Week two of Biology Notes
Week two of Biology Notes 103
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This 9 page Class Notes was uploaded by firstname.lastname@example.org Notetaker on Sunday January 31, 2016. The Class Notes belongs to 103 at Colorado State University taught by Tanya Dewey in Winter 2016. Since its upload, it has received 45 views. For similar materials see Life 103- Biology of Organisms in Biology at Colorado State University.
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Date Created: 01/31/16
Week two of Biology Notes 1/25 There are several biotic factors Organisms can have a positive, neutral, or negative affect on other organisms Examples: Plant and pollinator = positive reaction Predator and prey = positive for predator, negative for the prey Competition is a double negative reaction because they are competing for the same resource Commensalism- one benefits without causing any benefit or negative impact Mutualism- both benefit Abiotic factors Chemical Examples Ph and salinity of environment Physical Physical Weather temperature and moisture Nutrients Oxygen and Carbon Sunlight Dispersal- movement of individuals -can be one way trip Can be a round trip (migration) Prokaryotes are made up of 2 domains: Bacteria and Archaea Biologically, Prokaryotes are a non-monophylic group -they are mostly single-celled -highly adaptable -large numbers -high genetic diversity Bacteria -Unicellular -Smaller than Eukaryotic cells -Have a variety of shapes -spherical, rod-shaped and spiral are the 3 most common shapes Bacteria have cell walls -Help maintain shape -Protection -Prevents bursting in hypotonic environment -Contain peptidoglycan (which is sugar polymers linked by polypeptides Gram positive bacteria- cell wall on outside Gram negative bacteria- outer and inner membrane sandwich the cell wall -Have less peptidoglycan -More antibiotic resistance Some prokaryotes have a fimbria that allows them to stick to a substrate or other individual in a colony Most motile bacteria propel themselves by flagella -They are structurally and functionally different from eukaryotic flagella -Have ability to move in response to stimuli Both Bacteria and Archaea lack complex compartmentalism -Have no organelles -Some have specialized membranes Aerobic bacteria have respiratory membranes and thylakoid membranes Bacteria DNA -Genome is smaller than eukaryotes -Most genome consists of a circular chromosome -Some have plasmids Bacteria can form exospores or endospores Endospore -Internal -Resistant to UV radiation, alcohol and more -Survive for a long time Exospore -Formed differently -Less robust, can’t survive harsh environments -Disperse Genome Bacteria reproduction -Use binary fission and divide every 1-3 hours - Offspring is genetically identical -Mutation can cause variation in offspring How do Bacteria and Archaea increase diversity? -Rapid reproduction leads to more opportunities for mutations -Genetic recombination Genetic Recombination -Transduction, Transformation, and Conjugation Transformation -competent bacteria that can transform other genes - 1% are naturally competent and techniques can make bacteria artificially competent Transduction -Movement of genes by bacteriophages Conjugation -Genetic material is transferred between bacterial cells -sex pili allows 2 cells to connect together. F factor is required for the production of sex pili, but only one cell needs to be F+ 1/27 R plasmids carry antibiotic resistance -antibiotic resistant strains are becoming more common Why are they becoming more common? -Misuse and overuse of antibiotics -Agricultural uses -Patients wanting antibiotics for nonbacterial infections -Antibiotic products such as antibiotic soap -Lateral gene transfer allows cells to have resistance to multiple antibiotics MRSA -appeared in 1961, two years after Methicillin was first used -Now resistant to penicillin, oxacillin and more -85% infections occur in hospitals -Over 18,000 deaths in 2005 -Most are skin infections that then spread to organs Bacterial Nutritional Adaptations Phototrophs- get energy from light Chemotrophs- get energy from chemicals Autotrophys- require carbon dioxide Heterotrophys- Require organic nutrients to make organic compounds Oligate aerobes- need oxygen for cellular respiration Oligate anaeroves- oxygen is a poison. They use fermentation and anaerobic respiration -Falculative anaerobes can survive with or without oxygen Bacteria can metabolize nitrogen in a variety of ways -Nitrogen fixation- convert nitrogen to ammonia Metabilic Cooperation -allows bacteria to use environmental resources they could not use as individual cells -heterocytes- exchange metabolic products Proteobacteria -Gram negative - Phototrophs, chemoautotrophs, and heterotrophs -aneorabic or aerobic Alpha -related to eukaryotic hosts -mitochondria evolved from aerobic alpha via endosymbiosis -forms root nodules and fixes N Gamma -Sulfur bacteria -Resides in intestines and is not normally pathogenic -E. coli, salmonella, cholera Epsilon -Manty pathogens -cause blood poisoning Ecological Relationships -Symbiosis- 2 species live in close contact. The host is larger and the symbiont is smaller -Pathogens – parasites that cause disease Good uses -fermentation -waste management -Toxic clean-up -Genetic engineering -antibiotics Archaea share traits with bacteria and eukaryotes Extreme halophiles- highly saline environments Extreme thermophiles- very hot environments Methanogens- produce methane as a waste product -anaerobes 1/29 Protists- unicellular eukaryotes -more diverse than any other group -have organelles -more complex than prokaryotes -Some are colonial and multicellular -more closely related to plants, fungi and animals than they themselves Nutritionally diverse. Can be… -Photoautotrophs -Heterotrophs -Mixotrophs Protists can reproduce sexually or asexually Protist diversity has origins in endosymbiosis Mitochondria evolved by endosymbiosis of an aerobic prokaryote Plastids evolved by endosymbiosis of a photosynthetic cyanobacterium -plastid-bearing lineage of protists evolved into red and green algae. Then red and green algae underwent secondary endosymbiosis There are 5 super groups of Eukaryotes Excavata, chromalveolata, archaeplastidia, rhizaria, unikonta 1. Excavata -Feeding group characterized by cytoskeleton Diplomonads -have mistosomes -parasites Giardia Parabasalids -have hydrogenosomes -Trichomonas vaginalis-pathogen that causes yeast infections Euglenoza -diverse clade with a rod of unknown function in flagella -kinetoplastids have a single mitochondria 2. Chromalveolata -monophyletic and orginated by secondary endosymbiosis with red algae Superphylum Alveolata- membrane bound sacs called alveoli just under plasma membranes Dinoflagellates -aqutic mixotrophs and heterotrophs -reinforced by internal plates of cellulose -cause of red tides Phylum Apicomplexa -parasites of animals -apex has organelles specialized for penetrating host -sexual and asexual stages -plasmodium parasite that causes malaria Phylum Stramenopila -Diatoms-unicelluar algae with 2 part wall of hydrated silicia Golden algae -Unicellular, some are colonial -yellow and brown carotenoids Brown algae -largest and most complex algae -mulitcellular and most are marine -body is plantlike but it is called a thallius -root like holdfast anchors the stem like stipe which supports leaf like blades 3. Rhizaria -monophyletic clade -amoebas move and feed by pseudopodia -include forams and radiolarians -both have hard shells and tests. Pseudopodia extend through holes in the test 4. Archaeplastida -red and green algae and land plants -heterotrophic protists acquired a cyanobacterial endosymbionts -photosynthetic descendants evolved into red and green algae -Land plants are descended from green algae Red Algae -multicellular -largest seaweeds -red due to accessory pigments Green algae -2 groups, the chlorophytes and charophyceans -most in fresh water -others live in damp soil and snow 5. Uniknots -includes animals, fungi and closely related protists