CAMPBELL-BIOLOGY CHAPTER 23 EXAM Q’S AND A’S

CAMPBELL-BIOLOGY CHAPTER 23 EXAM Q’S AND A’S population - answer- The evolutionary impact of natural selection is only apparent in the changes in a _______ over time microevolution - answer- a change in allele frequencies in a population over generations false - answer- T or F: Natural selection is the only cause of microevolution genetic variation - answer- differences among individuals in the composition of their genes or other DNA segments True - answer- T or F: Only the genetically determined part of phenotypic variation can have evolutionary consequences heritable quantitative variation - answer- results from the influence of two or more genes on a single phenotypic character gene variability - answer- measuring genetic variation at the whole gene level nucleotide variability - answer- measuring genetic variation at the molecular level of DNA average heterozygosity - answer- Gene variability can be quantified as the _________, the average percentage of loci that are heterozygous geographic variation - answer- differences in the genetic composition of separate populations cline - answer- a graded change in a character along a geographic axis (same definition but in more colloquial terms): any gradual change in a particular characteristic of a population of organisms from one end of the geographical range of the population to the other sources for genetic variation - answer- -formation of new alleles -altering gene number or position -rapid reproduction -sexual reproduction mutation - answer- a change in the nucleotide sequence of an organism's DNA crossing over independent assortment fertilization - answer- 3 mechanisms that contribute to shuffling existing alleles population - answer- a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring gene pool - answer- consists of all copies of every type of allele at every locus in all members of the population p - answer- the frequency of the C^R allele in the gene pool of this population q - answer- the frequency of the C^W allele in the gene pool of this population Hardy-Weinberg Principle - answer- this principle states that the frequencies of alleles and genotypes in a population will remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work Equilibrium - answer- a gene pool is in Hardy-Weinberg _____ Hardy Weinberg proportion - answer- p^2 + 2pq + q^2 = 1 Conditions for Hardy Weinberg Equilibrium - answer- 1. No mutations 2. Random mating 3. No natural selection 4. Extremely large population size 5. No gene flow adaptive evolution - answer- evolution that results in a better match between organisms and their environment genetic drift - answer- A change in the allele frequency of a population as a result of chance events rather than natural selection for example: only certain organisms survive so they can reproduce and give offspring and their allele ratios for certain traits will be changed-- see page 477 in the book founder effect - answer- when a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool differs from the source population bottleneck effect - answer- Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population Genetic Drift Takeaways - answer- 1. Genetic drift is significant in small populations 2. Genetic drift can cause allele frequencies to change at random 3. Genetic drift can lead to a loss of genetic variation within populations 4. Genetic drift can cause harmful alleles to become fixed gene flow - answer- the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes