Exam 2 Study Guide
Exam 2 Study Guide BIOL 106
Minnesota State University, Mankato
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This 7 page Study Guide was uploaded by Mallory Eberspacher on Monday October 10, 2016. The Study Guide belongs to BIOL 106 at Minnesota State University - Mankato taught by Dr. Matthew Kaproth in Fall 2016. Since its upload, it has received 82 views. For similar materials see General Biology II in Biology at Minnesota State University - Mankato.
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Date Created: 10/10/16
Exam 2 Study Guide Ch. 18 Evolution and the Origin of Species Darwin’s “Theory of Evolution” Evolution itself is not the theory Evolution was already accepted by many scientists before Darwin How evolution occurred was not understood before Darwin’s time The mechanism for evolution, Natural Selection, is the theory Evolution—A heritable change in one or more characteristics of a population or species over many generations Population—group of individuals of one species that live in the same geographic area at the same time Inheritance of acquired characteristics Darwin’s theory—natural selection or genetically-based variation leads to evolutionary change Lamarck’s theory—acquired variation is passed on to descendents Charles Darwin 5 yr. voyage on the Beagle 2 important observations Natural Selection—Reproduction of individuals with favorable traits that survive environmental change because of those traits 3 principles: 1. Individuals in a pop. vary in traits 2. Traits can be heritable 3. Species w/certain traits can survive and reproduce at higher rates than those w/o those traits Divergent Evolution—When two species evolve in diverse directions from a common point Convergent Evolution—Where similar traits evolve independently in species that do not share a common ancestor Evidence of Evolution 1. Fossils 2. Anatomy a. homologous structures (homology)—similar structures in diverse organisms that have a common ancestor b. analogous structures (analogy)—structures of different species having similar function but not from same origin Species—group of organisms consisting of similar individuals capable of exchanging genes or interbreeding Speciation—Formation of two species from one original species Allopatric Speciation Sympatric Speciation Species Concepts: 1. Morphological 2. Biological 3. Ecological 4. Phylogentic Reproductive Isolation Mechanisms: Prezygotic isolating mechanism—prevent formation of zygotes o Factors: geographic isolation ecological isolation behavioral isolation temporal isolation mechanical isolation prevention of gamete fusion Postzygotic isolating mechanism—allow zygotes to form but prevent or inhibit their normal development into reproducing adults Ch. 19 Evolution of Populations Gene—physical and functional unit of heredity Chromosome—made up of nucleotides; humans have 23 sets of homologous chromosomes Genotype—combination of alleles Phenotype—physical expression of genes Gene Pool—possible alleles that can be donated Allele frequency Genotype frequency Hardy-Weinberg Principle—allows prediction of genotype frequencies 5 assumptions: 1. No mutations 2. No migration 3. Random mating 4. Large Population Size 5. No selection Allele equation: p+q=1 Genotype equation: 2 2 p +2pq+q =1 5 Agents of Evolutionary Change: 1. Mutation 2. Gene Flow 3. Nonrandom Mating i. assortive mating, disassortative mating, inbreeding 4. Genetic Drift i. founder’s effect, bottleneck effect 5. Selection Maintenance of Variation: Negative frequency-dependent selection Positive frequency-dependent selection Heterozygote advantage Types of selection (also know graphs/figure associated with each type) Disruptive selection Directional selection Stabilizing selection Cline—gradient of environmental condition; directional selection Ch. 20 Systematics, Phylogenies, and Comparative Biology Systematics—organizing and classifying organisms based on evolutionary relationships 3 main parts: 1. Taxonomy 2. Phylogeny (family trees) 3. Study of the process of evolution Classification system: hierarchical Domain: Bacteria, Archaea, Eukarya (Supergroups) Kingdom: Plantae, Animalia, Fungi Phylum Class Order Family Genus Species Branching Diagrams Cladistics o Clade= a grouping of relatives (and common ancestor) Ancestral vs. Derived Characters Shared derived characters and Shared ancestral characters Homoplasy—a character shared by a set of species but not present in their common ancestor Principle of Parisomy—most likely that an event occurred once and in the most simplest or economical way The Origin and Diversity of Life Origin of the Universe Big Bang—13.7 BYA Solar system—4.6 BYA Earth—4.5 BYA Origins of Life organisms share fundamental properties of life o H, O, N, C life arose from small organic molecules how did organic molecules “find their way” to Earth? Life: carbon based water based nucleotides replication 4 Stages in Chemical Evolution of Life 1. Formation of small organic molecules 2. Small organic molecules formed polymer 3. Polymers were enclosed in membranes 4. Polymers + membranes developed cellular properties Components of reducing atmosphere Miller-Urey Experiments (1950s) Early Life on Earth First cells probably aquatic anaerobic heterotrophs First organisms to populate Earth were prokaryotes Atmosphere of Early Earth less oxygen strong volcanic activity strong radiation Stromatolites—colonies of cyanobacteria layered with calcium carbonate to form rock-like columns Examples of changes in Earth’s environment that affected organisms: climate/temp. land masses atmosphere natural disasters Ch. 22 Prokaryotes 3 Domains: 1. Bacteria—no nucleus, auto/heterotrophs 2. Archaea—no nucleus, auto/heterotrophs 3. Eukarya—nucleus, Protista, animalia, fungi, plantae Domain Archaea Similarities and differences from bacteria Extremophiles—Archaea that are adapted to grow under extreme conditions o examples of extremophiles and their environmental capabilities of growth Methanogens—organisms that live off of methane Domain Bacteria examples: o gram-positive/gram-negative bacteria, etc. Prokaryotic Cell Structure Motility o flagella and pili Size—0.5 to 1.0 micrometer in diameter Shapes o Coccus—capsule-like o Bacillus—rod-like o Spirillum—spiral-like Cell arrangement o unicellular o ex: cyanobacteria show variability Cell wall Endospore o hardened membrane that let bacteria become dormant in harsh environments o “resting cells” o non-reproductive Reproduction of Prokaryotes Asexual reproduction (binary fission) Conjugation o recombination of genes Prokaryotic Metabolism autotrophs o require CO 2 o photoautotrophs and chemolitho(auto)trophs (nitrifiers or oxidizers) heterotrophs o C from organic sources o photoheterotrophs and chemoheterotrophs (decomposers) Respiration Aerobic respiration—need oxygen Anaerobic respiration Plant Pathogen Examples Animal Pathogens diseases in animals and humans Beneficial Prokaryotes role in biogeochemical cycles (C, N cycling) symbiotic associations with eukaryotes industrial applications o ex: fermentation, pharmaceuticals, etc.
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