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29topic_4_f07 - Topic 4 Evolution of Organisms History of...

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Unformatted text preview: Topic 4 Evolution of Organisms History of Classification Early History Aristotle Tried to group animals according to mode of reproduction and presence or absence of red blood. blood Trained in dissection he studied many species History of Classification Early History Theophrastus (372-288 BC), "the father of botany" Student of Aristotle, continued his work 2 major treatises on plants Studied over 500 species of cultivated plants Saw the study of plants as a form of knowledge Introduced new terms and laid the foundation for the subsequent development of herbals Carlos Linnaeus and the binomial system of nomenclature Prior to Linnaeus there was a polynomial system often with a lot of variability from one place to the next. Also the use of common names was most prevalent and confusing Plants were named according to medicinal use. Carlos Linnaeus and the binomial system of nomenclature Linnaeus lived in a time of world wide exploration where plant collecting was common. His system gives each plant a single name composed of a genus and a specific epithet. The species is the combination of the genus and the specific epithet Carlos Linnaeus and the binomial system of nomenclature As an example, the Pin Oak tree is in: the genus Quercus and has the specific epithet palustrus making the species name Quercus palustrus. palustrus Charles Darwin:the Theory of Evolution Darwin Lived in a time of scientific exploration in which intellectuals were broadly educated Was aware of the works of Malthus and the geologist Lyell Took a long voyage on the HMS Beagle with captain Fitzroy around the to the Pacific Ocean and the Made observations on geological strata and on various species including finches Charles Darwin:the Theory of Evolution Darwin is based on 5 key observations. observations Species have great fertility and make more offspring than can achieve adulthood Populations remain relatively constant with some fluctuation Food is a limiting factor although the supply is relatively constant. There is always a struggle for food In sexually reproducing species there is a large amount of variation Much of variation is inheritable 18 and 19 Centuries Charles Darwin:the Theory of Evolution Darwin has two basic parts. Evolution, which he called "descent with Evolution modification" is the process. process Natural selection of the most fit organisms is the mechanism for the process of evolution A good website: http://en.wikipedia.org/wiki/Charles_Darwin The Hardy-Weinberg theorem describes a non evolving population. Large population Isolation No net mutations Random mating No natural selection Factors which contribute to evolution in a population Genetic drift Natural selection due to environmental changes The bottleneck effect A founder population The 20 and 21 Centuries Gould and Eldridge propose the theory of punctuated Gould Eldridge equilibrium That species accumulate a number of neutral mutations When the number of neutral mutations reaches a critical mass change occurs That there are periods of great change brought on by extreme changes in the environment Kingdoms and Domains 2-3 kingdoms Initially there were only animals and plants In 1866 Ernst Heinrich proposed a third kingdom, the protista that included protozoa, algae, fungi and bacteria Kingdoms and Domains Whittaker's 5 kingdoms He based his classification on: A separation of the prokaryotes from the eukaryotes, putting the prokaryotes in the Monera The other four kingdoms are created on the basis of: Mode of nutrition (this was Whittaker's Life cycle Structure primary distinction) Kingdoms and Domains Whittaker's 5 kingdoms These four kingdoms are: nutritional modes ingestors Protista unicellular, diverse Animalia heterotrophic, Fungi saprophytic Plantae photosynthetic autotrophs Kingdoms and Domains Five Kingdoms Monera Protista Plantae Fungi Animalia Kingdoms and Domains Two Kingdoms of Monera Monera Eubacteria Archaebacteria Kingdoms and Domains Dividing Protista into 3 Kingdoms Protista Archezoa Protista Chromista Eight Kingdoms Prokaryotes Eubacteria Archaebacteria Eukaryotes Archezoa Protista Chromista Plantae Fungi Animalia Kingdoms and Domains Three Domains Eubacteria Archaebacteria Eukaryota The Endosymbiotic Theory Lynn Margulies While at Boston University, Margulis proposed a radical idea, endosymbiotic theory. The endosymbiotic theory is a suggestion of how organelles came into being. Her theory suggests that maybe an oxygen breathing bacteria was eaten, or ingested, by an anaerobic bacteria that had amoeba-like features. These two bacteria features worked together, mutually benefiting from each other's functions. The aerobic bacteria breathed for the anaerobic bacteria, while the anaerobic bacteria directed them through the waters in a hunt for food. The Endosymbiotic Theory Lynn Margulies The Endosymbiotic Theory Lynn Margulies After the proposal of the endosymbiotic theory, Margulis predicted that if organelles were prokaryotic symbionts, then the organelles will have their own DNA that would be different from the DNA of the cell. cell This prediction was actually proven in the 1980's in mitochondria, centrioles, and chloroplasts. The Endosymbiotic Theory Lynn Margulies For many years, Margulis was criticized and ridiculed for her "radical" thinking. However, Margulis pursued onward, which lead to the general acceptance of her theory. users.rcn.com/jkimball.ma.ultranet/BiologyP ages/E/Endosymbiosis.html www.immaculata.edu/bioinformatics/ esehi/lynn%20margulis.htm The Endosymbiotic Theory Evidence Both mitochondria and chloroplasts can arise only from preexisting mitochondria and chloroplasts. They cannot be formed in a cell that lacks them because nuclear genes encode only some of the proteins of which they are made. The Endosymbiotic Theory Evidence Both mitochondria and chloroplasts have their own genome and it resembles that of prokaryotes not that of the nuclear genome. Both genomes consist of a single circular molecule of DNA. There are no histones associated with the DNA. The Endosymbiotic Theory Evidence Both mitochondria and chloroplasts have their own protein-synthesizing machinery, and it more closely resembles that of prokaryotes than that found in the cytoplasm of eukaryotes. The first amino acid of their transcripts is always fMet as it is in bacteria (not methionine [Met] that is the first amino acid in eukaryotic proteins). The Endosymbiotic Theory Evidence A number of antibiotics (e.g., streptomycin and chloramphenicol) that act by blocking protein synthesis in bacteria also block protein synthesis within mitochondria and chloroplasts. They do not interfere with protein synthesis in the cytoplasm of the eukaryotes. The Endosymbiotic Theory Evidence Conversely, inhibitors (e.g., diphtheria toxin and cycloheximide) of protein synthesis by eukaryotic ribosomes do not -- sensibly enough -- have any effect on bacterial protein synthesis nor on protein synthesis within mitochondria and chloroplasts. The Endosymbiotic Theory Evidence The antibiotic rifampicin, which inhibits the RNA polymerase of bacteria, also inhibits the RNA polymerase within mitochondria. It has no such effect on the RNA polymerase within the eukaryotic nucleus. The Hierarchy of Taxonomic Organization Kingdom Animalia Plantae Angiospermae Magnoliophyta Rosales Rosaceae Prunus serrulata Flowering cherry Phylum/Division Chordata Class Order Family Genus Specific epithet Common name Mammalia Carnivora Felidae Panthera pardus Leopard The Hierarchy of Biological Organization Atom Molecule Organelle Cell Tissue Organ Organism C, H, O, N,P,S, Fe, Mg Organic Acids, Lipids, Proteins, Nucleic Acids, Carbohydrates Nucleus, Chloroplasts, Mitochondria, ER, Golgi Guard Cells, Tracheids, Sieve Tube Elements Epidermis, Mesophyll, Xylem, Phloem Leaves, Roots, Stems, Flowers Algae, Mosses, Ferns, Pine Trees, Maple Trees, Cannabis sativa ...
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