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Classification of organisms. Kingdoms: Eubacteria, Archaebacteria, Protist and Fungi. Taxonomy. A systematic method of classifying plants and animals. Classification of organisms based on degrees of similarity representing evolutionary (phylogenetic) relatedness. Scientific Names.
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Classification of organisms Kingdoms: Eubacteria, Archaebacteria, Protist and Fungi
Taxonomy • A systematic method of classifying plants and animals. • Classification of organisms based on degrees of similarity representing evolutionary (phylogenetic) relatedness.
Scientific Names • Binomial nomenclature (Linnaeus) • A 2 name system so that not two organisms will ever have the same name. • The genus name is combined with a second name to make the species name unique. • For example: humans • GenusHomo • SpeciesHomosapiens
Human classification • Kingdom Animalia • Phylum (Division for plants) Chordata • Class Mammalia • Order Primates • Family Hominidae • GenusHomo • SpeciesHomosapiens
Levels of classification • King Philip chews on funny ginger snaps CLASS KINGDOM ORDER PHYLUM FAMILY GENUS SPECIES SMALLEST LARGEST
Kingdom Phylum (Division for plants) Class Order Family Genus Species • Each level has more and more similarities!
6 Kingdoms heterotroph autotroph heterotroph autotroph heterotroph autotroph heterotroph
Viruses • Viruses are NOT one of the 6 kingdoms and are not considered “alive” because they are not made up of cells, do not metabolize, can only reproduce inside another living cell and do not grow. • They are studied because they infect living cells and cause disease. • Things that cause disease are known as pathogens!
Viruses: a Group of Intracellular Parasites • A virus is a submicroscopic infectious particle composed of a protein coat and a nucleic acid core. • Viruses, like cells, carry genetic information encoded in their nucleic acid, and can undergo mutations and reproduce; however, they cannot carry out metabolism, and thus are not considered alive. • Viruses are classified by the type of nucleic acid they contain, and the shape of their protein capsule.
adenovirus The Adenovirus is a DNA virus that causes colds and "pink eye".
The Influenza virus causes the flu. It has RNA as its genetic material instead of DNA.
Bacteriophages invade the host cell, take over the cell, and begin replicating viruses, eventually lysing or bursting the host cell, releasing the new viruses to infect additional cells.
Retroviruses • Retroviruses have RNA and the enzyme reverse transcriptase instead of DNA as their nucleic acid core. • Once inside the host cell, reverse transcription (making DNA from RNA) is accomplished by the reverse transcriptase, turning the single-stranded RNA into DNA. This new DNA is incorporated into the host DNA, where it transcribes new viral RNA genomes, as well as the RNA to synthesize new reverse transcriptase and protein capsules.
Viruses are usually quite specific as to their hosts and even to the types of cells they infect in a multicellular host. • Viruses can NOT be treated with antibiotics because antibiotics are designed to attack the cell wall or membrane and viruses do not have these!
Viroids and Prions • Viruses would appear to be the simplest form of infectious particle. • The discovery of viroids, nucleic acid without a protein capsule and prions, infectious proteins, subtracts another level of complexity. • Both viroids and prions can cause diseases.
How a virus invades your body! • http://www.npr.org/blogs/krulwich/2009/10/23/114075029/flu-attack-how-a-virus-invades-your-body?sc=emaf
Archaebacteria • Prokaryotic • Unicellular • Autotroph/ heterotroph
Archaebacteria • The most primitive group, the archaebacteria, are today restricted to marginal habitats such as hot springs or areas of low oxygen concentration. Three types of Archaebacteria: methanogens, halophiles, and thermacidophiles. They live in extreme habitats like very salty water! prokaryotes
Organisms in this group lack membrane-bound organelles associated with higher forms of life. Such organisms are known as prokaryotes. • Their small size, ability to rapidly reproduce (E. coli can reproduce by binary fission every 15 minutes), and diverse habitats/modes of existence make bacteria the most abundant and diversified kingdom on Earth.
Bacteria occur in almost every environment on Earth, from the bottom of the ocean floor, deep inside solid rock, to the cooling jackets of nuclear reactors.
Rod-Shaped ( Bacillus) Bacterium, hemorrhagic E. coli, strain 0157:H7
Scanning electron micrographs illustrating external features of the rod-shaped bacterium E. coli.
Coccus round-shaped Bacterium (causes skin infections), Enterococcus faecium
Left, a cross-section of a cell illustrating the location of a flagella inside the cell; Center, Borrelia burgdorferi, the organism that causes Lyme disease; and Right, Treponema pallidum, the spirochete that causes the venereal disease syphilis. The image above is from http://www.bact.wisc.edu/Bact303/MajorGroupsOfProkaryotes.
Endospores • are a method of survival, not one of reproduction. Certain bacteria will form a spore within their cell membrane (an endospore) that allows them to wait out deteriorating environmental conditions. • Certain disease causing bacteria (such as the one that causes the disease Anthrax) can be virulent (capable of causing an infection) 1300 years after forming their endospores
Evolution of Eukaryotes • The transition to eukaryotic cells appears to have occurred during the Proterozoic Era, about 1.2 billion years ago. However, recent genetic studies suggest eukaryotes diverged from prokaryotes closer to 2 billion years ago. Fossils do not yet agree with this date.
PROTISTSeukaryoticunicellular/ some multiheterotrophic and autotrophic
Classification of Protists • The protists include heterotrophs, autotrophs, and some organisms that can vary their nutritional mode depending on environmental conditions. • Protists occur in freshwater, saltwater, soil, and as symbionts within other organisms. • Due to this tremendous diversity, classification of the Protista is difficult.
Protozoa: Single-Celled, Motile Organisms • This group of protists are single-celled, motile, heterotrophs. • Most digest their food by vacuoles formed by phagocytosing other organisms (bacteria or other single-celled creatures). • Reproduction varies greatly, from a binary fission-like process to true meiosis. • The main distinguishing feature is the method of locomotion: flagella, cilia, or pseudopodia.
Amoeboid Protozoa Use Pseudopods for Movement • Amoeba and Pelomyxa move by extensions of their cytoplasm known as pseudopodia.
Foraminifera • live in the oceans and secrete a shell (also known as a test) composed of silica or calcium carbonate. • Thus, the fossil record of forams is quite good. Oxygen isotope data from forams has been used to calculate ocean temperature fluctuations over the past 100,000 years.
Sporozoans • Members of this group cause malaria and toxoplasmosis. • Toxoplasmosis is transmitted from cats to humans, with between 7 and 72% of the population infected, depending on the geographic area.
Malaria • infects an estimated 300 million people, and is spread by mosquitoes, transfusions, and shared hypodermic needles. • Infected individuals can be treated with a variety of medicines. However, some of the sporazoans that cause malaria have developed immunity to some of the more commonly employed medicines.
Ciliates • Ciliates are complex, heterotrophic protozoans that lack cell walls and use multiple small cilia for locomotion. • To increase strength of the cell boundary, ciliates have a pellicle, a sort of tougher membrane that still allows them to change shape. • Most of the 8000 species are freshwater. Most ciliates have two nuclei: a macronucleus that contains hundreds of copies of the genome and controls metabolisms, and a single small micronucleus that contains a single copy of the genome and functions in sexual reproduction.
Paramecium Showing cillia
