BIOL 102 Exam 1 Comprehensive Study Guide (9/08/16 Exam)
BIOL 102 Exam 1 Comprehensive Study Guide (9/08/16 Exam) BIO 102
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This 9 page Study Guide was uploaded by Zach Notetaker on Monday September 5, 2016. The Study Guide belongs to BIO 102 at University of South Carolina taught by Mihaly Czako in Fall 2016. Since its upload, it has received 99 views.
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Date Created: 09/05/16
Biology 102 Exam 1 Study Guide Darwin: 1859 Origin of Species focused on great diversity of organisms noted that current species = descendants of ancestral species Evolution (Darwin definition) = descent with modification o as opposed to Aristotle who thought species = fixed and arranged on linear model, w/ increasing complexity Linnaeus adaptations o taxonomy, binomial nomenclature CLASSIFICATION FORMAT Fossils laid groundwork for Darwin and his ideas o Cuvier, Hutton, Lyell influenced Darwin Lamarck species evolve thru use and disuse of body parts, inheritance of acquired traits SS Beagle Darwin’s ship around globe o Found Earth much older than previous 6,000 yr. old estimate o Biological diversity on Galapagos + adaptation and it’s connection to the origin of new species o 1844 Darwin write essay on natural selection 3 Broad Observations: unity of life diversity of life match b/w organisms and their environment Evolution must have 1. varied, inherited traits 2. produce more offspring than environment can support Natural Selection: o individuals w/ certain heritable traits reproduce and survive @ higher rate than others o increases match b/w organisms and their environment o change in environment = natural selection and adaptations, can give rise to new species **INDIVIDUALS DO NOT EVOLVE POPULATIONS TO** Evidence of Evolution: 1. Direct Observation: ex) natural selection in response to introduction of new plant species ex) evolution of drug resistant bacteria 2. Homology: similarity b/w organisms & species as a result of common ancestors can be anatomical and molecular evolutionary trees o hypotheses that summarize current understandings of patterns of descent structure common in ancestors (homologous structures) Convergent Evolution: evolution of similar, or analogous features in distantly related groups arise when groups adapt independent to similar environments, but in similar ways gives NO info about ancestry 3. Biogeography: study of distribution of species evidence for evolution Endemic species not found anywhere else in the world 4. The fossil record: documents pattern of evolution by showing changes b/w present day organisms and extinct or past ones found in strata each strata layer = catastrophic event Fossil record shows macroevolutionary changes over large time scales Fossil record is biased in favor of species that: Existed for long time We abundant and widespread Had hard parts Absolute ages of fossils determined by radiometric dating Radioactive “parent isotope decays to “daughter” isotope at constant rate Each isotope known as half life time required for ½ parent isotope to decay Adaptation: o characteristics of organisms (inherited) that enhance their fitness (survival) and reproduction w/in environment ex) Finches in Galapagos different adaptations based off different food sources on specific islands Artificial selection: o selection and breeding of individuals who posses desired traits ex) HUMANS! Darwin’s Observations & Interferences: o Observations: varied inherited traits w/in populations species produce more offspring than environment can support w/ many failing to survive and reproduce o Interferences: individuals w/ traits w/ high probability of surviving and reproducing w/in specific environment leave more offspring inequalities w/ individuals being able to survive and reproduce leave to accumulating of good traits in populations over generations Microevolution: o change in allele frequencies in population over generations o 3 Mechanisms: Genetic Drift: small sample = greater chance of random deviation from predicted result allele frequencies fluctuate from one generation to the next reduces genetic variation because alleles are lost o Founder Effect: few individuals become isolated from larger population allele frequencies can be different from ours in larger population Bottleneck Effect: sudden reduction in population size due to changes in environment new gene pool could no longer be same as larger populations’ if population remains small, genetic drift can affect it more humans can create bottleneck effect for other species Gene Flow: movement of alleles among populations o transferred thru individuals or gametes reduces genetic variation over time increase and decrease fitness of populations Genetic Variation: o differences in genes or other DNA segments o Phenotype product of inherited genotype and environment some differences determined by a singlegene, others by influence of 2 or more genes o measured by gene variability or nucleotide variability o average heterozygosity: average percent of loci that are heterozygous o nucleotide variability measured by comparing DNA sequences of individuals LOTS OF GENETIC VARIATION @ DNA LEVEL** o mutation of duplication o sexual reproduction – recombining existing alleles Forming new alleles: mutation = random change in DNA nucleotide sequence only mutations in gametes can be passed on to offspring point of mutation = change in one base in a gene Effects of mutation: harmful for protein production o sometimes beneficial neutral variation = no advantage of disadvantage Altering Genes: o delete, disrupt, rearrange loci harmful o duplication of small pieces increase genome size duplicated genes take on new functions by further mutation o mutation rates low in plants and animals 1 in every 100,000 o lower in prokaryotes, higher in viruses HardyWeinberg Equation: o Population: localized group of individuals that can interbreed and produce offspring o Gene pool: all alleles for all loci in a population o Fixed locus: all individuals in population must be homozygous for same allele o 2 alleles @ each locus, p & q represent frequencies of dominant and recessive alleles for populations ALL alleles in population add up to 1 (there can be more than 2 alleles!) ex) p + q = 1 o equation describes genetic makeup of population that is NOT evolving IF observed genetic makeup differs from HardyWeinberg…population is evolving Populations that meet the following expectations are in HardyWeinberg equilibrium: 1. NO mutations 2. Random mating 3. NO natural selection 4. LARG E population size 5. NO gene flow Genotypes: o p = frequency of population with homozygous (often dominant) genotype o 2pq = frequency of population with heterozygous genotype o q = frequency of population with homozygous (often recessive) genotype 2 2 o p + 2pq +q = 1 3 different types of natural selection: 1 . Directional selection: favors individuals at one end (extreme) of phenotypic range 2 . Disruptive selection: favors individuals @ both ends (extremes) of phenotypic range 3 . Stabilizing Selection: favors intermediate variants and acts against extreme phenotypes Sexual Selection: natural selection for mating success Sexual Dimorphism: marked differences b/w sexes in secondary sexual traits o Types: Intrasexual Selection: direct competition among individuals of one sex (mainly males) for mates of the opposite sex Intersexual Selection: “mate choice” individuals of one sex (mainly females) are choosy in selecting their mates Balancing Selection: natural selection maintains stable frequencies of 2 or more phenotypic forms w/in a population Including… o Heterozygote advantage: when heterozygotes have higher fitness than both homozygotes can result from stabilizing or directional selection o Frequencydependent selection: fitness of phenotype declines if it becomes too common in population whichever phenotype is less common in population History of Life On Earth: o Chemical and physical processes in early Earth may have produced simple cells through sequence of stages: 1. Abiotic synthesis of small organic molecules 2. Joining of these molecules into macromolecules 3. Packaging of molecules into protocells 4. Origin of selfreplicating molecules Protocells: o Replication and metabolism are key properties of life and may have appeared in protocells o Protocells may have formed from fluidfilled vesicles in membranelike structure o Vesicles exhibit simple reproduction and metabolism & maintain internal chemical environment different from external First genetic material probably RNA, not DNA Absolute ages of fossils determined by radiometric dating Radioactive “parent isotope decays to “daughter” isotope at constant rate o Each isotope known as half life time required for ½ parent isotope to decay Macroevolution: broad patterns of evolutionary change above species level, by same mechanisms that cause microevolution (see Microevolution definition) Biological Species Concept: species = group of population whose members can interbreed in nature and produce viable, fertile, offspring; DON’T breed successfully with members of other populations o Gene flow b/w populations of same species holds a species together genetically Limitations: Can’t be applied to fossils or asexual organisms Emphasizes absence of gene flow BUT gene flow can occur b/w distinct species when some barrier is broken naturally or artificially Reproductive Isolation: existence of biological factors (barriers) impeding two species from producing viable, fertile offspring Hybrids: offspring of crosses b/w different species o Pre or post fertilization Prezygotic barriers: block fertilization from occurring by… o Impeding different species attempting to mate o Preventing successful completion of mating o Hindering fertilization if mating successful Postzygotic barriers: prevent hybrid zygote from developing into viable, fertile adult o Reduced hybrid viability o Reduced hybrid fertility o Hybrid breakdown Morphological Species Concept: defines species by structural features o Applies sexual and asexual species but relies on subjective criteria Ecological Species Concept: views a species in terms of its ecological niche o Applies sexual and asexual species and emphasizes role of disruptive selection Phylogenetic Species Concept: defines species as smallest group of individuals on phylogenetic tree o Applies to sexual and asexual species but can be difficult to determine degree of difference required for separate species Allopatri (“Other Country”) Speciation: gene flow interrupted or reduced when population divided into geographically isolated subpopulations ex) flightless cormorant of Galapagos originated from flying species on mainland o Definition of barrier depends on ability of population to disperse ex) canyon can create barrier for small rodents, NOT birds, coyotes, or pollen o Separate populations can evolve independently thru mutation, natural selection, genetic drift o Reproductive isolation can arise as byproduct of genetic divergence Increases as distance b/w species increases o Regions with lots of geographic barriers have typically have more species than do regions w/ fewer barriers Physical separation alone isn’t biological barrier, reproductive barrier are intrinsic to organisms themselves Sympatric (“Same Country”) Speciation: speciation takes place in geographically overlapping populations o Reproductive barrier isolates subset of population w/out geographic separation from parent species o Can occur if gene flow is reduced by following factors: Polyploidy: presence of extra sets of chromosomes due to accidents during cell division Much more common on plants than animals Can produce new biological species in sympatry w/in single generation o Autopolyploid: individual with more than 2 sets of chromosome sets (derived from single species) o Allopolyploid: species with multiple sets of chromosomes derived from different species Sexual Selection: can drive sympatric speciation Habitat differentiation: appearance of new ecological niches ex) North American maggot fly can live on native hawthorn trees & more recently introduced apple trees
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