Question

How does the role of meiosis in gamete production differ between organisms with a diploid-dominant life cycle and organisms with an alternation of generations life cycle?

a) Diploid-dominant organisms produce haploid gametes directly
b) Alternation of generations involves only asexual reproduction
c) Both life cycles exhibit identical meiotic processes
d) Alternation of generations includes sporophyte and gametophyte stages

Answer 1

In diploid-dominant organisms, meiosis directly produces haploid gametes. In organisms with an alternation of generations life cycle, meiosis produces haploid spores that develop into multicellular haploid organisms called gametophytes, which then produce gametes.

Step-by-step explanation:

In organisms with a diploid-dominant life cycle, such as most animals including humans, the role of meiosis in gamete production is to reduce the chromosome number by half, resulting in haploid gametes. These haploid gametes then combine during fertilization to restore the diploid condition. This means that diploid-dominant organisms produce haploid gametes directly through meiosis.

On the other hand, in organisms with an alternation of generations life cycle, such as plants and some algae, both haploid and diploid multicellular stages are present. The meiotic process in alternation of generations is responsible for producing haploid spores, which develop into multicellular haploid organisms called gametophytes. These gametophytes then produce gametes without directly involving meiosis. The gametes combine during fertilization to form a diploid zygote, which undergoes meiosis to produce spores and continue the life cycle.

The correct option is A.