilsb. Building phylogenetic treesi. Evolutionary Patternsii. Tracing genealogiesc. Analogous vs. Homologous characteristicsd. Hennig and phylogenetic characteristics i. Apomorphies ii. Plesomorphies iii. Synapmorphiesiv. Symplesiomorphiese. Phylogenies and classificationsi. Monophyletic groupsii. Paraphyletic groupsThese 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.iii. Polyphyletic groupsII. Cycling Carbon a. Charles KeelingOutline of Current Lecture I. Cycling Carbona. Charles Keelingi. Annual fluctuations in atmospheric carbonii. Steady increase in CO2b. Atmospheric CO2i. Influenced by1. Geology2. Biology3. Humansii. Varies across eonsiii. Evidence for contributions from fossil fuelsc. Carbon and biodiversityII. Diversity of Life-Prokaryotesa. Prokaryotes vs. Eukaryotesb. Bacteria vs. Archaeai. Differ in histones, metabolism, cell wall componentsc. Bacterial structurei. Cell wall1. Peptidoglycanii. Cell Shape1. Coccus, Bacillus, SpirillaCurrent LectureCycling CarbonCharles Keeling-- Tracked CO2- Saw annual fluctuationsHis work:1. Annual CO2 cycle2. Steady CO2 increaseAtmospheric CO2 increased by:- Geological processeso Volcanoeso Mid-ocean ridges- Biological Processeso Respiration- Humanso Deforestationo Burning fossil fuels Atmospheric CO2 decreased by:- Geological processes o Chemical weathering of rocks- Biological processes o Photosynthesis Keeling was the first person to understand the effects of CO2 in the atmosphereCO2 is produced during respirationPhotosynthesis and respiration use each other’s products as reactantsPlants use O2 during photosynthesis, not CO2Short term Carbon cycle - Carbon cycle by means of the complementary process of photosynthesis and respiration6 CO2 + 6 H2O >> C6H12O6 + 6 O2Carbon based organic molecules are called “energy molecules” because:- Energy is released when bonds in carbon-containing compounds are broken- Energy is stored in carbon-containing organic compounds - Energy is required to build carbon-containing compounds*CO2 increase correlates with Industrial Revolution*CO2 levels correlate with the temperature*Carbon isotope evidence correlates1. Geologically- produced CO2 has high 13C content2. Photosynthesis preferentially incorporates 12C3. Fossil fuels (coal, oil) are photosynthetic products4. Fossil fuels contain reduced 14C isotope content*Reduced 14C in atmospheric CO2 matches increased burning of fossil fuelsDoes correlation=causation?Carbon reservoirs (the importance of biodiversity)Microbial communities: The Earth before eukaryotesDiversity of life on Earth: Prokaryotes*Organisms with the longest history are still diverse and abundantEukaryotes- Membrane- Undergo mitosis- Linear DNA- Sex (genetic diversity)- Similar genes to ArchaeaArchaea- Live in harsh environment- Undergo mitosis- Special compounds within cell wall- Lack of membrane bound vacuolesBacteria- No membrane bound organelles- Cell walls contain peptidoglycan- Binary fission- Circular DNA- Limited size due to diffusionBacterial structure and diversity*Cell wall components- Gram staino Gram positive- thick peptidoglycan o Gram negative- thin peptidoglycan- Gram negative species are often toxic o Lipopolysaccharide layerShape of cells:- Coccus- Bacillus- Spirilla -
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