12. Meiosis

Sexual and asexual reproduction are alike in that __________.

Fertilization produces __________.

Which of the following is part of the life cycle called alternation of generations?

The sexual cycle of the diploid, multicellular algal genus Fucus involves __________.

A life cycle in which the only multicellular form is haploid is most typical of __________.

In sexually reproducing species, the chromosome number remains stable over time because __________ and __________ always alternate.

The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit?

When we say that an organism is haploid, we mean that __________.

How many pairs of autosomes do humans have?

Which of the following is a function of mitosis in humans?

Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.

Nearly all life cycles have both haploid and diploid phases. Usually, the transition from haploid to diploid takes place __________.

Spores and gametes are different in that __________.

Humans have 46 chromosomes. This number of chromosomes will be found in __________.

Add labels to the figure that follows, which illustrates a portion of the human life cycle.

A species of rotifer, a small freshwater invertebrate, lost the ability to reproduce sexually millions of years ago. A remarkable feature of its life cycle is the ability to withstand dry conditions. When the rotifer's environment dries out, so does the rotifer, and it can be blown to a new area. Rotifers that land in water will rehydrate and resume an active life. A major pathogen of these rotifers is a species of fungus that cannot survive drying. Some scientists hypothesize that drying rids the rotifers of this pathogen. (a) Design an experimental study to test this hypothesis.

A species of rotifer, a small freshwater invertebrate, lost the ability to reproduce sexually millions of years ago. A remarkable feature of its life cycle is the ability to withstand dry conditions. When the rotifer's environment dries out, so does the rotifer, and it can be blown to a new area. Rotifers that land in water will rehydrate and resume an active life. A major pathogen of these rotifers is a species of fungus that cannot survive drying. Some scientists hypothesize that drying rids the rotifers of this pathogen. (b) Why might the ability to withstand drying reduce any potential advantage of sexual reproduction in this rotifer species?