ASU BIO 182 EXAM 2

ASU BIO 182 EXAM 2 asexual reproduction directing cells to divide and develop into new tissues and organs without a partner sexual reproduction -takes more time and energy than asexual reproduction -genetically diverse offspring -requires fertilization -requires haploid gametes -mating most plants and animals produce_______ gametes called eggs and sperm Meiosis nuclear division that forms haploid cells Meiosis I diploid cells divide to create 2 haploid cells, each with one of the homologous chromosomes Meiosis II 2 haploid cells divide to form 4 haploid cells, which develop into eggs or sperm Prophase I (Meiosis) -chromosomes condense -nuclear envelope breaks down -spindle fibers start to form (microtubules) -crossing over occurs Metaphase 1 (Meiosis) Pairs of homologous chromosomes move to metaphase plate Anaphase I (Meiosis) homologous chromosomes separate and move to opposite poles of the cell Telophase and Cytokensis (Meiosis) -chromosomes gather at poles of the cell -cytoplasm divides Prophase II (Meiosis) -2 cells -a new spindle forms around the chromosomes Metaphase II (Meiosis) chromosomes line up at the metaphase plate/equator Anaphase II (Meiosis) -2 cells -centromeres divide -chromatids move to opposite poles of the cells Telophase II and Cytokinesis (Meiosis) -goes from 2 cells to 4 cells -nuclear envelope forms around each set of chromosomes -cytoplasm divides Asexual organisms -New alleles must occur independently -can't be passed around and mixed with the genetic make up/ different alleles of other organisms Sexual organisms -populations can accrue new beneficial alleles in a shorter period of time than asexual organisms -organisms in a population can share beneficial alleles -takes all the best alleles and puts them in a "basket" that selection can favor sex creates_____ -genetic variation among offspring -allows populations to adapt to environmental change faster organisms in more variable environments______ -show a higher propensity (a preference) for sexual reproduction compared to asexual -could be due to increase in genetic variation to increase rate of adaptation to the environment linked alleles/genes -genes are close together on the same chromosome -breaks the law of independent assortment -genes closer to each other on a chromosome are less likely to recombine during crossover crossing over enables_____ an organism to recombine alleles on the same chromosome with alleles on a homologous chromosome genetic drift -a process through which populations evolve randomly -by chance, some individuals have more offspring than others -smaller populations evolve rapidly Bottleneck effect -loss of genetic diversity following a sudden drop in a population -can occur in a single generation genetic drift occurs when_____ a portion of the population dispersed to a new habitat/ becomes separated by a physical barrier founder effect -loss of alleles that occur when individuals start a new, smaller population -increases chances of genetic disorder natural selection -causes phenotypes to evolve in a particular direction -requires repeatable differences in reproductive success among genotypes -always causes adaptation of a trait -most important mechanism of evolution in large populations Genetic drift -has a large effect on allele frequency in small populations/ small effect on large populations -requires random differences in reproductive isolation to evolve between geographically isolated sub-populations