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Pantherophis Guttatus • Common Names: Corn Snake, Red Rat Snake

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Organismal Biology Organism-of-the-week: Pantherophis guttatus Common names: corn snake, red rat snake, chicken snake, etc. Arboreal=tree dwelling Species= Pantherophis guttatus o Common name: corn snake o Rules for species: . Binomen= two name . First name= Genus Always capitalized Always underlined OR italicized Plural: Genera . Second name= Specific Epithet Not capitalized Always underlined OR italicized Genus= Pantherophis o Common name: rate snake o Plural: Genera Family= Colubridae o Non-venomous snakes o Family usually ends in –idae or –aceae Order= Squamata o All snakes and lizards o Suborder= serpentes . Just snakes . Suborders usually start with: Sub-, super-, Infra- Class=Reptilia o Common name: reptiles Phlyum= Chordata o Common name: vertebrates and other chordates o Plural: Phyla Kingdom= Animalia o Common name: animals Biology= Study of life Bi= two o Plants and animals -ology= the study of Biodiversity= study of how organisms are different Survey Cladistics= common ancestry is the primary criterion used to classify organisms Clades= groups that contain an ancestral species and all of its descendents o Equal to a monophyletic group Monophyletic= single ancestor o Holophyletic= all descendents of the single ancestor o Paraphyletic= some but not all of descendents of the single ancestor o Monophylogeny is what we strive for Polyphyletic= more than one ancestor o (Not good) Plesiomorphic= around for a long time o Ancestral Apomorphic= newly evolved characteristic o Derived Symplesiomorphic= shared ancestral characteristic Synapomorphic= shared derived characteristics o This is what scientists want to avoid polyphyletic groups Autapomorphic= single unshared characteristic Systematics Taxonomy= the naming and classification of organisms o Taxon: the named taxonomic unit at any level of the hierarchy Example= snake Plural: taxa o Taxonomic revisions—why? (1) New information Molecular vs morphological Similarities among organisms o Analogous= common environment . having characteristics that are similar because of convergent evolution . Not ancestral traits . Not used for classification o Homologous= come from same ancestors . Similar in characteristics resulting from a shared ancestry . Used for classification . Ancestral traits . What scientists want! (2)Different philosophy Dendogram (phylogram): family tree (3)Change: just because someone feels like changing it Phlogeny= evolutional history (natural selection) Classification= way of categorizing organisms Survey: 3 Domains, 6 Kingdoms, 35-40 Phyla Domains: Eukarya- True nucleus Archae- no nucleus or other membrane organelles Bacteria- no nucleus or other membrane organelles Eukarya: Kingdoms o Animalia . Movement . Cell membrane o Plantae . Cell wall . Autotrophic o Fungi . Cell wall . Almost no movement . Heterotrophs o Protista . Difficult to explain . Variety Prokaryotes= Bacteria and Archae Not an official taxon The grouping of bacteria and archae as prokaryotes is incorrect because archaea is more related to eukarya than it is to bacteria Diversity o 2 domains o 2+ kingdoms Size o Small o Most are 1-5 m (micrometer) Shape o ⃝ –coccus . Plural: cocci . Spherical in shape o Oval shaped –bacillus . Plural: bacilli o ~~-- Spirilla . Plural: spirillae o Solitary vs colonial . Solitary= found alone . Colonial= found in groups Strepto- o OOOOOOO o One line Staphylo- o Clusters Cell Wall o Present in most o Has a different chemistry than the one animals have o Variable . Example: Gram Stain A staining method that distinguishes between two different kinds of bacterial cell wall Used to look at cell wall Positive/negative o Gram negative= describing the group of bacteria that have a cell wall that is structurally MORE complex and contains LESS peptidoglycan than the cell wall of a gram-positive bacteria. Gram negative bacteria are often more toxic than gram positive bacteria. o Gram positive= describing the group of bacteria that have a cell wall that is structurally LESS complex and contains MORE peptidoglycan than the cell wall of a gram-negative bacteria. Less toxic than gram-negative o Peptidoglycan is a type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides o Capsule . Fimbria Plural: fimbriae A short, hairlike appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells o a substrate is the surface on which a plant or animal live Thinner and shorter than flagellum . Pilus Plural: pili In bacteria, a structure that links one cell to another at the start of conjugation, also called a sex pilus or conjugation pilus o Conjugation is the direct transfer of DNA from one bacterial cell to another bacterial cell AKA “sex” pilus Motility o Flagellum . A long cellular appendage specialized for locomotion . There are different types . Plural: flagella o Taxis= an oriented movement toward or away from a stimulus . Phototaxis- move toward or away from light . Chemotaxis- move toward or away from a chemical Genome o Nucleoid= a non-membrane enclosed region in a prokaryotic cell where its chromosome is located o Ring shaped DNA o Plasmids= a small circular double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome. Reproduction o Asexual reproduction . No meiosis . The generation of offspring from a single parent that occurs without the fusion of gametes. In most cases, the offspring are genetically identical to the parent o Binary fission . Splits two ways . A method of asexual reproduction by “division in half”. In prokaryotes binary fission does not involve mitosis (but it does in eukaryotes) . Usually pretty rapid, but time varies o Budding o Endospores= a thick-coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditions . Very resistant . Dormancy and dispersal Nutritional Mode o Heterotrophic= heterotrophs are organisms that obtain organic food molecules by eating other organisms or substances derived from them . Decomposers= an organism that absorbs nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms and converts them to inorganic forms; aka a detritivore . Pathogenic- causes disease o Autotrophic= autotrophs are organisms that obtain organic food molecules without eating other organisms or substances derived from other organisms. They use energy from the sun or from oxidation of inorganic substances to make organic molecules from inorganic ones. Photoautotrophic= capable of synthesizing their own food from inorganic substances (carbon dioxide) using light as an energy source . Chemoautotrophic= an organism, typically a bacterium, that derives energy from the oxidation of inorganic compounds o Photoheterotrophs= organisms that use light for energy (ATP), but cannot use carbon dioxide as their sole carbon source. They must obtain carbon in organic form. Oxygen Relationships o Aerobic= with oxygen o Anaerobic= without oxygen o Facultative= can use oxygen, but can survive without it o Strict= obligate= cannot survive with oxygen OR cannot survive without oxygen Ecological Relationships o Free-living= do not depend on another organism for survival o Pathogen= depends on another organism for survival . An organism or virus that causes disease o Symbiont= provides a benefit for the organism . The smaller participant in the symbiotic relationship, living in or on the host o Free-living heterotrophs= decomposers o Biofilms= surface coating colony of one or more species of prokaryotes that engage in metabolic cooperation . Lives on surfaces of water, etc. Community . Combination of species . Waste products used by the community Organism-of-the-week: Species: Nostoc commune o Common name: star jelly, mare’s eggs, witch’s butter, monster boogers Genus: Nostoc Family: Nostocaceae Order: Nostocales Class: Cyanophyceae Phylum: Cyanobacteria Kingdom: Eubacteria Domain: Bacteria Characteristics: o Cosmopolitan= worldwide o N-fixation= the conversion of atmospheric nitrogen (N2) to ammonia (NH3) . N2NH3 o Desiccation resistant . Dormancy o Photosynthesis o colonial Domain Archae 1-4+ Kingdoms Kingdom Archaebacteria o Gram negative . Lack peptidoglycans Extremophiles o Love extreme conditions o Thermophiles= love extreme temperatures o Halophiles= love salty conditions Methanogens o Produces methane (CH4) as a waste productfossil fuel o Anaerobic Non-extreme archaea Domain Bacteria 1-200+ kingdoms Kingdom Eubacteria o Contains most of the familiar bacteria o Phylum Cyanobacteria . Performs photosynthesis . Internal membrane Looks like chloroplasts . Serial endosymbiotic hypothesis of Eukaryotic organelle origin A hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from small prokaryotes that had been engulfed by larger cells. Endosymbiosis= a relationship between two species in which one organism lives inside the cell or cells of another organism o Proteobacteria . Gram negative largest group . Escherischia Coli E. Coli Coliformin colon Gut flora Pathogenic strains o Alphaproteobacteria . Purple-green . Inner membrane looks like mitochondria (ring-shaped DNA) o Spirochaetes . Spirilla shape many pathogens o Gram Positive Groups: . Chlamydias all are animal diseases . Mycoplasmas Smallest of all bacteria No cell wall Ex: walking pneumonia Domain Eukarya
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