Chapter 26 and 27 Notes
Chapter 26 and 27 Notes BIOL 2601 - 01
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BIOL 2601 - 01
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This 5 page Class Notes was uploaded by Suzanne Notetaker on Monday November 23, 2015. The Class Notes belongs to BIOL 2601 - 01 at Youngstown State University taught by Dr. Asch in Fall 2015. Since its upload, it has received 21 views. For similar materials see General Biology in Biology at Youngstown State University.
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Date Created: 11/23/15
Chapter 26 Taxonomy and Systematics Taxonomy Taxonomy science of describing naming and classifying living and extinct organisms and viruses Hierarchical system involving successive levels Each group at any level9 Taxon Highest level is DOMAIN Domains Bacteria Archaea and Eukarya Systematics study of biological diversity and evolutionary relationships among organisms Taxonomic groups are derived from systematics Binomial Nomenclature genus name and species label Genus name first letter of first word CAPITALIZED Both genus and species name Italicized or underlined thlogenetic Trees Phylogeny evolutionary history of species Propose phylogeny use systematics Trees usually based on morphological or genetic data Diagram that describes phylogeny Hypothesis of evolutionary relationships New Species can be formed by 1 Anagenesis single species evolves into different species 2 Cladogenesis species diverges into two or more species Monophyletic group or clade group of speciestaxon consisting of most recent common ancestor and all ancestors Smaller and more recent clades nested Within larger clades older common ancestors Paraphyletic group contains common ancestor and some NOT ALL its descendants Over time taxonomic groups Will reorganize so monophyletic groups are recognized Homology similarities among various species because derived from common ancestor Also can be homologous if derived from same ancestral gene Morphological Analysis Convergent evolution traits arising independently due to adaptation to similar environments Can cause problems Molecular Systematics analysis of genetic data to identify and study genetic homologies and propose phylogenetic trees DNA and amino acid sequences from closely related species are more similar than more distantly related species Cladistics study and classification of species based on evolutionary relationships considers various possible pathway changes then choosing tree with least complex explanation make phylogenetic trees or cladograms compares homologous traits characters that may exist in two or more character states Shared primitive character or symplesiomorphy 9shared by two or more different taxa and inherited from ancestors older than last common ancestor Shared derived character or synapomorphy 9shared by two or more speciestaxa and originated in most recent common ancestor 9basis of cladistics approach analyze shared derived characters to deduce pathway that gave rise to those species Branch point two species differ in shared derived characters Ingroup group interested in Outgroup species assumed diverged before species in the ingroup lack one or more shared derived characters found in ingroup Molecular Clocks favorable mutations are rare detrimental mutations quickly eliminated so Most mutations neutral constant rate used to measure evolutionary time not perfectly linear over long periods of time not all organisms evolve at same differences in generation times Chapter 27 Archaea and Bacteria Prominent features diversity Both domains and prokaryotic lack nucleus Domain Archaea features in common With eukaryotic nucleus and cytoplasm suggesting common ancestry Histone proteins ribosomal proteins and RNA polymerases Unique membrane lipids give resilience to heat and extreme environments extremophiles Also found in moderate conditions Extremophiles conditions 0 High salt content 0 High Acidity 0 High methane levels 0 High temperatures 0 Ex Methanopryus and Sulfolobus Domain Bacteria 50 bacteria phyla most favor moderate conditions some extreme Cyanobacteria photosynthetic bacteria abundant in fresh water oceans and wetlands and surfaces of arid soils bluegreen cyan color generate oxygen give rise to plastids display greatest structural diversity single colonies filaments produce organic carbon and fixing nitrogen Horizontal Gene Transfer movement of one or more genes from one species to another increase genetic diversity common among archaea amp bacteria large genetic changes Important Concepts both evolve from common ancestor eukaryotic nucleus and cytoplasm likely arose in ancient archaeal organism mitochondria and plastids from proteobacteria and cyanobacteria by endosymbiosis Structure and Movement small size 15 pm rapid growth simple cell structure Cellular Structure Thylakoids ingrowths of plasma membrane that increase surface area gas vesicles to adjust buoyancy nucleuslike bodies Cell Shape and Arrangement 1 Spheres cocci 2 Rods bacilli 3 Commonshaped vibrios 4 Spiralshaped spirochaetes exible sprilli rigid occur as single cells pairs or filaments Mucilage glycocalyx9 composed of polysaccharides protein or both 9 secreted from cells 9functions evade host defenses hold colony together biofilms Cellwall Structure most rigid outside plasma membrane maintain shape and help protect against attack avoid lysis archaea and some bacteria use protein most bacteria use peptidoglycan Gram Stain 1 Gram positive a Thick peptidoglycan layer b BluePurple dye held in layer c Cells stained bluepurple d Vulnerable to penicillin 2 Gram negative a Less peptidoglycan and thin outer lipopolysaccharide envelope b Pink stain c Cells stained pink d Resists penicillin and requires other antibiotics Motility allows cells to move to favorable conditions respond to chemical signals swim twitch glide or adjust otation Flagella protein in the filament helps with movement Pili threadlike structures on cell surface that twitchglide across surfaces important role in bacterial reproduction and disease processes Reproduction by binary fission divide by splitting in two Basis for widely used method of detecting and counting bacteria Can also use uorescent dye binds bacterial DNA to count bacteria Harsh Conditions 1 Akinetes a Found in aquatic filamentous cyanobacteria b Develop when winter comes c Survive winter and produce new filaments in spring 2 Endospores a Touch protein coat b Long dormant span c Found in some Grampositive bacteria Nutrition and Metabolism more diverse types of metabolism classified by nutrition oxygen response and presence of metabolic processes Nutrition Classification 1 Autotrophs produce all or most of own organic compounds 2 Photoautotrophs uses light energy for synthesis of organic compounds 3 Chemoautotrophs use energy from chemical modification of inorganic compounds 4 Heterotrophs require at least one organic compounds often more 5 Photoheterotroph use light energy to make ATP but must take in organic compounds from enVironment 6 Chemoorganotroph obtain organic molecules for energy and carbon source Oxygen Response Classification 1 Obligate aerobes require oxygen 2 Facultative aerobes can use oxygen or not 3 Obligate anaerboes can t tolerate oxygen 4 Aerotolerant anaerobes don t use oxygen but not poisoned by it Ecological Roles Biotechnology Applications 1 Carbon cycle a Producers synthesize organic compounds use by others as food b Decomposers break down dead organisms to release minerals c Methanogens make methane d Methanotrophs consume methane 2 Symbiotic roles a Symbiosis organism lives in close association With one another b Parasitism one partner bene ts from other s expense c Mutualism association benefits both partners d Pathogens parasitic microbe cause disease systems by obtaining organic compounds from liVing hosts parasites i Examples cholera tetanus pneumonia lyme disease typhoid tooth decay etc