StudyGuide-09-S - BOT131 Spring 2008 Sec. A-B, D-G : Dr....

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BOT131 Spring 2008 Sec. A-B, D-G :: Dr. Liang :: Study Guide 09 Page 1 of 5 KEYTERMS 01. Adaptation: because of natural selection, prolonged exposure to a stable environment can cause a species to accumulate hereditary traits that enhance success in that environment; an evolutionary modification that improves an organism’s chances of survival and reproductive success 02. Evolution: cumulative genetic changes in a population of organisms from generation to generation; population whose allele frequency changes over time; changes over time in inheritable characters of population of living organisms 03. Genetic Drift: a random change in allele frequencies in a small breeding population 04. Natural Selection: the mechanism of evolution in which individuals with inherited characteristics well suited to the environment leave more offspring than individuals that are less suited to the environment do 05. Directional Selection: peak moves to left or right; see video 06. Disruptive Selection: two peaks form; see video 07. Stabilizing Selection: reduces diversity; graph becomes narrower in middle; see video 08. Artificial Selection: modification of species over time by humans through selective breeding 09. Allele Frequency: the proportion of a specific allele in the population 10. Selective Agent : any factor that could bring an evolutionary changes (i.e., allele frequency changes over time) for a population. 11. Mutation: DNA changes at random points; a change in the nucleotide sequence of DNA of an organism 12. Mutagens: agents that cause mutation; with lichen, it was air pollution 13. Recombination: the appearance of new gene combinations; recombination in eukaryotes generally results from meiotic events, either crossing over or shuffling of chromosomes; a process that creates a new combination of genes joining parts of DNA from separate organism 14. Fitness: an individuals’ ability to propagate its genes; the capability of an individual to propagate its genes. Within a population for a given species, there might be different genotypes (different genetic make-ups, e.g., different alleles). Suppose a genotype can produce more children than others under certain conditions. Therefore, this genotype has high fitness to the particular conditions. 15. Plant Hybridization: the interbreeding between two plants, either from the same species or from different species. 16. Hybrids: the offspring of individuals belonging to different species 17. Allopatric Speciation: evolution of a new species that occurs when one population becomes geographically separated from the rest of the species 18. Sympatric Speciation: evolution of a new species that occurs within the parent species’ geographic region 19. Parapatric Speciation: evolution of a new species that results from reproduction isolation between adjacent members of a population
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StudyGuide-09-S - BOT131 Spring 2008 Sec. A-B, D-G : Dr....

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