Bio 1M03 Exam study Guide Latest

Bio 1M03 Exam study Guide Latest Cell theory - all organisms are made of cells and all cells come from pre-existing cells Louis Pasteur - designed an experiment to test if cells arose spontaneously or if they were the result of pre-existing cells Evolution - postulates that (a) species are related to one another by common ancestry and (b) species can change through time from generation to generation. Natural selection - process that explains how evolution occurs Fitness - the ability of an individual to produce offspring Adaptaion (noun) - characteristic that increases the fitness of an individual in a particular environment Adaptation (verb) - process of a specie getting fitness-improving traits over time Artificial selection - form of natural selection where humans control the course of evolution Phenotype - outward appearance; features that can be observed Genotype - the genetic constitution of an individual organism Speciation - the diversification of an evolutionary lineage; lines represent different phenomena Species - populations that don't reproduce amongst each other (exchange genes) Tree of Life (phylogenic tree) - diagram that depicts relationships among species Kingdom, Phylum, Class, Order, Family, Genus, Species - Linnaeus' Taxonomic Levels Bacteria, Achaea , Eukarya - the three domains Hybridization - merging of two species into one; merging lines on phylogenic tree Lateral gene transfer - in bacteria, useful information is being transferred, fused Sexual reproduction - fusion of genomes Evidence for evolution - changes through time, extinction, vestigial traits, inter-relatedness Evidence for natural selection - industrial melanism, antibiotic resistance, beak size in Galapagos finches Darwin and Wallace - proposed the theory of evolution Ring species - Five populations and the one on the left can populate with the one right beside it, that one can populate with the one right beside it, but the two species on the end of the linear relationship overlap but cannot reproduce with each other, only their adjacent populations Speciation by polyploidization - method of new species emerging by genome duplication Transitional forms - fossils with traits that are intermediate between earlier and later species Homologous traits - a similarity that exists in species that was inherited from an ancestor Genetic homology - similarity among species in DNA sequences, gene content, or other genetic attributes Developmental homology - similarity among species in embryonic traits Structural homology - example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor Vestigial traits - often homologous to structures that are functioning normally in other species Variation - mitochondrial DNA substitution of single codons Heritability - traits get passed down from generation to generation Candidate gene approach - applying info from closely related species that are more known Fitness trade-off - compromise between traits, in terms of how those traits are adapted for the environment Genetic correlation - when selection favouring alleles for one trait causes a correlated but suboptimal change in allele for another trait; changing one feature (or gene) often affects multiple features Historical constraints - Present variation biases future possibilities Formal constraints - Evolution needs to work within the laws of physics Temporal constraints - Evolution occurs by mutation and it takes time for a series of useful mutations to occur Hardy-Weinsberg equation (p^2 + 2pq + q^2 = 1 ) - estimated expected genotype frequencies from allele frequencies Hardy-Weinsberg principle - a null hypothesis that predicts what genotype frequencies should be given known allele frequencies Genetic drift - causes allele frequencies to change by chance Gene flow (migration) - introduces alleles from other population Mutation - modifies allele frequency by continually introducing new alleles, even disadvantageous ones Heterozygote advantage - pattern of natural selection in which heterozygous individuals have higher fitness than homozygous individuals Directional selection - changes the average value of a trait; an extreme value is favoured Stabilizing selection - reduces the amount of variation in a trait; keeps the average Disruptive selection - maintains or increases the amount of variation in a trait; favours the extremes over intermediate, making two distinct groups Negative frequency dependent selection - fitness is highest in rare phenotypes Positive frequency dependent selection - fitness is highest in common phenotypes Fixation - allele is present in one generation, then all generations Extinction - allele is present in one generation, but disappears completely Founder effects - subset of a population becomes isolated from the rest causing a decrease in genetic variation Bottleneck effects - decrease in the size of a population that causes loss of genetic variation Inbreeding - increases the frequency of homozygotes which reduces the number of heterozygotes and leads to a decrease in fitness, changes genotoype frequencies Inbreeding depression - decline in average fitness that takes place when homozygosity increases and heterozygosity decreases in a population, changes allele frequencies Sexual selection - occurs when individuals within a population differ in their ability to attract mates, favours individuals with heritable traits that enhance their ability to obtain mates Fundamental symmetry of sex - in most species females usually invest more into their offspring than the males and therefore the females should be choosy about their mates while the males compete with each other for mates