Biological Diversity notes for exam 3
Biological Diversity notes for exam 3 BSCI 10110
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This 8 page Class Notes was uploaded by Brittany Yee on Wednesday April 6, 2016. The Class Notes belongs to BSCI 10110 at Kent State University taught by Dr. Mark W. Kershner in Spring 2016. Since its upload, it has received 24 views. For similar materials see Biological Diversity in Biological Sciences at Kent State University.
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Date Created: 04/06/16
CH 28 PROKARYOTES Prokaryotes have 2 domains: o Archaea o Bacteria Lack a membrane bound nucleus Date back at least 3.8 bya o During anoxic period (time when universe was not filled with oxygen), found fossils or filamentous, rod shaped morphology similar to modern bacteria o Analysis of the fossils shows evidence of carbon fixation and membrane lipids Carbon fixation is important because its something that living things do Carbon Fixation- conversion of inorganic carbon to organic carbon Basic forms: o Spiral, spherical (coccoid), and rod-shaped Aggregated: filaments Shared across bacteria and archaea Most comparisons depend upon biochemical/chemical differences o The issue here is that we can only culture about 1% of prokaryote diversity. Prokaryotes have to be able to be cultured to compare them DIFFERENCES BETWEEN BACTERIA AND ARCHAEA Bacteria Archaea Bonds Ester bonds between Ether bonds in their cell glycerol and fatty acid membranes. Ether bonds tails in their cell are much more stable membranes than ester bonds and don’t break down easily under extreme environmental conditions - Allows them to survive extreme conditions that would kill most bacteria Cell wall Peptidoglycan Lack peptidoglycan, so (carbohydrate polymer) is they have to be a major structural separated from a component different method than - Is so important that bacteria it’s a way to distinguish between different types of bacteria via gram staining Genetic machinery Have a unique system Explains why archaea are associated with protein that’s much more simple closer related to production* - Completely lacks eukaryotes than bacteria exons and introns - Same system as that alter the eukarya expression of a - Exons/introns- given gene presence of these genetic structures alters gene expression which alters protein production DOMAIN ARCHAEA Found everywhere, but primarily associated with extreme conditions o Acidic/basic environments, different chemical conditions, high/low temps, etc Because of this, archaea are referred to as extremophiles No known Archean parasites or Archean pathogens (archaea that cause disease) There are archaea that are symbiotic- which means that one organism is benefitting directly and the other organism is either benefitting or is not affected o 2 major types of symbionts: 1.) commensal symbiosis- (+/0) one organism benefits and the other organism is neither hurt or helped by the relationship 2.) mutualistic symbiosis- (+/+) both organisms benefit from the relationship of the two TYPES OF ARCHAEA Thermophiles- high temperature conditions (60-80 C; 140-175 F) o Due to the fact that they have heat stable enzymes o Have strong cell membranes with ether bonds that can withstand the heat o Habitat can be hot springs, geysers o Thermal vents o Types of Thermophiles: Pyrococcus furiosus- optimal growth when T= 100 C enzymes have tungsten, which has a high melting point, which stabilizes enzymes at extremely high temperatures Thermus aquaticus- has heat stable enzymes Has enzyme called Tag polymerase- which is used in polymerase chain reactions (PCR) which is a critical tool in modern genetics. It is used to take a single piece of DNA and amplify it to millions of copies of it Acidophiles- found in areas with low pH (high acidity, ≤ 20) o Found in acidified environments (bogs, pine forests) o Acid mine drainage o Found in food products (yogurt, buttermilk, sour cream) o Are able to block the proton uptake There are lots of protons in acidic conditions and if you take them up they will ultimately kill you Halophiles- Archeans that can handle high salinity environments o optimal growth at 40% salinity o commonly found in areas like the dead sea, great salt lake o found in foods such as sauerkraut, soy sauce, any highly saline food o * have the capacity to block salt uptake and block water loss o Have a biotechnical use- taking the genes of halophiles that are associated with the ability to grow in areas of high salinity and genetically engineer it into genomes of crop plants Allows crops to grow/produce food in soils that are high in saline content Methanogens- Archeans that produce a lot of methane (major greenhouse gas) as part of their biological process o Live in the intestines of many organisms(humans, cows) Get out through flatulence or burping o Also found in wetlands/swamps, trash and garbage dumps (which produce an extremely high rate of methane), termite digestive tracks DOMAIN BACTERIA Diversity is poorly understood Most basic way to identify groups is to analyze their cell wall structure through gram- staining o Gives information about the environmental tolerances o Gram – bacteria are more tolerant to environmental tolerances than gram + o Gain info about response to toxins, medications o Insight into food/nutrient preferences DIFFERENCES BETWEEN GRAM + AND GRAM – Most differences are with how they stain and their cell wall Gram (+)- first steps in staining protocol separate into this group o Cells turn purple o Have a thick cell wall that is loaded with peptidoglycan (which is lacking in archaea) It’s the peptidoglycan that stains purple o Thick cell wall Gram (-)- contain less peptidoglycan (a thin layer) o do not retain purple colored dye o can be stained with a red counterstain and then appear dark pink o have 2 layers inner layer- thin sheet of peptidoglycan outer layer- typical lipid membrane o liposaccharides- recognition of food, toxins, stores organisms o porin- protein that determines what goes in/out of the cell bilayer cell wall- much better at determining what goes in/out of the cell wall o is much less susceptible to antibiotics GRAM – BACTERIA Ph. Cyanobacteria o Also known as “blue-green algae” Produce toxins to reduce the likelihood that they will be eaten o They are photosynthetic- autotrophs Use sunlight and inorganic CO 2or energy/metabolic needs to increase growth and reproduction o They are Nitrogen fixers. They convert atmospheric nitrogen (N ) into ammonia 2 This is important because nitrogen is inaccessible to other forms of life (it’s a limiting resource), and the ability to take it and turn it into something you can use is extremely important o Most common form of cyanobacteria is Microcystis- which creates HAB’S They produce a toxin called microsystin which is very harmful if ingested by humans Very common o Common soil bacteria o Associated with plants roots o Form nodules (swelling) on plant roots o Mutualism (+,+) [symbiosis] Means that both organisms benefit Phylum Proteobacteria o Largest, most diverse phylum o Found everywhere o They are extremely diverse when it comes to their physiological characteristics, meaning they can handle a lot of different environmental factors and have broad environmental tolerances o They are grouped based upon their physiological characteristics Groups include alpha, beta, gamma, e.t.c. each possessing different physiological characteristics * Will need to know about the different type of bacteria for the exam Groups of proteobacteria: 1.) Escherichia Coli (E. Coli)- Found in mammalian digestive systems Are very common in sewage and polluted water primarily from human feces o Fecal coliforms- E. Coli that are found in water sources Is the best studied of all bacteria o Huge genomic diversity. They extraordinarily genetically diverse Helpful strains (in digestive system) and harmful strains (example – E. Coli 0157:H7) o E. Coli 0157:H7- associated with undercooked meat or contaminated vegetables or fruit. Harmful to human systems because they produce toxins and the infection moves very quickly. Can kill within a week 2.)Wolbachnia Species o The “male killer” in reproductive cells o Intracellular bacteria- they live in egg cells within the female o As of right now, only found in insects, and 25-35% of all insects have it. It is inherited* Mechanisms: Kills males in utero (before they’re even born so that only females are born) Can also feminize males. They are sterile and they take on the various behaviors of females Can convert males into true females that can give birth How production without a viable male works: Pathogenesis- “Virgin birth” No male genetic input. Produces clones of the female o Is being used to decrease malaria outbreaks because mosquitos with Wolbachia are resistant to carrying malaria 3._Heliobacter Pylori o Associated with gastrointestinal Tract Survives stomach acid Has a corkscrew flagellum, which is useful for burrowing into the stomach lining o Cause gastritis – ulcers Ulcers can lead to stomach cancer Discovered by Barry Marchall 4.) Yersinia Pestis o Associated with “black plague” o Easily treated with antibiotics o Carried by fleas and rats Flea infected with Yersinia pestis Leads to a blocked digestive system Results in no nutrients from food increased biting because they’re starving bite rats which are closely associated with humans results in plague conditions o There are 3 forms of the plague: 1.) attach to lymph nodes- leads to swelling “bubos” bubonic plague 2.) Septicemic/ blood form- blackening of tissue due to blood vessel hemorrhages Black plague 3.) Geobactor metallireducens- breaks oil down to harmless by-products (particularly carbon dioxinde) Also used to clean up oil spills and uranium Bioremediation PROKARYOTE REPRODUCTION types No sexual reproduction- no fusion of male and female gametes Strictly asexual reproduction o Binary fission- single cell goes through the process of binary fission First step is to replicate the DNA 2.) individual bacterium begin to split and divide into 2 cells Results in 2 daughter cells which can also undergo binary fission One cell splits into two, two cells split into four, and so on Horizontal gene transfer- exchange of genes, often* among bacterial cells o Genes can be taken up in 2 ways: 1.) incorporated into the genome of the bacteria 2.) Exist as a plasmid within the cell Plasmid- a small DNA molecule that is separate* from the genome o Replicates when cell goes through binary fission Conjugation- Transfer of plasmids from one bacterium to another o Plasmids associated with antibiotic resistance, virulence, toxin production o Transferred on a pilus- a conjugation bridge Transduction- associated with accidents during lytic cycle of a viral infection o *E. Coli 0157: H7 has been both conjugation and transduction Transformation- DNA from a dead bacterial cell is taken up by a living cell and incorporated into the genome just how it was with transduction PROKARYOTE METABOLISM There is no growth or reproduction without energy and carbon Autotrophs- get their carbon from inorganic CO 2 Type of autotroph Get energy from Get Carbon from Photoautotrophs Sunlight Inorganic CO 2 Chemoautotrophs -Molecular compounds Inorganic CO 2 -rocks and minerals -oxidation of inorganic molecules Heterotrophs- get their carbon from organic sources (carbon sources that are usually produced by other organisms) o Examples of organic sources include glucose, sugars, carbohydrates and alcohols Type of Heterotroph Get energy from Get Carbon from Photoheterotroph Sunlight Organic carbon Chemoheterotrophs Oxidation of organic Organic carbon molecules o Most prokaryotes and non-synthetic eukaryotes are chemoautotrophs Mixotrophs- can use autotrophy or heterotrophy CH 29 PROTISTS Are Eukaryotes- have a membrane bound nuclei and other membrane bound organelles 1.5 billion years old o Similar to green algae A very diverse group and is referred to a “catch all” group, which is for organisms that don’t fit in other taxonomic groups Have multiple independent evolutionary lineages o Means they don’t necessarily have a common ancestor * there are no characteristics unique to ALL protists Protist metabolism (Energy and Carbon) o Autotrophs- (photo/chemolitho) get Carbon from inorganic CO 2 o Heterotrophs- gain carbon and energy from external sources DIVERSITY AND EVOLUTION Changes responsible for evolutionary changes. All starts among the protists o ProkaryoticEukaryotic o Asexual sexual reproduction o Unicellular multicellular ENDOSYMBIOTIC THEORY Endosymbiosis- organisms living together for mutual benefit o Explains the transition from prokaryotes to eukaryotes o Starts when a bacteria is living within a bacteria and evolves into mitochondria and chloroplasts WHO ARE THE PROTISTS They are massively important in food webs They are at the base of most aquatic food webs and without them most of these food webs would actually collapse o Includes kelp, algae, “seaweed” There are major pathogens (diseases causers) within this group. Protists are the number one killer in the world o Malaria, African sleeping sickness There are major Oxygen producers in this group as well and they are typically referred to phytoplankton o Produce 80% of the worlds oxygen o Include algae and diatoms They are critical decomposers- they break down organic matter physically and chemically Finally, they are mainly aquatic o Includes marine and fresh water systems as well as blood and other bodily fluids AQUATIC AUTOTROPHIC PROTISTS Phytoplankton- “floating plants” o Are NOT actually plants o They are photoautotrophic and rely on photosynthesis Photosynthesis equation- CO + 2 O +2light O + o2ganic food o Commonly found in large groups called blooms Blooms result from very good growing conditions, meaning there is a good availability of Nitrogen and Phosphorus which allows them to grow very quickly o Multi species assemblages (Prokaryotes can be a part of this group as well) Both algae and cyanobacteria (prokaryotes) Algae = green algae (chlorophyla) and diatoms o Green Algae- Autotrophs Unicellular- single cell filaments, colonies Unicellular phytoplankton There are some with multicellular forms that are NOT phytoplankton o Diatoms- autotrophs. Hugely important in the atmosphere’s Oxygen budget As a group, are the largest, most abundant type of phytoplankton Are strictly unicellular- single cells, colonies Have floating forms (which are the phytoplankton) Also have attached forms which are NOT the phytoplankton because they are not floating Ex of attached diatoms: the film you see on dirty fish tanks The individual protists of diatoms have the ability to form intricate, complex structures (shells) that encase the individuals themselves. An individual protest diatom has 2 cells Frustules- shells secreted by the protest, composed of calcium and silica o When diatoms die, the frustules lay on the bottom of the lake or the ocean. The frustule fossils are very sensitive to environmental conditions and are important for reconstruction of ancient environmental conditions. This is possible because individual diatom species have very specific environmental tolerances relative to things such as acidity, salinity, nutrients, or temperature o Diatoms and green algae are the primary components of phytoplankton o Dinoflagellates- all possess two flagella The flagella are for movement and foraging Floating forms- phytoplankton Attached forms- living in a mutualistic relationship with coral As a group, most of them are mixotrophs Examples of dinoflagellates- they cause red tide (toxic phytoplankton bloom), bioluminescence, coral symbionts, pfesteria- highly toxic dinoflagellates that cause massive amounts of fish deaths AQUATIC HETEROTROPHIC PROTISTS Chanoflagellates- are predators that feed on phytoplankton, prokaryotes o As a group, are highly mobile and unicellular o Are all unicellular but can be single or colonial o Are highly mobile and possess 1 flagella o Are not photosynthetic in any way, so are chemoheterotrophs Attached aquatic autotrophic protists Along with floating phytoplanktonic protists, there are also attached aquatic autotrophic protists as well o They are non mobile o Found in both marine and fresh water environments 3 types: o 1.) Green algae- multicellular Freshwater green algae- Chara Ulva- sea lettuce, marine green algae