BIOL 112 Exam 1 Janes TAMU Questions and Answers correct

BIOL 112 Exam 1 Janes TAMU Questions and Answers correct Scientific Method a way of thinking -- allows us to build models of the universe to understand its actions and predict its behavior Aspects of Science Assumptions are needed to do science supernatural effects cannot be analyzed Limitations of Science cannot establish ideal behavior for humans in society cannot prove existence of deity Theory higher level: reliable, useful, valid, repeatedly tested model of some aspect of the universe scientist cannot prove right or wrong in judgments Paradigm large scale model, an encompassing theory which gives a major frame of reference EX: Mendelian Genetics, Cell Theory, Evolution Bad Theories not testable, poor predictive value, do not fit observations St. Augustine of Hippo (354-430) Addition: suggested universe was very old; recognized that organisms were changing Weakness: supernatural aspects (Unfalsifiable Theories) Linnaeus () Addition: grouping of like organisms; binomial naming Weakness: supernatural creation Georges Cuvier () Addition: 1st to realize fossils were record of ancient times; saw the distinction in earth's layers Weakness: thought each layer was caused by catastrophic event (Catastrophism) Lyell and Hutton (Geologists) Addition: ancient world acted like today's world (Uniformitarianism); Earth's strata was caused by gradual changes Jean Baptist Lamarck () Addition: life evolves as environment changes Weakness: no change in DNA sequence related to use or disuse of organ Lamarck Model not really true "snake w/legs" theory *the use or disuse of genes do not alter DNA* Charles Darwin () A British naturalist, renowned for his theories of evolution and natural selection. Voyage of the HMS Beagle lasted 5 years, traveled around the world, Darwin found the best evidence for natural selection at the Galapagos islands Darwin's Finches Several species of finch's evolved to have different beak shapes to occupy a specific niche on the Galapagos islands. Example of Adaptive Radiation Alfred Russel Wallace () British naturalist who developed the theory of evolution by natural selection in parallel with Charles Darwin Natural Selection "reproduction of the fittest" pass on the best traits to survive Darwin's Thinking Process "descent with modification" 1. variability in population 2. resources are limited (Malthus) 3. not all organisms will succeed and reproduce 4. better abilities to compete for limited resources Random Processes Variations arise from... mutations (new alleles) sexual reproduction/Recombination Random Variability acted upon Non-Random Processes Darwinian Evolution Random: Heritable variations arise in population due to genetic changes and exchanges Non-Random: natural selection sorts out variations by giving lower or higher success rates in competition for limited resources Darwin's Theory 2 Ideas 1. "Descent w/ Modification" 2. Natural Selection Did not know about genetics Evidence in Darwin's Theory Direct Observation Fossil Record (change over time) Homology (common ancestors) Convergence (adaptations) Biogeography (diversity) Direct Observation EX: Soapberry bugs adapt to new food source EX: antibiotic-resistance in bacteria Fossil Record many extinct species show change over time Homologies phylogenetic trees show the evolution between species genetic code is universal similarity in cell structures, proteins, DNA Evolutionary Convergence unrelated species show similar adaptations Biogeography distribution of species across the world species are specific to origin land Theory of Evolution by Natural Selection explains both diversity and unity of life accounts for much of form and function can predict outcome of environmental change Ways to Define Species 1. Can breed in nature 2. Can produce fertile offspring 3. Offspring viable (do not successfully interbreed w/other groups) Prezygotic Barriers prevent fertilization Habitat Isolation organisms never meet b/c of habitats Temporal Isolation mating at different times Behavioral Isolation different courtship cues Mechanical Isolation cannot hook up Gametic Isolation gametes cannot fuse Postzygotic Barriers act after a hybrid zygote is formed Reduced Hybrid Viability embryo fails to develop or is weak Reduced Hybrid Fertility hybrid survives but is sterile (mule) Hybrid Breakdown 2nd generation hybrids are feeble and sterile (happens in plants) Allopatric Speciation physical barrier isolates one population Sympatric Speciation speciation occurs in same geographical area mating behavior may lead to this type of speciation Polyploidy: new species is formed by duplication of entire genome Autopolyploidy Polyploid of one individual Allopolyploidy Polyploid of hybrid of two species Phenotype physical expression Population a group of interbreeding individuals in the same area, somewhat isolated from other groups Gene Pool all the alleles of all the genes in a population Genotypic Frequency % of each genotype in the population ex: % of AA or % of aa p2+2pq+q2 = 1 Allelic Frequency % of each allele in the population p + q = 1 Microevolution any change in population allelic or genotypic frequency over time smallest fundamental unit of evolution H-W Conditions 1. no mutations 2. mating is random 3. no selection 4. very large population size 5. no gene flow Natural Selection acts non-randomly on phenotypes of individuals changes allelic and genotypic frequencies of populations non-randomly always leads to adaptation of population to current environment Genetic Drift genetic frequency changes due to random events often occurs in small populations often reduces diversity; leads to "fixed" alleles Founder Effect Genetic Drift think "island" Bottleneck Effect Genetic Drift think "catastrophe" Gene Flow alleles move in/out of population tends to add diversity ex: migration of adults; dispersal of gametes, seeds, larvae Relative Fitness fitness is relative to other individuals in the population "fittest" = best reproductive success Directional Selection shifts character's means value to one direction Disruptive Selection intermediates (Aa) are less fit than extremes maintains diversity Stabilizing Selection intermediate (Aa) types more fit than extremes variation reduced Sexual Selection success based on traits related to obtaining mates ex: red on cardinals attract more females; males compete for females Taxonomy grouping species together Classification (Less=Most Inclusive) Species = Genus = Family = Order = Class = Phylum = Kingdom = Domain Phylogeny the evolutionary history of a species and its relationship to other species Plesiomorphy homologous characters shared with ancestor