Biology Lecture

Biology Lecture - Biology Lecture #1 (Chapter 14)...

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Unformatted text preview: Biology Lecture #1 (Chapter 14) 23/10/2007 15:34:00 o Classifying the Diversity of Life The Linnaean Classification System o Carolus Linnaeus: Swedish Biologist- 1750s o First person to try and bring order to life o Binomial system for species name aka scientific name two part Latin name for one sp. Genus (group) + specific epithet EX: Homo Sapiens (humans) o The Hierarchical classification system taxonomy= putting organisms into groups (= taxa ) a man-made construct may/may not reflect common descent groups of lower taxa from higher taxa all species in any taxon share certain features Fig. 14.21 learn the taxonomic levels (from most inclusive to least inclusive) Domain Kingdom Phylum Class Order Family Genus Species Phylogenetic Trees phylogeny = the evolutionary history of a species and its relationship to other spp. often based on lots of info (fossils, anatomy, etc.) not proven (hypothesis) objective: each taxon should include only and all species with a common ancestor Cladistics Determines phylogeny based on shared heritable features (homologies) Homologies are assumed to be derived from common ancestor Clade = branch of cladogram Members of each clade share homologies Biology Lecture #2 (Chapter 15) Evolution 23/10/2007 15:34:00 o Overview of History of Life See posting on website and learn sequential order of events listed o Prokaryotes Earliest form of life o Prokaryotic Structure and Function No nuclear envelope, no membrane-bound organelle 3 shapes o rods (bacilli) o spheres (cocci) o helical (spirochetes) Almost all are unicellular o But some form simple colonies Many are mobile, w/ flagella o Domain Bacteria Most abundant organisms on earth o Reproduce rapidly by binary fission (asexual) Many can survive harsh conditions by forming into resistant endospores o EX bacteria that cause anthrax, botulinism Bacteria nutritional diversity o Most are absorptive heterotrophs Absorptive= dissolved materials pass through plasma membrane Heterotrophic= uses organic matter as both carbon and energy source Some are anaerobic (= must have no oxygen!) Some do aerobic cellular respiration just like mitochondria (requires O 2 ) o Many are photoautotroph = uses CO2 as carbon source + light energy source cyanobacteria do photosynthesis just like plants (make huge % of earths oxygen today) original source of O2 in air in history of earth Bacteria and Symbiosis o = two species living in close relationship o Parasitism- smaller parasite benefits at the expense of the other...
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Biology Lecture - Biology Lecture #1 (Chapter 14)...

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