Chapter 12

The main evolutionary advantage of sexual over asexual reproduction is that it produces ___________. a. more offspring per individual b. more variation among offspring c. healthier offspring

Meiosis functions in ___________. a. asexual reproduction of single-celled eukaryotes b. growth and tissue repair in multicelled species c. sexual reproduction d. both a and b

Sexual reproduction in animals requires ___________. a. meiosis c. spore formation b. fertilization d. a and b

Meiosis ___________ the parental chromosome number. a. doubles c. maintains b. halves d. mixes up

Crossing over mixes up ___________. a. chromosomes c. zygotes b. alleles d. gametes

Crossing over happens during which phase of meiosis?

The stage of meiosis that makes descendant cells haploid is _____________. a. prophase I d. anaphase II b. prophase II e. metaphase I c. anaphase I f. metaphase II

Dogs have a diploid chromosome number of 78. How many chromosomes do their gametes have? a. 39 c. 156 b. 78 d. 234

____________ contributes to variation in traits among the offspring of sexual reproducers. a. Crossing over c. Fertilization b. Random attachment d. both a and b of chromosomes e. all are factors to spindle poles

Which of the following is one of the very important differences between mitosis and meiosis? a. Chromosomes align midway between spindle poles only in meiosis. b. Homologous chromosomes pair up only in meiosis c. DNA is replicated only in mitosis. d. Sister chromatids separate only in meiosis. e. Interphase occurs only in mitosis.