Question

20. Phenotypic plasticity A. is when an organism survives but not does not reproduce. B. only happens for animals, not plants C. is the altered phenotype of organism based on variation in genotype. D. none of the above 21. Commensalism is when A. for example, there is colonization by a gastrointestinal bacterial species that provides neither a benefit nor an ailment for the host B. there is an exaptation due to hybridization C. there is a mixture of chromosomes as a result of hybridization D. the effects of an allele at one genetic locus relate to multiple phenotypes 22. Which of the following events likely results in an overall loss of allelic variation? A. a genetic bottleneck due to a founder effect B. a tornado impacting 99% of a small population C. mutations for a gene in a large and expanding population with minimal negative selective pressure D. all of the above E. A and B only 23. Which of these statements about the virulence of rabbit myxoma virus is true? A. Rabbit myxoma virus needed to become more virulent so it could coexist with its rabbit hosts B. Directional selection favored a coevolutionary escalation where resistance evolved in rabbits and more virulence evolved in the virus. C. Rabbit myxoma virus became less virulent over time because natural selection favored strains that did not immediately kill the rabbit hosts, enhancing the likelihood of spreading and infecting other rabbits. D. All of the above are true statements. 24. When allele and genotype frequencies remain constant across generations, this is evidence of A. horizontal transfer. B high mutation levels C. Hardy-Weinberg equilibrium. D. heterozygote and homozygote dominant genotypes being more fit than homozygote recessive genotypes 25. What types of evidence do evolutionary scientistics evaluate? A geological layers B radioisotopes C. genetic sequence comparisons D. homologous bone structure E, all of the above

Answer 1

20. C. Is the altered phenotype of an organism based on variations in genotype.

Phenotypic plasticity refers to the ability of an organism to alter or change its phenotype according to the environment by varying its genotype.

21. A.

Commensalism is the symbiotic relationship between two organisms in which one is benefited and other is neither benifited nor harmed.

22. E. A and B.

Genetic bottle is an evolutionary event which reduces the size of the population which causes loss in the genetic variability of population due to loss of genes in the original population. Genetic bottleneck occurs due to natural disasters like floods, cyclones, tornadoes, famines which can cause reduction in the number of individuals in the population.

23.

24. C. Hardy Weinberg law.

Hardy Weinberg law states that gene and phenotypic frequency in a large and randomly mating population remains constant as long as evolutionary forces remain absent.

25. C. Genetic sequence comparison.